Re: [RE-wrenches] ConnectDER
I have had two of these on my house (I upgraded my system, so had to get a larger model) and I really like them. Great guys at the company and great product. Major issue is that most utilities don't have a blanket allowance for meter collars like this one, so you may end up spending a fair amount of time trying to get a utility's approval without guarantee of success. For utilities who think that customer-owned PV is The Devil, it could be a tough sell trying to get them to make your job easier. This can be a lifesaver on some projects where strict 690.64 compliance can be expensive-- encountering a 60A interconnection on a 150A service makes this worth fighting for, especially on all-in-ones or older equipment that the homeowner isn't ready to replace. Dave On 2015/5/25 19:58, toddc...@finestplanet.com wrote: wow, engenius. thanks for posting this. http://connectder.com/products todd On Monday, May 25, 2015 4:48pm, John Blittersdorf john.blittersd...@gmail.com said: Bill, One clean way to do it would be to use a ConnectDER, but the max input is 11.5 kw. We have used several of these for under 10 k installations and have saved lots of install time. They are not cheap (approx $300+). Our power company sells them to installers. John Blittersdorf Central Vermont Solar Wind On Mon, May 25, 2015 at 12:39 AM, frenergy frene...@psln.com mailto:frene...@psln.com wrote: Wrenches, Customer currently has a hacked up 200 amp Sylvania meter/mains panel. He also is averaging a load of 74 KWhrs/day! which will require about 15 KW system size at this site. Obviously a system this size cannot backfeed the busses in the load center. Because the exiting panel is a mess anyway, I'm suggesting it gets changed out. What sort of new 200 amp service would facilitate a clean supply side connection. One thought is have separate Utility meter socket then a 12 X 12 J-box with a monster power distribution block in it and then a distribution panel (without the meter socket)...this being a way to insert a means to grid-tie between the meter and the 200 amp main breaker. A little spendy but nothing like going to higher amp service to be able to load side connect. A 400 amp panel is not an option as the existing 165' of 3 pvc underground conduit to the pole currently has 4/0 alum. The utility says it would have to be 4 for the new cable and the cost $10K+ for the upgrade. Other ideas?? Thanks in advance Bill Feather River Solar Electric ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org http://www.members.re-wrenches.org Sent from Finest Planet WebMail. ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Working Space
I learned in a Xantrex GT training (way back) that their 36 bottom clearance requirement was to avoid [most] lawn sprinklers, so that may be the case here too. I'd still plan for it to be high enough to avoid any basement flooding and to remain easy to access. May be worth discussing with SMA ahead of time in case the AHJ complains about it during the field inspection. Dave On 2015/5/13 15:47, AE Solar wrote: Great thanks. SMA says 36 to the bottom of the disco so will go with that. On Wednesday, May 13, 2015, August Goers aug...@luminalt.com mailto:aug...@luminalt.com wrote: Hi Adam, To the best of my knowledge there is no minimum height specified in the NEC. However, many inverter manufacturers specify a minimum height. You’ll need refer to the manual for that. Best, August *From:*RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org javascript:_e(%7B%7D,'cvml','re-wrenches-boun...@lists.re-wrenches.org');] *On Behalf Of *AE Solar *Sent:* Wednesday, May 13, 2015 12:37 PM *To:* RE-wrenches *Subject:* [RE-wrenches] Working Space Hey Wrenches, We are installing some inverters in a basement where the height we hang them at is limited by some windows. I'm trying to find a code reference that says how far off the ground the DC/AC disco on the inverter needs to be but am not finding one. Could be that they are in the 3' range. Not ideal but might be our best option. Anyone know where I could look up compliance? Thanks Adam Adam Katzman Autonomous Energies 4872 State Route 9G Germantown NY, 12526 www.autonomousenergies.com http://www.autonomousenergies.com (518) 567-1468 -- Adam Katzman Autonomous Energies 4872 State Route 9G Germantown NY, 12526 www.autonomousenergies.com http://www.autonomousenergies.com (518) 567-1468 ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Wire protection for ground mount
I think someone here long ago recommended solarscrim.com; when I recommended it to three contractors I heard: 1) awesome, I just bought some and I'll use this on every project! 2) too expensive, I'm getting some tennis court screening on my own and doing it myself. 3) too expensive, I'm getting some landscape cloth(?) and doing it myself. IMHO it looks pretty nice and you would only need it over where the wiring is (unless you or your customer wanted to pay for the full back to be covered, of course), but I can't comment on its cost relative to alternatives. Issue with hardware cloth, perforated metal, etc. is that you'd need to find a way to reliably bond it, and sometimes a homemade solution may have some sharp edges/points. You may be able to use a cable tray instead (depending on your BOS approach, could run that E-W to your inverters/combiner boxes in combination with N-S rolls of scrim). Or of course, look to plethora of excellent wire management options provided by your racking manufacturer. Ha ha ha. Dave On 2015/4/17 7:20, AE Solar wrote: Hey Wrenchers, Does anyone have suggestions for netting/protecting wires behind a ground mount (for keeping hands out of there...not animals). I have seen quite a few home-made'ish looking options on systems around here (screwing hardware cloth onto the back of frames/racking, etc) but am looking for a more professional optionideally something that is as clean looking as possible. For what its worth the panels will be (4) high in landscape. Thanks for any thoughts. Adam Adam Katzman - Owner/Operator Autonomous Energies 4872 State Route 9G Germantown NY, 12526 www.AutonomousEnergies.com http://www.autonomousenergies.com/ (518) 567-1468 -- Adam Katzman Autonomous Energies 4872 State Route 9G Germantown NY, 12526 www.autonomousenergies.com http://www.autonomousenergies.com (518) 567-1468 ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] How can I calculate ROI when the kWh rate varies through the day?
SAM is what you're looking for: https://sam.nrel.gov/ I didn't have much luck last time I tried to import TOU utility data, but you can enter your parameters manually if the auto-import doesn't work for you. Dave On 2015/4/8 16:15, Mick Abraham wrote: Hello, Mechanix~ A client requested a pure grid tie PV quote and of course I wish to help him project ROI return on investment. PV Watts only allows a single value to be keyed for the cents per kilowatt-hour, but my customer is on a TOU time of use billing program, so from 1 P.M. to 5 P.M. the value of his generated power is ~50% of the value during all other sunny hours. Is there a more sophisticated ROI calculation tool that allows $0.xx per kilowatt hour for one time interval then $0.yy in for a different time interval? This particular situation then also needs $0.zz for a third interval to get an accurate projection. The rooftop is skewed to the east so that skews the power delivery to benefit those hours before the value per kilowatt hour drops, so the ideal ROI tool would factor in that non-180 degree azimuth orientation, roof pitch etc. If I can think of any way to make this question more complicated, I'll post a follow up (!) Thanks in advance. The Wrench List is da bomb! Mick Abraham, Proprietor www.abrahamsolar.com http://www.abrahamsolar.com Voice: 970-731-4675 ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] TL Inverters Rapid Shutdown
All, please excuse the late addition to the thread, but I just noticed that SMA has a PDF up describing their Rapid Shutdown solution. I think it's just been uploaded in the last few weeks, so in case you hadn't seen it: http://www.sma-america.com/fileadmin/content/www.sma-america.com/Products/Documents/SMA_Rapid_Shutdown.pdf Dave On 2014/10/9 14:00, Randy wrote: Steve, Will there be a retro kit? Thanks Randy Randy Sadewic Cell: 505 570-0137 ra...@positiveenergysolar.com mailto:ra...@positiveenergysolar.com http://positiveenergysolar.com/admin/content/uploads/PES-logo-3.jpg *From:*Steve Jefferson [mailto:steve.jeffer...@sma-america.com] *Sent:* Thursday, October 09, 2014 11:31 AM *To:* ra...@positiveenergysolar.com; RE-wrenches *Subject:* RE: [RE-wrenches] TL Inverters Rapid Shutdown Morning Wrenches, SMA is developing a product to meet 690.12 requirements. It will be shown at SPI in Las Vegas. Also, you will still be able to have SPS function with the provided solution. Thanks SMA America, LLC Steve Jefferson Service Line Supervisor 3925 Atherton Ave Rocklin, CA 95765 - 3714 U.S.A. Tel: +1 916 625 3185 (direct) Fax: +1 916 625 0871 Mobile: +1 916 622 4253 Email: steve.jeffer...@sma-america.com mailto:steve.jeffer...@sma-america.com www.SMA-America.com http://www.sma-america.com/ cid:image001.png@01CF1CFA.FE18BEB0 http://www.youtube.com/watch?v=yQWzPuyqhzofeature=youtu.be This email and any attachments thereto may contain SMA America, LLC confidential, privileged and private material for the sole use of the intended recipient. Any review, copying, or distribution of this email (or any attachments thereto) by others is strictly prohibited. If you are not the intended recipient, please contact the sender immediately and permanently delete the original and any copies of this email and any attachments thereto. Thank you. *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *Randy *Sent:* Thursday, October 09, 2014 9:41 AM *To:* 'RE-wrenches' *Subject:* Re: [RE-wrenches] TL Inverters Rapid Shutdown Hi Wrenches, We are being forced to adopt 690.12 Rapid Shutdown requirement based on several explanations given to our industry: 1.otherwise we would be ignoring the life safety and put our fire fighters lives in peril 2.This product can be constructed from readily available, over-the-counter code compliant components. This (is) to be the intent of CMP4when compiling the NFPA70. We do not want to act like an industry that appears to be fighting against safety. And we know there are a few products that are code compliant, micro-inverters (don’t comply with 705.12 (D) (6) because there are no products), Solaredge, and Tigo (is it approved?) yet this is not how we choose products. And the SMA SPS inverter is not going to work in a 690.12 environment without complications as far as I can see. Appreciate comments that might support the right decision. Thanks, Randy Randy Sadewic Cell: 505 570-0137 ra...@positiveenergysolar.com mailto:ra...@positiveenergysolar.com http://positiveenergysolar.com/admin/content/uploads/PES-logo-3.jpg ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] 300W 72 cell micro inverters
Regarding the clipping, which the power electronics guys would rather I call power limiting... To be clear, Longer 100% production around noon (implied in that image that this is somehow beneficial) means this system could have produced more energy but didn't because the inverter was too small. Assuming similar efficiencies, a 300W micro-inverter clearly would have produced more energy on that day than the 250W inverter. I imagine that what you mean was that if you're locked into a certain ac limit here (either you can only use a 250W micro, or maybe your service conductors limit your ac rating) then yes, a higher dc/ac ratio may have more power limiting but will produce more energy at the expense of your kWh / kWdc yield (a consideration for some projects). Given that the ABB inverters have their highest efficiencies at the higher end of their power outputs, which is not where PV modules typically operate (unless you stick a 400W module on it), I'm curious whether a typical 280W module would actually produce more energy over a year with an Enphase 240W vs the ABB 300W in most locations. Over the full Enphase power range it's more efficient than the ABB: At ~100W dc input, Enphase is at about 96.4% efficient and the ABB 300W is at 95.8%. At ~250W input: Enphase 96.4%, ABB 96.1%. And yes, at 315W input: Enphase 76.2% steady-state, ABB 96.4%. It could go without saying (but I have momentum) that you should not spend $2000 on a larger inverter(s) that will help your array produce $200 more energy over its 25-year life. It's up to you to figure that out given your site conditions and as noted in the last thread that addressed this topic, weather data probably underestimates the benefit due to its averaging out most short-term edge-of-cloud effects. Anyway, maybe C250s would meet the OP's needs and they're actually the slightest bit more efficient than the standard 240W unit. That is, until you add the transformer since the output is 220-248V L-N. That presumably makes the ABB the efficiency winner, but hopefully the above is still useful. Sorry, no personal experience with any of the ABB/APS/C250 units. I probably should have opened with that to save you some time. DKC On 2015/2/10 13:05, jarmo.venalai...@schneider-electric.com wrote: Hi: One thing to keep in mind with clipping, (module over sizing), is that if a system has 10%-15% off clipping, that will not affect total annual energy harvest and depending on dust and temperature conditions will likely even improve it. Heres' a graph which shows the energy harvest graphically for a 250W module with a 250W inverter and a and 300W module with a 250W inverter. Please note the graph does not include any dust effects. To compensate for dust, the modules should always be of the order of 4% more powerful than the inverter, unless you plan on washing modules every month. Related to this, large commercial systems we have been supplying inverters to are 30-70% oversized as the sinking cost of modules makes the return on investment come out as maximized in that range of oversizing, JARMO _ * Jarmo Venalainen* | *Schneider Electric **| Xantrex Brand* | *CANADA* | *Sales Application Engineer* * Phone:* +604-422-2528 | *Tech Support:* 800-670-0707 | *Mobile:* +604-505-0291 * Email:* _jarmo.venalainen@schneider-electric.com_ mailto:jarmo.venalai...@schneider-electric.com | *Site:*_www.Xantrex.com_ http://www.xantrex.com/ | *Address:* 3700 Gilmore Way, Burnaby, BC V5G4M1 *** Please consider the environment before printing this e-mail From: Drake drake.chamber...@redwoodalliance.org To: RE-wrenches re-wrenches@lists.re-wrenches.org, Date: 02/10/2015 06:51 AM Subject:Re: [RE-wrenches] 300W 72 cell micro inverters Sent by:RE-wrenches re-wrenches-boun...@lists.re-wrenches.org That would be at the 120% rating, so by rule of thumb, OK. I have a ground mount that has a ration of 1.15% with M-190s (figuring 199 W / inverter). It has quite a bit of clipping in the spring. It has optimized tilt for the location. A ballasted roof mount with a 10 or 15 degree tilt likely wouldn't have that issue. This system went in the spring of 2010, and has only had one M-190 failure out of 24, amazingly enough. At 10:22 AM 2/9/2015, you wrote: What do you typically get out of a 300 watt panel for production when you are grid tied? I know in theory (STC) it is a 300 watt module but we rarely if ever (except in very cold weather)see near that for an output. I use (as a general, 77 degrees F) design parameter, 77% for overall power production output output. I'm sure you would get a little clipping, but I guess a significant amount would depend on a number of variables on the site, time of the year,
Re: [RE-wrenches] How Is Rapid Shut-Down Not A Farse...
Mark- 690.56(C) provides the placard you're looking for and 690.56(B) tells the first responder where that 690.12 switch is, right? For 2017 there are a couple of proposals out there. One is trying to better educate that first responder (quickly!) as to what hazards exist. Another is clarifying some of the language for 690.12 such that we continue to have [better] array-level shutdown. Another is changing 690.12 to [basically] module-level shutdown, which has been signed onto by the IAFF, insurance companies, and... some module-level electronics vendors. We've installed many, many rooftop systems but we're only about 0.1% done with them. Regardless of how 690.12 changes, I think that in the next few years we'll all be revisiting every system we've ever worked on to make sure there's enough labeling to inform firefighters about the hazards. I'm curious how we're going to do that so that a 2027 firefighter can quickly distinguish between 2014's Rapid Shutdown, 2017's Even Rapider Shutdown, 2020's BlockOutTheSun Shutdown, 2014's Rapid Shutdown That Actually Still Works, 2011's System That Will Only Shock You If You Cut Through a Module, and 2005's Never-Code-Compliant system that incorrectly has a Rapid Shutdown label on it because the homeowner noticed that their neighbor had one. Somehow we need to make sure firefighters know exactly what they're up against. Non-farcically, DKC On 2015/2/5 20:08, Mark Frye wrote: ...without a mandatory Stop switch co-located with the service meter or main breaker? How many roof top systems have been installed to date? Many, many, many, many. OK ,now I am a first responder showing up at a home that is on fire. How do I know whether or not the DC has been installed such that it provided the protections afforded by 690.12? I don't. Because it is not require for systems conforming to 690.12 to look any different to me than those that do not. So does the stop switch become the new fire fighters club logo? If you have the switch the FD will save your home, if you don't they will let it burn down, even if you have a 690.12 compliant system that does not include an initiator switch? Mark Frye ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Interconnection with Generator
The inverter to generator ratio is entirely the designer's call and comes into play for large generators (for residential systems as mentioned in earlier replies, it's a bad idea). Interconnecting in spot networks in dense urban areas has a similar issue in that the distribution system can't handle backfeed. In downtown Boston a few years ago I believe that the max PV that could be interconnected was something like 1/10 or 1/15 of the demonstrated MINIMUM demand for that building over the previous year-- just to make absolute sure that there wasn't a chance of backfeed. Other solutions include things like reverse power relays such that if the PV system does start backfeeding the system, the relay would trip the inverter offline. Of course any time you're interconnecting on the load side, you of course take responsibility for anything bad that happens with the generator. This should lead to an extremely conservative ratio being used and regular monitoring to verify that the PV never comes close to backfeeding something it shouldn't. Also, any issues with power quality (real or perceived) can complicate your project substantially, thinking of William's recent issues with the UPS and Sunny Islands. I wonder if this could complicate a generator warranty, too, unless you were somehow able to get the manufacturer's blessing ahead of time. Another comment I remember from an earlier Wrench conversation was that inverter contributions on the load side of a generator won't proportionally drop fuel consumption-- that is, if your generator's load is 500kW and your PV is putting out 250kW, you're not going to have a 50% reduction in fuel use. So it takes some equipment-specific analysis to figure out what exactly your customer's savings would be. DKC On 2014/10/28 12:35, Phil Forest wrote: Interconnecting the inverter output to the utility side of the transfer switch is not necessarily an absolute rule. A knowledgeable solar EE told me a few years back, that interconnection can be made on the load side if the inverter kW output is small compared to the generator kW, that large kW generators can produce clean AC power allowing the inverter to operate and to operate without risk of burning out the generator. I don't remember what the inverter to generator ratio needs to be, or if other criteria needs to be met. Never tried it, we always connect to the utility side. Phil Forest South Mountain Company On Oct 28, 2014, at 10:48 AM, Corey Shalanski cshalan...@joule-energy.com wrote: Wrenches, We frequently encounter residences with backup generators. The question that arises: how should the PV system be interconnected? I have searched the archives and found some good information about this subject, but nothing definitive. I have fallen into the habit of broadly proclaiming that the PV system *must* be interconnected on the utility side of the transfer switch - in order to prevent backfeeding into the generator and thereby eliminate unintentional equipment damage. Is this concern justified? If so, should this be an absolute rule or would it depend on the generator make/model? Thanks for any insights. -- Corey Shalanski Joule Energy New Orleans, LA ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] AC combiners
Bill, typically inverters have a max OCPD that can be installed on their output, and these sizes are generally not large enough to accommodate two same-model inverters. And manuals often note that you need to have a dedicated OCPD anyway. At least if I were ever to double-up two inverters on a single breaker, I'd want to make sure I had clearance from the manufacturer to do so. Or... just buy the $75 box to combine the two. DKC On 2014/10/24 11:05, frenergy wrote: Wrenches, ...its the little things. Recently someone here brought up the issue of combining AC outputs prior to backfeeding the solar CB in the mains panel. In the past I've run AC outs from inverters into a small AC dist panel, backfeeding CBs and then ran my combined AC out from a larger CB or the busses themselves to the backfed CB in the mains panel. Is this overkill? It does seem as though, at least for just 2 inverters, this could be done with just split bolts in a gutter or dedicated J-boxor a power distribution block?? Or...?? (no wire nuts, thank you) Your ideas appreciated. Bill Feather River Solar Electric ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Mounting height
I believe that I was told in a 2005-ish Xantrex GT training that their minimum clearance (~30) requirement came from the need to be above lawn sprinklers. I can't remember offhand seeing this reason given in any recent manual, so any bottom clearances required in the manual may apply to you even if you're inside. On 2014/10/23 0:59, frenergy wrote: Bob-O, Peter, Garrison, I appreciate the responses, will proceed accordingly. I have seen some references to minimum distance to floor in some manuals. Thank you, Bill Feather River Solar Electric - Original Message - *From:* Garrison Riegel mailto:garri...@solarserviceinc.com *To:* 'RE-wrenches' mailto:re-wrenches@lists.re-wrenches.org *Sent:* Wednesday, October 22, 2014 11:11 AM *Subject:* Re: [RE-wrenches] Mounting height Bill, See 2011 NEC 690.14(D) or 2014 NEC 690.15(A) Utility-Interactive Inverters Mounted in Not Readily Accessible Locations. Basically there is no maximum height restriction for inverters but there are a number of requirements for AC and DC disconnecting means. See NEC 404.8 for maximum disconnect height of 6’ 7”…although exception No. 2 may allow the disconnect to be accessible by portable means. I don’t know of any minimum height requirements in the code, although most (all?) string and microinverter manufacturers specify a required clearance below the inverter. I suppose that would be the minimum. Garrison Garrison Riegel Project Manager | /Solar Service Inc/ http://www.solarserviceinc.com/ [p] 847-677-0950 | garri...@solarserviceinc.com mailto:garri...@solarserviceinc.com NABCEP Certified PV Installation Professional™ *From:*RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *frenergy *Sent:* Tuesday, October 21, 2014 11:02 PM *To:* RE-wrenches *Subject:* [RE-wrenches] Mounting height Wrenches, I can't seem to find a reference to the heights allowable for inverter installs, either minimum or maximum (need both). For that matter, AC combiners, DC discos, any switchgear related to the inverter(s). Any help appreciated. Bill Feather River Solar Electric solar powered since 1982 ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Wire management devices
I think that someone on this list recommended Solar Scrim a while back to make the conductors no longer readily accessible after they're supported; two options, depending on how picky the QA inspector is. http://www.solarscrim.com/ DKC On 2014/10/12 10:55, Christopher Warfel wrote: I looked through the archives and saw that this was a topic a few years back. I am looking for ground mounted wire management equipment that actually does something other than just support conductors. I know several quality assurance program inspectors want to see ground mounted conductors inaccessible, and how inaccessible is determined is a pretty big hole. I am wondering if anyone has used a system that seems to be accepted. Thank you, Chris ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] TL Inverters Rapid Shutdown
There is some pressure on NM specifically to postpone adoption of 690.12 until more products are available, so that may help you out. To my knowledge, micro-inverters don't need to comply with 705.12(D)(6) since there are no suitable products available [90.4]. Equipment does need to be listed, and it does need to provide rapid shutdown functionality, but it does not need to be listed for rapid shutdown to be code-compliant since that isn't a thing. String inverters generally speaking would have to have some method of control within 10' of a rooftop array, like contactor combiners. I'm interested in seeing what SMA's solution is, since contactor combiners (as discussed earlier in this thread) aren't well suited for these multi-MPPT inverters. I guess you can always add a second contactor but I don't know what listed equipment is available right now (so... 90.4?). DKC On 2014/10/9 12:41, Randy wrote: Hi Wrenches, We are being forced to adopt 690.12 Rapid Shutdown requirement based on several explanations given to our industry: 1.otherwise we would be ignoring the life safety and put our fire fighters lives in peril 2.This product can be constructed from readily available, over-the-counter code compliant components. This (is) to be the intent of CMP4when compiling the NFPA70. We do not want to act like an industry that appears to be fighting against safety. And we know there are a few products that are code compliant, micro-inverters (don’t comply with 705.12 (D) (6) because there are no products), Solaredge, and Tigo (is it approved?) yet this is not how we choose products. And the SMA SPS inverter is not going to work in a 690.12 environment without complications as far as I can see. Appreciate comments that might support the right decision. Thanks, Randy Randy Sadewic Cell: 505 570-0137 ra...@positiveenergysolar.com mailto:ra...@positiveenergysolar.com http://positiveenergysolar.com/admin/content/uploads/PES-logo-3.jpg *From:*RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *Steve Jefferson *Sent:* Tuesday, October 07, 2014 8:33 AM *To:* RE-wrenches *Subject:* Re: [RE-wrenches] TL Inverters The first gen of TL’s did have a somewhat tight window for the DC window. However, the new SBTL-US-22 (3kW – 7700kW, with secure power supply) Start Voltage is 125, MPPT is 175-480 (max of 600Vdc) Also, for larger needs, the STP (12kW – 24kW) start voltage is 150, MPPT is 300-800V (max of 1000Vdc). SMA America, LLC Steve Jefferson Service Line Supervisor 3925 Atherton Ave Rocklin, CA 95765 - 3714 U.S.A. Tel: +1 916 625 3185 (direct) Fax: +1 916 625 0871 Mobile: +1 916 622 4253 Email: steve.jeffer...@sma-america.com mailto:steve.jeffer...@sma-america.com www.SMA-America.com http://www.sma-america.com/ cid:image001.png@01CF1CFA.FE18BEB0 http://www.youtube.com/watch?v=yQWzPuyqhzofeature=youtu.be This email and any attachments thereto may contain SMA America, LLC confidential, privileged and private material for the sole use of the intended recipient. Any review, copying, or distribution of this email (or any attachments thereto) by others is strictly prohibited. If you are not the intended recipient, please contact the sender immediately and permanently delete the original and any copies of this email and any attachments thereto. Thank you. *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *Mark Byington *Sent:* Tuesday, October 07, 2014 6:59 AM *To:* RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org *Subject:* Re: [RE-wrenches] TL Inverters Just a word of caution to those not having experience with SMA TL inverters - the larger units (7-11 kW) have an extremely narrow input DC voltage window. Depending on your module voltage and string design, all you need is a module or two to be shaded to fall out of the MPPT input voltage range. The smaller units (3-5 kW) with the Secure Power Supply don't have this problem. We no longer use these larger SMA TL inverters unless we can do maximum string length (e.g. strings of 8 for SunPower 96-cell) and there is zero shade at the site. I believe SMA is in the process of adding larger units to the line that has the Secure Power Supply. They added the 6 kW unit earlier this year, and just announced the 7 kW unit with Secure Power Supply. Mark Byington Cobalt Power Systems, Inc. ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org ___ List
Re: [RE-wrenches] TL Inverters Rapid Shutdown
And... after seeing boB's email I realize that my last sentence is incorrect given the existence of the MNPVHV8-DLTL-3R for exactly this purpose. DKC On 2014/10/9 15:29, Dave Click wrote: There is some pressure on NM specifically to postpone adoption of 690.12 until more products are available, so that may help you out. To my knowledge, micro-inverters don't need to comply with 705.12(D)(6) since there are no suitable products available [90.4]. Equipment does need to be listed, and it does need to provide rapid shutdown functionality, but it does not need to be listed for rapid shutdown to be code-compliant since that isn't a thing. String inverters generally speaking would have to have some method of control within 10' of a rooftop array, like contactor combiners. I'm interested in seeing what SMA's solution is, since contactor combiners (as discussed earlier in this thread) aren't well suited for these multi-MPPT inverters. I guess you can always add a second contactor but I don't know what listed equipment is available right now (so... 90.4?). DKC On 2014/10/9 12:41, Randy wrote: Hi Wrenches, We are being forced to adopt 690.12 Rapid Shutdown requirement based on several explanations given to our industry: 1.otherwise we would be ignoring the life safety and put our fire fighters lives in peril 2.This product can be constructed from readily available, over-the-counter code compliant components. This (is) to be the intent of CMP4when compiling the NFPA70. We do not want to act like an industry that appears to be fighting against safety. And we know there are a few products that are code compliant, micro-inverters (don’t comply with 705.12 (D) (6) because there are no products), Solaredge, and Tigo (is it approved?) yet this is not how we choose products. And the SMA SPS inverter is not going to work in a 690.12 environment without complications as far as I can see. Appreciate comments that might support the right decision. Thanks, Randy Randy Sadewic Cell: 505 570-0137 ra...@positiveenergysolar.com mailto:ra...@positiveenergysolar.com http://positiveenergysolar.com/admin/content/uploads/PES-logo-3.jpg *From:*RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *Steve Jefferson *Sent:* Tuesday, October 07, 2014 8:33 AM *To:* RE-wrenches *Subject:* Re: [RE-wrenches] TL Inverters The first gen of TL’s did have a somewhat tight window for the DC window. However, the new SBTL-US-22 (3kW – 7700kW, with secure power supply) Start Voltage is 125, MPPT is 175-480 (max of 600Vdc) Also, for larger needs, the STP (12kW – 24kW) start voltage is 150, MPPT is 300-800V (max of 1000Vdc). SMA America, LLC Steve Jefferson Service Line Supervisor 3925 Atherton Ave Rocklin, CA 95765 - 3714 U.S.A. Tel: +1 916 625 3185 (direct) Fax: +1 916 625 0871 Mobile: +1 916 622 4253 Email: steve.jeffer...@sma-america.com mailto:steve.jeffer...@sma-america.com www.SMA-America.com http://www.sma-america.com/ cid:image001.png@01CF1CFA.FE18BEB0 http://www.youtube.com/watch?v=yQWzPuyqhzofeature=youtu.be This email and any attachments thereto may contain SMA America, LLC confidential, privileged and private material for the sole use of the intended recipient. Any review, copying, or distribution of this email (or any attachments thereto) by others is strictly prohibited. If you are not the intended recipient, please contact the sender immediately and permanently delete the original and any copies of this email and any attachments thereto. Thank you. *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *Mark Byington *Sent:* Tuesday, October 07, 2014 6:59 AM *To:* RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org *Subject:* Re: [RE-wrenches] TL Inverters Just a word of caution to those not having experience with SMA TL inverters - the larger units (7-11 kW) have an extremely narrow input DC voltage window. Depending on your module voltage and string design, all you need is a module or two to be shaded to fall out of the MPPT input voltage range. The smaller units (3-5 kW) with the Secure Power Supply don't have this problem. We no longer use these larger SMA TL inverters unless we can do maximum string length (e.g. strings of 8 for SunPower 96-cell) and there is zero shade at the site. I believe SMA is in the process of adding larger units to the line that has the Secure Power Supply. They added the 6 kW unit earlier this year, and just announced the 7 kW unit with Secure Power Supply. Mark Byington Cobalt Power Systems, Inc. ___ List sponsored by Redwood Alliance List Address:RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive:http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org
Re: [RE-wrenches] TL inverter with long DC Feeder
William, Just to pile on here, if you're running 4 pairs of low-voltage dc for 400' you may be better off just sticking the inverters right there at the array and making the long run as 240Vac. #2s on each inverter output (22A?) would work, keeping voltage drop to 1.3%. If you choose to combine inverter outputs right there at the array (you'd need ac disconnects there anyway) you'd have to run #3/0 for a 1.3% drop. Not sure whether that's more feasible for you. DKC On 2014/10/7 16:06, Isaac Opalinsky wrote: William, What is your string configuration? The SMA TL inverters have a very low operating voltage window, going down to 125 Vdc, but you still have the issue of the disconnect. Have you looked at ABB’s (PowerOne) TL inverters: http://www.abb.us/product/us/9AAC179447.aspx?country=US? They can be programmed to operate down to 90 Vdc, and they give you the ability to combine upstream and have the 2 MPPT’s operate as one, allowing you to combine outside of the inverter and bring a single set of PV output conductors to the inverter’s DC disconnect: *Isaac Opalinsky *| Technical Trainer | *SunPower Corporation* Desk 443-569-3476 | Cell 443-277-6286 *From:*RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *William Miller *Sent:* Tuesday, October 07, 2014 12:01 AM *To:* RE-wrenches *Subject:* Re: [RE-wrenches] TL inverter with long DC Feeder Friends: If only an SMA would work here. But DC volts too low. We are using Solectria PVI5200TLS. We do not use PV wire. We transition to THWN-2 in conduit immediately. William Miller Solar On Oct 6, 2014, at 8:30 PM, Chris Mason cometenergysyst...@gmail.com mailto:cometenergysyst...@gmail.com wrote: I presumed SMA TL series. On Mon, Oct 6, 2014 at 10:02 PM, Jerry Shafer jerrysgarag...@gmail.com mailto:jerrysgarag...@gmail.com wrote: As i read the thread you say TL which TL SMA, AE ect. They have defferent dc input designs On Oct 6, 2014 12:21 PM, jay peltz j...@asis.com mailto:j...@asis.com wrote: I do believe the outback and midnite combiners have a lock hole to prevent exactly your concern. unauthorized access. jay peltz power On Oct 6, 2014, at 11:40 AM, William Miller wrote: Wrenches: We are getting up to speed on using transformer-less inverters. I have advocated long for the additional safety offered by these inverters but I am realizing the trade-offs with the new technology: The implementation gets more complicated with the requirement for PV wire, OCPD and disconnecting means for plus and minus and plus providing Arc Flash rated equipment. I am currently designing a system that will locate the PV about 400 feet from the residence. The system will utilize 2 Solectria 5200 watt inverters at the residence. I would like to provide disconnecting means for the 4 strings at the array, in case of any needed service or excavating. Preferably I’d like the disconnecting means to be deployable by a lay person (i.e. the gardener). Finding an 8 pole, arc flash, 600 VDC rated disconnect is not easy. I could install an Outback 8 circuit combiner with 8 touch-safe fuse holders. The new combiners have had dead-fronts for a while now. The gardener needs only to have a Philips screw driver to open this cover. Any better ideas out there? Thanks, William image002.jpg Lic 773985 millersolar.com http://www.millersolar.com/ 805-438-5600 tel:805-438-5600 ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org http://www.members.re-wrenches.org ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org http://www.members.re-wrenches.org ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org
Re: [RE-wrenches] Modules over vents
Flipping through the '04 plumbing code I see a few slopes called out (1/4 per 1' for fixture vents, 1 per 1' for circuit vents, 1/2 per 1' for combination drain/vent...). Fixture vents have a maximum distance of a few feet from fixture trap to vent, but I don't think this prevents you from then running that vent horizontally. 916.2 states that for vents other than stack vents or vent stacks if your vent is 40' you need to upsize the whole vent pipe (tough to do for an existing building, of course). Stack vents have a maximum developed length of 100' for a 1.5 vent which should be enough space to get away from under the PV. I don't see any slope requirements specifically for stack vents but my non-plumber's eye may be missing something. The stack vent sizing Table 916.1 appears (in part) here too and it looks like the tables match up to a 2.5: http://www.engineeringtoolbox.com/drainage-vents-d_1110.html DKC On 2014/9/24 10:19, Jason Szumlanski wrote: I am unable to find anything in the Florida code that precludes covering a plumbing vent. The code does require the vent to be 6 above the roof surface I believe. I was unable to determine if these vents need to be vertical with no bends in the attic. Obviously you wouldn't want to create a trap in the attic, but a couple of 45's to relocate a plumbing vent to accommodate more PV seems like a desirable thing to do sometimes. Does anyone know if these can be relocated, i.e. to an adjacent roof surface? On my own home I had a vent to deal with. I broke out my saws-all, split the lead like a banana and peeled it back, cut the pipe at an angle, and folded the lead back into the pipe after applying sealant between the lead and pipe. There is a 1 gap between the rim of the pipe and the back of the module. My theory on this working safely is that, a) there will be far less rainwater falling in and around this pipe with a module over it, and b) it is about 24 from the roof ridge and there is a module over it so there will be very little water sheeting down from above the vent. Code notwithstanding, I felt this was a solid method on my own home, and I have inspected it after 6 months of Florida downpours and found no issues. Jason Szumlanski Fafco Solar On Wed, Sep 24, 2014 at 6:38 AM, Bill Loesch solar1onl...@charter.net mailto:solar1onl...@charter.net wrote: Bruce, August, et al, This is but one more example of confusing terminology. A plumbing vent is not an exhaust vent! A plumbing vent (what August calls a cold vent) is provided to allow the sanitary drain traps (and perhaps more) to operate properly. Without the properly functioning traps you would have sewer gas smell and sewer gas from the plumbing fixtures. This was commonplace when indoor plumbing was introduced to early adopters. An exhaust vent is another animal entirely. An exhaust vent carries the combustion products to a suitable exterior location for dilution with ambient air. With the advent of power vented combustion appliances, a direct vent (one that takes in combustion air from the outside and naturally exhausts combustion products to the outside) is IMHO the only responsible way to install any power vented appliance in a freezing climate. (Power vented appliances come in both condensing and non-condensing flavors-they can penetrate the side wall or the roof). Originally, two separate pipes (with two independent properly separated penetrations) was used. That technique is still often used today. More recently concentric vents have been introduced both for condensing and non-condensing applications. A concentric vent can simplify some installations by putting the exhaust pipe inside a larger air intake pipe allowing for one, albeit larger, penetration. As you might imagine if the exhaust flow is hindered/diverted/redirected by an inappropriately located solar module combustion gasses will be re-ingested into the intake air. Not good for equipment performance. My understanding is the power vented _appliance manufacturer_ dictates what kind of separation/clearances are needed with their product. My guess is you find they want at least a foot of separation between the top of the inverted cone and the module. Probably not what you had in mind for an aesthetically pleasing installation. I hope this helps, Bill Loesch Solar 1 - Saint Louis Solar 314 631 1094 tel:314%20631%201094 On 23-Sep-14 6:54 PM, August Goers wrote: Bruce and All, Sorry, I hit send before I had a chance to complete my thoughts. What I meant to say was that I've found AHJs often allow us to cover cold plumbing vents but I've never tried or had any luck with covering hot vents including condensing boiler PVC vents. Once again, if in doubt you could see what the plan checker or inspector thinks. Best, August
Re: [RE-wrenches] Rapid shutdown questions
While I share Robin's optimism, I should also note the NEC 2017 690.12 committee referred to is not the code making panel. While it does have (at least) one firefighter representative among a majority of PV industry personnel, there's no guarantee that the Code Making Panel approves this committee's proposal. There could very well be a competing proposal from firefighters that requires cell-level shutdown every time a red truck drives within 1/4 mile of an array, because SAFETY! DKC On 2014/8/28, 15:16, b...@midnitesolar.com wrote: [Robin chiming in, below] Dan, The 2014 690.12 is worded poorly. That is why there is so much confusion. MidNite Solar is sitting on the NEC2017 690.12 committee. There are a lot of smart people in this group. The 2017 version says ALL PV SYSTEMS, not just on or in buildings. The 10 foot space gets reduced to 1 foot like it always should have been. There will be a lot of other clarifications too. The systems that use shunt trip breakers [with Remote Trip coil] and contactors are for string inverters. Shunt trip breakers will be used for battery based systems and grid tie inverters with an AC outlet like the SMA TL series. Micro inverters do not require anything like what our system is. They can use the existing backfed breaker in the main distribution box as long as it is labeled accordingly. Solar Edge has a system that meets the Rapid Shutdown requirement also. The UL standard for Rapid Shutdown has been written. It is going to go out to a task force for review, comment and changes soon. MidNite Solar will be on that task force. The MidNite Birdhouse is going through UL now and is being evaluated to this new standard. All of our disconnecting combiners and SOBs are already ETL listed. UL is modifying the new Rapid Shutdown Draft standard as they come upon things in the Birdhouse that the standard didn't consider. One of the biggies that has not been sorted out is a requirement for feedback. Contactors, power supplies and a switch will meet the requirement for 2014. The issue with this type of system is that when you push the button to turn off the contactors, there is no way to tell that they actually opened up. Without feedback that verifies that the contactors are actually open, you are taking a chance with people's lives. 600VDC contactors can weld themselves closed. If first responders don't trust the Rapid Shutdown system, they are going to let the house burn. We do have feedback on the birdhouse system. Contactors do not have feedback. It is not simple to add this feature to a contactor based system. Installing a switch 15 feet up on the side of a building or on the roof is not the intent of 690.12. This will not be allowed in 2017. The exact placement of the initiating device (Birdhouse) is not cast in concrete due to the differences in where main panel boards are located, but it will not allow things like mentioned here 15 feet up in the air or in the attic or on the roof. Battery based systems are the most complicated to meet 690.12. The NEC committee is deferring a lot of this to MidNite as we are already doing it and have gone over all the different ways things can go wrong. We started designing our system right after the Bakersfield fire 5 years ago. The Bakersfield fire is what got the NEC to require disconnecting combiners. We couldn't imagine why a fire fighter would want to get up on the roof of a burning building to look for a combiner? This is why we started the birdhouse project way before anyone ever thought of the words Rapid Shutdown. Turns out this was a good thing since battery backed up systems make the issue ten times more complicated. We spent years working out issues and there were lots of them that required a start from scratch approach numerous times. AC coupling to a battery based inverter does not automatically meet 690.12 as someone mentioned in this thread. That battery based inverter must also be shut off. The micro inverters would of course shut off when the utility is shut down, but the battery based inverters job is to keep things powered up when the grid is down. So the battery based inverter has to be shut down also. It would also make sense to shut off an auto start generator with the Rapid Shutdown button. Some generators are designed to start up upon loss of grid. Once the first responders have the meter pulled, that could start up a generator and cause risk of shock. If the generator is designed to start on low battery, it could start a day later when the fire has been put out, but that also poses risk of electrical shock when unexpectedly the part of the house that is left all of a sudden comes live with juice. The cost for a Rapid Shutdown system will vary a lot depending on what you want to shut down. You do not need to run conduit to all the boxes and switches. There is 600V Cat5e 90C USE-2 cable available that will suffice. I don't see a
Re: [RE-wrenches] Batteries in a dwelling - Venting Concorde AGMs
I don't have that reference, but I believe that IFC 608 only comes into play with large banks with 50+ gallons of electrolyte. On 2014/7/29, 14:10, Glenn Burt wrote: Also look to see if the fire code in your state has additional restrictions. In New York Stat, the 2010 Fire Code contains a section (608) with more regulations to be heeded when installing 'stationary storage batteries'. -Glenn *From:*RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *Drake *Sent:* Tuesday, July 29, 2014 12:01 PM *To:* RE-wrenches *Subject:* Re: [RE-wrenches] Batteries in a dwelling - Venting Concorde AGMs This is a reply to a post by Alan from June 21st. I'm replying because I've had to deal with this issue also. It seems to me that the 2014 NEC Handbook is _fairly_ clear that we are not required to vent any batteries to the outside. *480.9 Battery Locations *Battery locations shall conform to 480.9(A), (B), and (C). *(A) Ventilation. *Provisions appropriate to the battery technology shall be made for sufficient diffusion and ventilation of gases from the battery, if present, to prevent the accumulation of an explosive mixture. Ventilation is necessary to prevent classification of a battery location as a hazardous (classified) location, in accordance with Article 500. Mechanical ventilation is not mandated. Hydrogen disperses rapidly and requires little air movement to prevent accumulation. Unrestricted natural air movement in the vicinity of the battery, together with normal air changes for occupied spaces or heat removal, normally is sufficient. If the space is confined, mechanical ventilation may be required in the vicinity of the battery. Hydrogen is lighter than air and tends to concentrate at ceiling level, so some form of ventilation should be provided at the upper portion of the structure. Ventilation can be a fan, roof ridge vent, or louvered area. Although valve-regulated batteries are often referred to as sealed, they actually emit very small quantities of hydrogen gas under normal operation and are capable of liberating large quantities of explosive gases if overcharged. These batteries therefore require the same amount of ventilation as their vented counterparts. I think that the confusion come is with the statement These batteries therefore require the same amount of ventilation as their vented counterparts. As we see from the statement Unrestricted natural air movement in the vicinity of the battery, together with normal air changes for occupied spaces or heat removal, normally is sufficient, the concern is with explosive gasses being restricted to a small area, where explosive concentrations of hydrogen can build up. The article also has the statement Provisions appropriate to the _battery technology_ which should be taken into account. In practice, liquid electrolyte batteries stink and emit toxic fumes, so we do vent these outside. It does sound like different voices have worked their way into this code section, which can open the way to various interpretations. But, if you look at the photos in the NEC Handbook of batteries, they are on unenclosed racks inside of a building. Drake At 12:06 AM 6/22/2014, you wrote: Bob, We had a case in February in which an AHJ insisted that we vent a Midnite cabinet with a dozen 2V 9150T batteries. We fought it all the way to the state Technical Advisory Committee, the top arbiter of Code issues. We fought to a draw: we finally agreed to put in the vent to get our final passed, and the committee permanently tabled the issue so there is no precedent set. To continue to fight this would have required bringing in professional engineers, as some of the committee members were reluctant to make their own decisions about the issue and wanted to pass the buck. As I recall, the Zephyr Power Vent was ultimately never hooked up to the Classic controller's auxiliary, as the necessary work was handled by the GC (rather than by us) at a quite remote location. The challenge to the AHJ was a pain in the butt, although we were paid by the clients for the effort, as they agreed with the absurdity of the inspector's demand. I have attached a few documents I gathered and prepared in this case. You do not need to vent AGMs if the larger space in which the battery enclosure is located has a typical and normal amount of natural air circulation and convective air exchange. Also, you can't duplicate what Kevin describes below with a vented enclosure - Kevin's approach requires a sealed and vented battery enclosure. By design, your enclosure is unsealed. Putting in vents for the next guy also makes no sense. If you install 8 flooded L16s on two shelves in a Midnite MNBE-Cl16 enclosure, you won't be able to routinely add water to the cells. The cabinet was designed and built for VRLA batteries. So any venting you install now would have to be redone to fit a cabinet built for flooded batteries
Re: [RE-wrenches] Sunny Island retrofit
Mac, that Island interconnects with a max 70A 1P breaker (6.7kW continuous), so unless they have a constant critical load draw or the Fronius is massively oversized, you probably don't want to AC couple the Fronius. The 5048 is also able to output a continuous 5000W only when it's cooler than 77F and it derates above that (4500W at 95F, for example). I don't believe its surge ratings apply to the AC2 output back into the utility but they probably wouldn't be enough, anyway. I think that whenever the Fronius output reached about 6000W, the SI would shift its frequency to switch the Fronius off. Cheapest may be along the lines of your first option-- not sure what the PV stringing is like but maybe you could move a string or two off the Fronius and put it onto a new Sunny Boy with an autoformer. Since I imagine this system doesn't have PV WIRE on the module leads or home runs, officially I'd recommend a classic Sunny Boy. Then leave the Fronius as-is. Unless of course the customer thought they were buying a system with the full 10kW supplying critical loads when the utility is down... then the original contractor is stuck with buying the second SI they should have installed in the first place. DKC On 2014/7/3, 10:46, Mac Lewis wrote: Hello wrenches, I wanted to run this scenario by the forum. I have spoken with SMA about this, but want some other opinions. We were recently contracted by a fellow solar company to do some warranty work for them out of town on a Sunny Island system that they had installed about 5 years ago. It was VERY poorly implemented originally and was never installed as SMA intended. In fact, during a small power outage, the only loads that never came back on after the utility was back on line were the loads in the critical load panel. Oops. Anyway, our job is to get it working properly for the least amount of cost possible. They have a Fronius IG Plus 10.0 fed into a 400A service panel. The Sunny Island 5048 AC Input also comes off of this panel and feeding a 120V only critical load panel. Please note that there is no solar fed into the AC output side of the Sunny Island, because there is not 120/240 available and thus there is no possible way for this system to utilize the solar while the grid is not present. I see two options (but there may be more): pull out Fronius, put in Sunny Boy inverters and an autoformer, wire properly. Another option is to add second Sunny Island and try to AC couple the Fronius with the two Sunny Islands. The second option is less expensive overall, but I'm hesitant to rely on AC coupling with the Fronius. I'd appreciate any thoughts on this. Thanks -- Mac Lewis * Yo solo sé que no sé nada. -Sócrates * ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] ASP Inverters
Jason, I think they were re-branded Eaton inverters. Unlike the modules, they were actually UL listed... On 2014/6/30, 16:13, Jason Szumlanski wrote: Does anyone know who manufactured the PV250 inverters from ASP before they went under? Are they private labeled inverters manufactured by others, or is ASP considered the OEM? I was able to find a manual online at least. Any experience out there with faults in these inverters? I have a feeling our first service call is going to be the first of many in our area. We're implementing a policy that we won't work on the inverters if the system has the fraudulent UL labels on the PV panels. That should be interesting... Jason Szumlanski Fafco Solar ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Rapid shutdown for pole mounts
Thanks to Nick for catching a misstatement in my email, corrected below in *bold*. I was trying to make a general statement out of his specific situation. On 2014/6/26, 10:20, Dave Click wrote: NEC says 10' from the array, defined as A mechanically integrated assembly of modules or panels with a support structure and foundation, tracker, and other components, as required, to form a direct-current power-producing unit. 70HB14_CH00_FM_pi_xii.pdf I take this to mean that the array definition includes support structure, so you could go 10' from the bottom of the pole? But that doesn't matter, as rapid shutdown requirements only apply to PV systems *[conductors]* on or in buildings; it only applies to a ground-mounted system if you bring the dc all the way into *or onto***a building (*if you are 10' from the array or 5' within the structure*). So, Rapid Shutdown doesn't apply at all to your scenario where only the ac wiring from a pole mount enters the building. DKC On 2014/6/25, 12:00, Jesse Dahl wrote: Re-reading this rapid shutdown convo. Does 10' from the array mean from the modules or the mount? What if the array is on a pole, the pole is 15' tall and the inverter is mounted at the base of the pole? Since the array (modules) is 15' from the inverter is rapid shutdown required? Again, since the title of 690.12 is On Buildings is it required for pole mounts where only AC enters the building? Thoughts? Thanks! Jesse On Sat, Apr 19, 2014 at 12:22 PM, Dan Fink danbo...@gmail.com mailto:danbo...@gmail.com wrote: Hi Aaron, boB, Wrenches; I think Aaron brings up a good point, and it's certainly confusing to me. The boldface type heading of 690.12 is Rapid Shutdown of PV Systems on Buildings The body of the 690.12 text begins with PV system *circuits* installed on or in buildings shall. 690.2 defines Photovoltaic source circuit as Circuits between modules and from modules to the common connection point(s) of the DC system and Photovoltaic output circuit as Circuit conductors between the PV source circuit(s) and the inverter or DC utilization equipment. PV system from the heading of 690.12 is not defined in 690.2, other than that the definition of Photovoltaic system voltage specifically includes both PV output and source circuits. To me the confusing part of 690.12 is PV Systems on Buildings is that system is not defined, and tends to imply rooftop arrays. But PV system circuits installed on or in buildings shall. is pretty clear. I interpret it to mean anything DC and PV stuck to the side of building like conduit, etc, or running insidewhich means it applies to ground-mount arrays too if they terminate outside or inside the building. What I'm seeing as the easy work-around for us off-grid folk is the old power shed idea containing battery bank, balance of system, inverter etcjust build it within 10 feet of the PV array and you're fine. Any thoughts? Dan Fink, Executive Director; Otherpower Buckville Energy Consulting Buckville Publications LLC NABCEP / IREC accredited Continuing Education Providers 970.672.4342 tel:970.672.4342 On Fri, Apr 18, 2014 at 3:30 PM, b...@midnitesolar.com mailto:b...@midnitesolar.com b...@midnitesolar.com mailto:b...@midnitesolar.com wrote: Bill Brooks should probably respond to this also, but reading the NEC, it looks like if the wires do not go inside the building to run more than 5 feet (as the crow flies), the the rapid disconnect does not apply.OR, less than 10 feet from the array IF the PV is mounted on that building. boB On 4/18/2014 1:34 PM, Aaron Mandelkorn wrote: The rapid shutdown language is so confusing. When looking at the rapid shutdown language, does PV systems on a building refer to only situations where the array is on a building; or does it include DC conductors as well. For example, if the DC conductors from a pole mounted array run up the side of a building before punching in to the inverter, does this require rapid shutdown? Is this PV system considered on a building? Aaron Aaron Mandelkorn Owner/Solar Specialist Renewable Energy Outfitters 719-221-5249 tel:719-221-5249 970-596-3744 tel:970-596-3744 www.reosolar.com http://www.reosolar.com reoso...@gmail.com mailto:reoso...@gmail.com ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi
Re: [RE-wrenches] Rapid shutdown for pole mounts
NEC says 10' from the array, defined as A mechanically integrated assembly of modules or panels with a support structure and foundation, tracker, and other components, as required, to form a direct-current power-producing unit. 70HB14_CH00_FM_pi_xii.pdf I take this to mean that the array definition includes support structure, so you could go 10' from the bottom of the pole? But that doesn't matter, as rapid shutdown requirements only apply to PV systems on or in buildings; it only applies to a ground-mounted system if you bring the dc all the way into a building (for at least a 5' run within the structure). So, Rapid Shutdown doesn't apply at all to your scenario where only the ac wiring from a pole mount enters the building. DKC On 2014/6/25, 12:00, Jesse Dahl wrote: Re-reading this rapid shutdown convo. Does 10' from the array mean from the modules or the mount? What if the array is on a pole, the pole is 15' tall and the inverter is mounted at the base of the pole? Since the array (modules) is 15' from the inverter is rapid shutdown required? Again, since the title of 690.12 is On Buildings is it required for pole mounts where only AC enters the building? Thoughts? Thanks! Jesse On Sat, Apr 19, 2014 at 12:22 PM, Dan Fink danbo...@gmail.com mailto:danbo...@gmail.com wrote: Hi Aaron, boB, Wrenches; I think Aaron brings up a good point, and it's certainly confusing to me. The boldface type heading of 690.12 is Rapid Shutdown of PV Systems on Buildings The body of the 690.12 text begins with PV system *circuits* installed on or in buildings shall. 690.2 defines Photovoltaic source circuit as Circuits between modules and from modules to the common connection point(s) of the DC system and Photovoltaic output circuit as Circuit conductors between the PV source circuit(s) and the inverter or DC utilization equipment. PV system from the heading of 690.12 is not defined in 690.2, other than that the definition of Photovoltaic system voltage specifically includes both PV output and source circuits. To me the confusing part of 690.12 is PV Systems on Buildings is that system is not defined, and tends to imply rooftop arrays. But PV system circuits installed on or in buildings shall. is pretty clear. I interpret it to mean anything DC and PV stuck to the side of building like conduit, etc, or running insidewhich means it applies to ground-mount arrays too if they terminate outside or inside the building. What I'm seeing as the easy work-around for us off-grid folk is the old power shed idea containing battery bank, balance of system, inverter etcjust build it within 10 feet of the PV array and you're fine. Any thoughts? Dan Fink, Executive Director; Otherpower Buckville Energy Consulting Buckville Publications LLC NABCEP / IREC accredited Continuing Education Providers 970.672.4342 tel:970.672.4342 On Fri, Apr 18, 2014 at 3:30 PM, b...@midnitesolar.com mailto:b...@midnitesolar.com b...@midnitesolar.com mailto:b...@midnitesolar.com wrote: Bill Brooks should probably respond to this also, but reading the NEC, it looks like if the wires do not go inside the building to run more than 5 feet (as the crow flies), the the rapid disconnect does not apply.OR, less than 10 feet from the array IF the PV is mounted on that building. boB On 4/18/2014 1:34 PM, Aaron Mandelkorn wrote: The rapid shutdown language is so confusing. When looking at the rapid shutdown language, does PV systems on a building refer to only situations where the array is on a building; or does it include DC conductors as well. For example, if the DC conductors from a pole mounted array run up the side of a building before punching in to the inverter, does this require rapid shutdown? Is this PV system considered on a building? Aaron Aaron Mandelkorn Owner/Solar Specialist Renewable Energy Outfitters 719-221-5249 tel:719-221-5249 970-596-3744 tel:970-596-3744 www.reosolar.com http://www.reosolar.com reoso...@gmail.com mailto:reoso...@gmail.com ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm
Re: [RE-wrenches] Racking System - Identification Help
As an update- the system used at this install turned out to be a currently-available product called SolAttach: http://www.solattach.com/ On 2014/6/3, 11:11, Dave Click wrote: Jason, thanks for the comment! I agree that systems could connect to just sheathing and stay on the roof- I think Zilla has a product that does this too. My concern about wind resistance stems from the fact that there appeared to be an engineer's stamp on the Unirac calcs with lag screws and then something completely different was installed in the field. It's likely that this installer has used this same mounting system in windier coastal areas so hopefully their fastener selection had some informed analysis... I didn't see any, though. And to be clear, I'm not looking to overrule another PE if it is in fact an engineered system and it's just that the wrong set of plans got submitted to the building department. DKC On 2014/6/3, 10:12, Jason Szumlanski wrote: Dave, I can't identify your hardware, but I just wanted to comment on your comment about hitting rafters. There are products out there that can obtain the requisite load ratings without connecting directly to structural members. We have had systems engineered and permitted using Ecofasten products on low-slope roofs that fasten only to wood sheathing or metal roof materials in 170 mph zones in Florida (ASCE 7-10, FBC 2010). I'm not an engineer, but I've been told if there is adequate data on pull-out and shear, you can use that data to properly design a system without hitting rafters with the right number of attachment points. I don't like the looks of what you pictured, but it's plausible that it was an engineered system design. The permit drawings not matching... that is another story... If, for example, each of the six fasteners provide 100 pounds of pullout strength with a safety factor, that would be good for 12 sq ft at 50 spf uplift per attachment. 250 fasteners would be good for about 5kW of solar. Jason Szumlanski Fafco Solar On Tue, Jun 3, 2014 at 9:06 AM, Dave Click davecl...@fsec.ucf.edu mailto:davecl...@fsec.ucf.edu wrote: Hi all, Anyone know what this racking system is? The permit drawings say Unirac with lag screws and Eco-Fasten flashings, which this pretty clearly isn't. I'd never seen this before, and I imagine this wind resistance is not quite the 140 mph that the installer claims it is. Of the ~250 wood screws holding this system down into the roof, I think six of them accidentally hit rafters. Thanks! Dave ___ List sponsored by Redwood Alliance List Address:RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive:http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Combining Multiple Inverters
Corey, The line of reasoning is faulty. It's 705.12(D)(1). Micro-inverters are the exception because they are specially listed to share a breaker. As for the other inverters, doubling them up on a single breaker / disconnect probably goes against their installation instructions [110.3(B)] and it's unlikely that you could put multiple units on a single breaker anyway because when you take (2 inverters) x (rated current) x (1.25) you will probably come up with a minimum breaker size that is larger than the maximum allowed under the NRTL listing to UL 1741. Dave On 2014/6/26, 16:18, Corey Shalanski wrote: We considered the necessity to shut down individual inverters and determined that the added costs of an inverter output combiner panel were not merited. I agree that in theory it seems beneficial to be able to switch each inverter individually, but how often does this occur in practice? For the relatively infrequent cases where we need to return to a jobsite and shut down an inverter - for troubleshooting/removal/etc. - we do not mind shutting down the other inverters (up to a limit) for what is hopefully a short period of time. Again, this whole line of reasoning may be shown to be faulty if someone can directly point to the Code section that requires OCPD on each individual inverter. -- Corey ? On Thu, Jun 26, 2014 at 9:20 AM, re-wrenches-requ...@lists.re-wrenches.org mailto:re-wrenches-requ...@lists.re-wrenches.org wrote: Message: 5 Date: Wed, 25 Jun 2014 19:17:57 -0700 From: William Miller will...@millersolar.com mailto:will...@millersolar.com To: RE-wrenches re-wrenches@lists.re-wrenches.org mailto:re-wrenches@lists.re-wrenches.org Subject: Re: [RE-wrenches] Combining Multiple Inverters Message-ID: 04f4b8fd-e280-4bf2-b5a4-c2fca8d1c...@millersolar.com mailto:04f4b8fd-e280-4bf2-b5a4-c2fca8d1c...@millersolar.com Content-Type: text/plain; charset=utf-8 Not allowed. You need a dedicated OCPD. Plus seems like a really bad idea. How do you shut down just one inverter? Miller Solar ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Racking System - Identification Help
Jason, thanks for the comment! I agree that systems could connect to just sheathing and stay on the roof- I think Zilla has a product that does this too. My concern about wind resistance stems from the fact that there appeared to be an engineer's stamp on the Unirac calcs with lag screws and then something completely different was installed in the field. It's likely that this installer has used this same mounting system in windier coastal areas so hopefully their fastener selection had some informed analysis... I didn't see any, though. And to be clear, I'm not looking to overrule another PE if it is in fact an engineered system and it's just that the wrong set of plans got submitted to the building department. DKC On 2014/6/3, 10:12, Jason Szumlanski wrote: Dave, I can't identify your hardware, but I just wanted to comment on your comment about hitting rafters. There are products out there that can obtain the requisite load ratings without connecting directly to structural members. We have had systems engineered and permitted using Ecofasten products on low-slope roofs that fasten only to wood sheathing or metal roof materials in 170 mph zones in Florida (ASCE 7-10, FBC 2010). I'm not an engineer, but I've been told if there is adequate data on pull-out and shear, you can use that data to properly design a system without hitting rafters with the right number of attachment points. I don't like the looks of what you pictured, but it's plausible that it was an engineered system design. The permit drawings not matching... that is another story... If, for example, each of the six fasteners provide 100 pounds of pullout strength with a safety factor, that would be good for 12 sq ft at 50 spf uplift per attachment. 250 fasteners would be good for about 5kW of solar. Jason Szumlanski Fafco Solar On Tue, Jun 3, 2014 at 9:06 AM, Dave Click davecl...@fsec.ucf.edu mailto:davecl...@fsec.ucf.edu wrote: Hi all, Anyone know what this racking system is? The permit drawings say Unirac with lag screws and Eco-Fasten flashings, which this pretty clearly isn't. I'd never seen this before, and I imagine this wind resistance is not quite the 140 mph that the installer claims it is. Of the ~250 wood screws holding this system down into the roof, I think six of them accidentally hit rafters. Thanks! Dave ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] SMA, Flexible stranded Connectors, Sleep Deprivation
This may be useful: http://www.cobrawire.com/lugs/lugs.php?cat=xflex On 2014/4/30, 14:25, William Miller wrote: Ray: Thanks for sharing the research. If you could forward to me of-line an email contact and part number I need to order for 4/0. Miller Solar On Apr 30, 2014, at 10:22 AM, Ray Walters r...@solarray.com mailto:r...@solarray.com wrote: What I'm finding in my research is that most of the manufacturers are just not keeping up with this requirement, meanwhile the use of fine stranded cable is increasing dramatically. ILSCO, BURNDY, and Quick Cable all barely mention fine strand ratings. I have their catalogs in hand. Even the SMA manual does not mention this issue, I had to call tech support. BTW, there appears to be some big name integrators just using flex cable directly. Meanwhile, I can share a pic of the one lug I torqued down, and didn't like, which lead to all this: Little copper hairs tearing, or not part of the connection at all. How did we survive the 90s stuffing welding cable into Heinemann breakers in Trace DC boxes? Also, when you go into major Electrical suppliers that sell the flex cable, and ask if the connectors are rated for fine stranding, all you get is that deer in the headlights stare. I was used to having to figure all this out in the old days of solar, but now that every electrical supplier in town is claiming to be a solar expert/ distributor, I really should be able to just walk in and get the parts I need for a Code compliant installation. If you sell the inverter and the cable, you really should stock the connector. On another note, the ferrules/ sleeves seem to be the ticket, as confirmed by Schneider. Also they appear to be 40 times cheaper than pin adapters, and don't take up extra room in the wiring compartment. Now I just have to find some TODAY. Ugh... And like Allan, I lost sleep over this issue last night. R.Ray Walters CTO, Solarray, Inc Nabcep Certified PV Installer, Licensed Master Electrician Solar Design Engineer 303 505-8760 On 4/30/2014 10:38 AM, Glenn Burt wrote: There are many available lugs that are listed for use with finely stranded conductors - this is not an excuse to not use the proper lugs and required equipment to ensure a safe and reliable installation (per the NEC). Thomas Betts is the manufacturer I use. Indeed the tool is pricey, however it is necessary to produce a compliant installation (per 110.3(B)). -Glenn -Original Message- From:re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of jay peltz Sent: Wednesday, April 30, 2014 10:09 AM To: RE-wrenches Subject: Re: [RE-wrenches] Flexible stranded Connectors Hi ray As an FYI. Most of the lugs we all use are not rated for fine stranded wire. Quick cable is the only one I'm aware of that if you use their tool and ends says its UL for fine stranded. I prefer ferrules for those applications vs pin adapters. (Schneider XW inverter BOS box comes with arctic ultra flex wire with ferrules) Jay Peltz power On Apr 29, 2014, at 10:48 PM, Ray Waltersr...@solarray.com wrote: Hi All; In order to avoid any of my work showing up in someone's slideshow of horrors, I'm trying to find the correct way to wire 3 Sunny Islands with Cobra X flex cable. While it doesn't actually mention it in the SMA manual, a call to SMA tech support confirmed my suspicions: the DC lugs in the inverter are NOT rated for flex or fine stranded cable. Both SMA and CED recommended I try Grainger's for crimp on adapters. Grainger had no clue, and nothing came up in searches there. From a trade show, I have an ILSCO lug book, that shows a crimp on pigtail adapter. It does not mention whether its flex rated though on the crimp side of the adapter, as the adapter is used primarily to land over sized cables into smaller lugs. (2/0 to #1, for instance) The best I've found so far, is NSI, which makes sleeves, that are installed around the wire, right in the connection: http://www.nsiindustries.com/products/electrical/connectors/compressio n-connectors/copper-compression/fsflex-cable-sleeve.aspx I also found a Schneider white paper recommending sleeves with their lugs: http://static.schneider-electric.us/docs/Circuit%20Protection/0515DB03 01.pdf So who has used these sleeves, and where do I get them? The sleeves seem like a decent compromise, whilst the ILSCO pigtail adapters are coming in at $40/ ea.. (ouch) On the internet, I'm seeing several examples of X flex used directly (no adapters) with the Sunny Islands, so are folks just blowing off articles 690.31(F) and 110.14, that specify the connector be rated for flex cable? And finally, couldn't SMA use a lug that was flex rated? For example, Marathon makes Class K rated mechanical Lugs: http://www.marathonsp.com/NewRatings.html I'd use THHN, but I really don't feel good about wiring the Heineman breakers with that stiff a wire. I've cracked breaker
Re: [RE-wrenches] Article 690, or The Haves Vs. Have Nots
I think 240.24(A)(4) allows the installation of the inverter OCPDs in the SolaDeck hidden under a module. ** *240.24 Location in or on Premises.* ** National Electrical Code 2008 Edition *(A) Accessibility.* Overcurrent devices shall be readily accessible and shall be installed so that the center of the grip of the operating handle of the switch or circuit breaker, National Electrical Code 2008 Edition when in its highest position, is not more than 2.0 m (6 ft 7 in.) above the floor or working platform, unless one of the following applies: ... (4) For overcurrent devices adjacent to utilization equipment that they supply, access shall be permitted to be by portable means. And if panelboards / fused safety switches are allowed to have screwed-down covers over the OCPDs, I'd think that installing a removable module over these OCPDs would meet NEC. I guess an AHJ could argue that this requires TWO covers be removed, unlike a panelboard or a switch. DKC On 2014/4/29, 11:15, Jason Szumlanski wrote: 690.9(D) is not applicable to the original discussion because we were talking about an Inverter output circuit, not a PV Source or Output circuit. 690.34 may apply if you call a SolaDeck with breakers a junction box, but I can see that being a stretch in the mind of many. My and Ray's question about the screws on the SolaDeck cover itself requiring a tool to render it accessible is still an issue if the breakers themselves need to be readily accessible, but that would also apply to a Midnite MNPV, which also has a cover with a screw. Jason Szumlanski On 4/28/2014 5:57 PM, Bill Brooks wrote: Read 690.9(D) and 690.34. Not sure where this hysteria---run for the border sentiment is coming from. *690.9(D) Photovoltaic Source and Output Circuits. *Listed PV overcurrent devices shall be required to provide overcurrent protection in PV source and output circuits. The overcurrent devices shall be accessible but shall not be required to be readily accessible. *690.34 Access to Boxes. *Junction, pull, and outlet boxes located behind modules or panels shall be so installed that the wiring contained in them can be rendered accessible directly or by displacement of a module(s) or panel(s) secured by removable fasteners and connected by a flexible wiring system. This is not a change. Please help me understand the concern. Bill Brooks. *From:*re-wrenches-boun...@lists.re-wrenches.org mailto:re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *Ray Walters *Sent:* Monday, April 28, 2014 2:23 PM *To:* RE-wrenches *Subject:* Re: [RE-wrenches] (no subject) Interesting so does require a tool include taking a screw off the cover plate of the combiner box, too? What a game changer. I'm going to Mexico for my next project; I'll actually enjoy even more being the sole AHJ on the project. R.Ray Walters CTO, Solarray, Inc Nabcep Certified PV Installer, Licensed Master Electrician Solar Design Engineer 303 505-8760 tel:303%20505-8760 On 4/28/2014 2:52 PM, Michael Morningstar wrote: Readily accessible is now defined in the 2014 NEC. Installing OCPD's underneath a module is a major faux paux, and I can't imagine any AHJ thinking otherwise. Having to remove a module in order to reset a breaker, what a drag. Capable of being reached quickly for operation, renewal or inspection without requiring those concerned to use a tool, to climb over, remove obstacle or other. Michael On Apr 28, 2014, at 10:29 AM, William Miller will...@millersolar.com mailto:will...@millersolar.com wrote: You call it a solar panel, I call it a glass j-box cover plate. William Miller Solar On Apr 28, 2014, at 9:21 AM, Jason Szumlanski ja...@fafcosolar.com mailto:ja...@fafcosolar.com wrote: If that is the interpretation, I don't see how the breakers are readily accessible in a SolaDeck mounted anywhere, regardless of whether it is under a module. It requires removal of four screws (using a tool) to access the breakers inside the enclosure. It's all up to the AHJ. It has not been an issue locally here. I can see how other jurisdictions may not concur. ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
Re: [RE-wrenches] NEC 2014 690.12 Rapid Shutdown
Nathan, 690.12 only applies to PV system circuits installed on or in buildings so that might be your answer. You'd only be affected by 690.12 if you're running to an interior inverter. So- your strategy of exterior conduit to wall-mounted inverters on the exterior of a building won't be subjected to the 690.12 requirement. On 2014/4/15, 11:09, Nathan Charles wrote: Hi All, I have a follow up to this discussion. What's the proper way to think through this regarding ground mounts? It seems to me that if the goal is to protect firefighters then running a conduit underground and coming up to outdoor wall mounted inverters is keeping in the spirit of things, but I'm not sure if the language of 690.12 supports this. Am I mistaken? Do you have any best practice advice for this scenario? Best regards, -N On Tue, Jan 21, 2014 at 12:36 PM, Drake drake.chamber...@redwoodalliance.org mailto:drake.chamber...@redwoodalliance.org wrote: Bill, It is good to see that energized conductors are going to be disconnected near the arrays. I've been an advocate of disconnecting these conductors by ground fault sensing equipment since ground fault detection was first implemented in the code. If contactors are to be installed on roofs, it likely won't be long before both ground faults and arc faults are automatically cleared. When the requirement for AC arc fault branch circuit protection was first put in the NEC, it was postdated to allow time for the electrical industry to adapt. This new remote disconnecting requirement does not provide any lead time. As the 2014 NEC is adopted in various jurisdictions, inspectors may feel that it is necessary to disallow systems without the newly required disconnect feature. This may result in serious problems for solar companies and customers, as well as manufacturers. The protection of firefighters is essential. The implementation of renewables is essential also. Insurance claims for weather related, global warming-triggered climatic disasters are rising exponentially. Extreme weather related events result in major loss of life and billions of dollars in property damage. Atmospheric CO2 levels continue to climb from the burning of fossil fuels. This is a crisis of global proportions. My request for code writers is to please take into account the effect that inserting new rules into the NEC may have on the stability of renewable energy, and implement new requirements in a way that will allow for a smooth interface. Thank you, Drake Drake Chamberlin /Athens Electric LLC OH License 44810 CO License 3773 NABCEP Certified Solar PV 740-448-7328 tel:740-448-7328 /http://athens-electric.com/ At 12:45 PM 1/16/2014, you wrote: Content-Type: multipart/alternative; boundary==_NextPart_000_0F94_01CF129F.BCC65BD0 Content-Language: en-us Jeffrey, Sounds like you need to get involved in the code making process since you have so many good ideas on how to improve the language. I like confrontational discussions as long as they lead to a better understanding and constructive outcomes. About 30 people worked on this language, so it is definitely not perfect. However, I don't think it is quite as bad as you make it out to be. I wanted to jump in since some of your conclusions were not correct. This is a circuit requirement, not a disconnecting means requirement, since it has to do with shock hazard of PV circuits in and around a building. This is for firefighter safety. 30V is the international standard for touch safe in a wet location. 240VA is to set a limit on the available power on a circuit. Contactor combiners, which would be part of a compliant solution, have 24V control circuits. The other reasoning for 240VA is that internally, 72-Cell PV modules can be divided into segments of this power level for the foreseeable future (more on that another day). If the conductors stay outside, you have 10' from the array to place your shutdown device. On large central systems, this would likely be a contactor combinermost manufacturers sell these. If the conductors are going immediately into the building, as with residential and integrated systems, a shutdown device would have to be within 5' of entering the building. If goes outside for a while, then inside the building, the total length could be no more than 10' and no more than 5' inside the buildingthis is not additive. Remember, all this is for firefighter safety. As Brian Mehalic and others have pointed out, the language does not specify where the shutdown initiating device is to be located. The lack of detail is more for flexibility than it is to give an AHJ license to make an installer do anything they want. With grid-tie only
Re: [RE-wrenches] Myths, Schemes and Scams request
If you also have the local electricians selling the kvar units as surefire ways to save 30% on your electric bill, I'd nominate that as myth/scheme/scam, though I hope most of those resellers are doing so only because they're naive. There was also some absurd company a few years ago which was selling a 3000W module that looked suspiciously like a 200W module yet could produce a steady 3kW even without any load and even while in the shade. They had the clamp-on meter to prove it, so maybe they're still selling off area code exclusivity off for a mere $50,000 initial deposit. Screen-shots from this would be fun-- one of the ubiquitous $50 for this complete guide to unplugging from grid by making your own solar panels http://www.powerfreedom.com/System/ The YellowBook ad from a few years ago: https://www.youtube.com/watch?v=6hpHxEhO_DQ I don't know where I got this picture-- from one of the make your own solar panel things online. Lovely aesthetics! https://www.dropbox.com/s/bxhl3q6hrr9z5sp/DIY%20PV.png On 2014/4/12, 16:47, Allan Sindelar wrote: Fellow Wrenches, Last year I prepared an hour's presentation for our local Solar Fiesta on Energy Myths, Schemes and Scams. I covered mostly PV and the solar industry, with a few slides about the physics of wind and those cute spinny yard-art things called VAWTs. I also hit on it takes more energy to make a PV panel than it will ever produce, the limitations of 25-year module warranties, free energy generators, James McKirdy, lunar modules, and modules with fraudulent listings. This was what I was able to pull together. The workshop was popular and I have been asked to give it again in a couple of weeks. I'm looking for any suggestions that you may have for new or additional material to update the presentation. Any ideas are welcome, especially if you can provide links to good stories and slide materials. This is for a general non-technical audience, but I have the freedom to go in any direction I wish. So I'd like to be more than just entertaining, but make points about value over price, using local installers with knowledge and experience, etc. Beside my appreciation for the material, I'll offer in return to share an editable version of the presentation for your own use (although it's a 14 meg PowerPoint file at present). Thank you in advance for your suggestions of anything that gets your blood boiling, that would be funny if it wasn't giving PV and clean energy a bad name. Allan -- *Allan Sindelar* _Allan@positiveenergysolar.com_ mailto:al...@positiveenergysolar.com NABCEP Certified PV Installation Professional NABCEP Certified Technical Sales Professional New Mexico EE98J Journeyman Electrician Founder (Retired), *Positive Energy, Inc.* A Certified B Corporation^TM *505 780-2738 cell* ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Fault Current
Karl, you're interconnecting into a spot/area network, right? It's a real concern; some solutions and background on the issue here: http://www.nrel.gov/docs/fy09osti/45061.pdf DKC On 2014/3/27, 14:05, Karl Jaeger wrote: Esteemed Wrenches, We've recently run into an issue with a local distributor citing network fault current on a split-phase service as a reason to prevent interconnection of our customer's solar array. They've given us the options of reducing our system size from 36.5kW-DC to 15kW-DC, or having the customer upgrade to 3-phase at a soft price of $20-30K. We're looking at 32kW of inverters on a 167kVA transformer. Does anyone have experience on circumventing the issue of network fault current? Any experience with Fault Current Limiters? Much appreciated, *Karl Jaeger* *Design/Build Engineer* *LightWave Solar Electric LLC* ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Busbar 120% rule
I had a nice response all typed up before rediscovering my original source. Simple answer: there's still a thermal load to deal with even though there's no point on the bus seeing a current above the busbar rating. I am a linking machine today: http://www.nmsu.edu/~tdi/Photovoltaics/Codes-Stds/690.64(B)(2)Load%20Side%20Connections.pdf /While this situation of connecting supply overcurrent devices at opposite ends may be // //safe for restricted conductors, it may not be suitable for busbars in panel boards, even // //though this allowance is in the 2008 NEC. Panel boards are subject to busbar current // //limitations and are also subject to thermal limitations due to the heating associated with // //the thermal trip elements in the common thermal/magnetic molded case circuit breakers. // //For example a 100-amp, 120/240V panel board is tested during the listing process with a // //100 amp main breaker and two 100-amp load breakers (one per phase) mounted directly // //below the main breaker. The ambient temperature is raised to 45 degrees Celsius, the // //input and output currents are set at 100 amps, the temperature is allowed to stabilize, // //and the panel must pass this test with no deformation of any parts. If we add a backfed // //PV breaker pair, for example 50 amps, at the bottom of the panel, and if the loads on the // //panel were increased to 150 amps, no breakers would trip, no busbars would be over // //loaded, but the thermal load in the panel would be that associated with 300 amps, not the // //200 amps the panel was designed and listed for. Panel manufacturers have stated that // //these panels cannot pass UL listing tests with those excessive thermal loads./ On 2014/3/27, 14:34, Troy Harvey wrote: I am wondering about the busbar 120% rule, and if there is any wiggle room in the 2014 NEC. Fundamentally I don't understand the 120% rule. If my solar breaker is installed properly at the bottom of the busbar, and the grid-tie breaker is installed at the top, and the busbar itself is rated for 120% of the panel rating, I don't see any means by which a solar breaker of a size substantially larger than 120% could cause a problem. There can be no place on the busbar under any situation (that I can think of) that would exceed 120% because the supply current is coming from opposite ends of the bus bar - even in the worst case load situation. So even if I had a huge PV system (100A), backfeeding the bottom of a 200A panel, I don't see a situation where there is more than 200A over any one section of busbar. Am I wrong, or is the NEC just too prescriptive for its own good? Also would you say that the 120% is based on the inverter max output or backfeed breaker size? thanks, Troy Harvey - Principal Engineer Heliocentric 801-453-9434 tahar...@heliocentric.org mailto:tahar...@heliocentric.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Fault Current
The explanation you quote doesn't make any sense to me. If the engineer is concerned about fault current, the primary source is going to be through the utility transformer, and it will be on the order of 5,000 - 10,000A depending on the transformer's impedance. The fault current contribution from the inverters will be much less than that (an SB8000 fault current is all of 61.7A) and it will last for a much shorter duration. Be nice-- some engineers think by default that all generation acts like a rotating machine, which can contribute quite a bit of fault current. Not so for PV, so hopefully this engineer will see the light with a bit of help from you. A few questions for your engineer then: 1) These inverters will be exporting power, not drawing it; why are the inverters not considered a negative load in this installation? [I assume you're not installing batteries] 2) What is the 500A fault current limit that was taken into account in the site design? The service size is ___A. A 167kVA transformer at 240V has a rated current of about 700A, which is another reason why the 500A fault current doesn't make sense. DKC On 2014/3/27, 15:28, Karl Jaeger wrote: Nathan, The only explanation the electrical distributor provided is seen below. They are really skirting a thorough explanation... /The distributor engineer does not view the inverters as a negative load, and states they will exceed the 500A fault current limit the site is designed for./ Thanks, Karl *From:*re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *Nathan Charles *Sent:* Thursday, March 27, 2014 2:03 PM *To:* RE-wrenches *Subject:* Re: [RE-wrenches] Fault Current Karl, Can you give us some more details on their concerns? I've done some very large single phase ag installs and the only time I've had issues is when we exceed the 80% of minimum load on the medium voltage feeder. Best, -N On Thu, Mar 27, 2014 at 2:51 PM, Karl Jaeger kjae...@lightwavesolar.com mailto:kjae...@lightwavesolar.com wrote: Dave, We are about as rural as we can get here farm land. Very good document, nonetheless. Karl *From:*re-wrenches-boun...@lists.re-wrenches.org mailto:re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *Dave Click *Sent:* Thursday, March 27, 2014 1:29 PM *To:* re-wrenches@lists.re-wrenches.org mailto:re-wrenches@lists.re-wrenches.org *Subject:* Re: [RE-wrenches] Fault Current Karl, you're interconnecting into a spot/area network, right? It's a real concern; some solutions and background on the issue here: http://www.nrel.gov/docs/fy09osti/45061.pdf DKC On 2014/3/27, 14:05, Karl Jaeger wrote: Esteemed Wrenches, We've recently run into an issue with a local distributor citing network fault current on a split-phase service as a reason to prevent interconnection of our customer's solar array. They've given us the options of reducing our system size from 36.5kW-DC to 15kW-DC, or having the customer upgrade to 3-phase at a soft price of $20-30K. We're looking at 32kW of inverters on a 167kVA transformer. Does anyone have experience on circumventing the issue of network fault current? Any experience with Fault Current Limiters? Much appreciated, *Karl Jaeger* *Design/Build Engineer* *LightWave Solar Electric LLC* ___ List sponsored by Home Power magazine List Address:RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive:http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm http://www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org http://www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm http://www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org http://www.members.re-wrenches.org -- Nathan Charles Engineer NABCEP Certified PV Installation Professional #042013-20 Paradise Energy Solutions (717) 283-2021 direct ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re
[RE-wrenches] 1000V System Wiring Details
Hi Wrenches- If you're installing 1000V systems, are you running continuous PV WIRE all the way to your inverters? If not-- what splices have you found (aside from MC4s and similar) that are listed for 1000V? And when transitioning from PV WIRE to a cheaper conductor, what 1000V options exist beyond USE-2? Thanks! Dave ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] NEC 690.10(C) talking points
Dan, 690.10(C) doesn't say no. It says that if you have a single 120V inverter output connected directly for a 120/240 panel then you can't put a 240V load in the panel-- in this case you'd either have L connected to both phases of the panel or I guess you could just use half the breakers in the panel. For a 240V load it would just see 0 volts phase to phase, but for a multi-wire branch circuit with current on both legs you'd potentially overload your neutral conductor. Now when you use either a 240V inverter (or two stacked 120s) or an autotransformer between the inverter and the panel, 240V loads are fine since you have two lines 180 degrees out of phase and voila, 240V. 690.10(C) wouldn't apply to this situation since your inverter(s) would be supplying 240V (not 120) to your 1P 3W panel. DKC On 2014/3/19, 20:40, Dan Fink wrote: Esteemed Wrenches; Can anyone here help me with some simple talking points for clients installing off grid systems? 240 Well pumps hard wired to panel breakers are common, but everybody (who has even a chance of surviving up here in middle of nowhere way off grid) NEEDS a 240v welder outlet in the garage/workshop. But 690.10(C) says no. Am I missing something obvious? What do I tell these potential clients? Dan Fink, Executive Director; Otherpower Buckville Energy Consulting Buckville Publications LLC NABCEP / IREC accredited Continuing Education Providers 970.672.4342 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] DC Fusing/Breakers for Battery Circuits
All, I think that in the past, list discussions have talked about fusing of parallel battery circuits as a best practice, but it's required per 690.9 right? (text below from 2008 NEC) Also, if someone (don't look at me) really wants to use 2 parallel circuits of 12V batteries, what equipment is recommended to provide overcurrent protection? The installer is using Outback hardware (FW500?) and has two battery circuits combined in the battery enclosure and run to a Big Bus feeding the two 125A dc disconnects for two GVFX3648s. If you've read this far, this area is more your wheelhouse than mine. Thanks in advance! 690.9 Overcurrent Protection (A) Circuits and Equipment. Photovoltaic source circuit, photovoltaic output circuit, inverter output circuit, and storage battery circuit conductors and equipment shall be protected in accordance with the requirements of Article 240. Circuits connected to more than one electrical source shall have overcurrent devices located so as to provide overcurrent protection from all sources. Exception: An overcurrent device shall not be required for circuit conductors sized in accordance with 690.8(B) and located where one of the following apply: (a) There are no external sources such as parallel-connected source circuits, batteries, or backfeed from inverters. (b) The short-circuit currents from all sources do not exceed the ampacity of the conductors. ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Best Ground Racking?
A colleague found this online the other day as one potential option for shielding the wires for a ground-/pole-mount system: http://www.solarscrim.com/index.php No personal experience, though. Looks like they may ship with black zip ties but Sunbundler ties (or others) would be an easy swap. Didn't notice that REC residential/AEE had been sold. It looks like SolarCity, Vivint, and Sunrun are just taking turns buying every smaller solar company to make sure that the others don't get them. On 2014/2/4, 23:47, will...@millersolar.com wrote: Kelly: Ground mount racking choice is determined on a case-by-case basis. If the ground is flat and area plentiful, we use ballasted on gravel (Dyno-Raxx). If you need to seasonally adjust, we like the DPW MPM. If the ground is sloped other than gradually south, top of pole mounts may be your choice. For flat ground, low tilt (grid-tied) fence post arrays like the DPW LGM work well. For high wind areas, consider the DPW TTRGM on piers spanned by strut. Lest anyone think I am the cheering section for DPW, I suggest you avoid the DPW P6 or P8 Tilt Kit assemblies. The brackets are flimsy. Also, avoid DPW's L-feet. They are bent aluminum and come pre-stress cracked at no extra cost. For L-feet, use Unirac Serrated L-feet. It is refreshing to hear someone ask about wire management upfront. All too often this is an afterthought. In the industry vacuum we have been developing wire management systems on an ongoing basis. Below is a link that depicts some of our ideas. http://www.millersolar.com/public_html/MillerSolar/practices/PV_wiring/_PV_Wiring2.html The Code now requires wire shielding on readily accessible PV which means ground mount. Just managing the wire is not enough, you must shield it from touch. One option is to enclose the PV in chain link, which ramps up the ugly factor (I don't think three rail pasture fence or even barbed wire complies). Once you fence the array you can dispense with shielding, but you still don't want the leads dangling in a year or two, so avoid any flavor of plastic wire ties. There have been studies proving they don't last (US Navy is one source). We have looked at racking members with larger interior cross section (i.e. Pro-Solar) with the intent of running AC and DC leads inside and we have even mocked up a few, but fitting leads and the proprietary nuts into the same channel has proven impractical. Good luck. William Miller PS: Speaking of racking systems, did anyone get the news that SnapNRack and indeed the entire REC Residential juggernaut has been sold? Read the rest of this story http://r20.rs6.net/tn.jsp?f=001DOU7toids4P6EbtZ8amZnWIPqfwSVSQprZxgWcCDNMwVujGRFeNr6kDDQxv8reDLHOjQsU5ZAbim7nwyi2LH1WCwpxjpydyrqtwAXR7rGEE1Vv9y6CHdApOn8xu7viO-boKxfR0vxuRWZuQZUsi31k7EuNfvsnYtZxiDLh9hiU2snspkUXkwVWlu0bEQXhPr6iN048ijV9vyy42Nc0lSkRY8eR4Vuhj1x9WG_J42Nw3BUMy2LRo8bPk83rGlFxOIi3a3_xZ86ubEYbyk1MwQDdKVfXOrZiplaNIIzrDh6n_xz1PO28GP4feFeQCk2gd8l_yy_pAgMdOHcKD_IDW7y6eRVPj8LA5FS7-3nIgC4egIz2vMLcdeRCtjg_WNZoRohptTtbcFtULUCOupqpn91wIENm--baFFvHj0TycL7wMKVBZI340LaA==c=-PYi8jywk0XKsL2vpOkRGCzs2UwO52AqIXjyxYLdwi6HgzYpVBBpKQ==ch=UHlwvhDu_eij1qcoWtW5qiGLvNITtkXGLCqG4RSjo4k9OQWUYTpu8w== Wm On Feb 4, 2014, at 4:45 PM, Kelly Larson solarwre...@asis.com mailto:solarwre...@asis.com wrote: Thanks, Aaron. How are you handling wire management and connection to the ground? Blessings, Kelly On Feb 4, 2014, at 2:41 PM, Aaron Mandelkorn wrote: I like SnapNrack 200 Series as well as DPW Solar Multi Pole Mount. On Feb 4, 2014, at 3:28 PM, Kelly Larson solarwre...@asis.com mailto:solarwre...@asis.com wrote: Hi, We are looking to install some 4KW ground mounted arrays. What racking are you using? Best ground connection? Wire management? The shows have so many choices, and I keep doing the same ol thing... Blessings, Kelly Kelly Larson Electrical Engineer NABCEP Certified Solar PV Installation Professional IREC Certified Master Trainer CA Electrical Contractor# 868189 SolarKelly.com http://solarkelly.com/ ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm
Re: [RE-wrenches] (RE-wrenches) 2x200 amp meter main panel question
I would think this would be fine, so maybe I am missing the issue. Does CA have a state-specific rule on this? What you're asking is whether you can safely install a 40A inverter circuit in each of your interior [200-225A] panelboards fed from this meter main, right? This is two separate load-side interconnections, one per service disconnect. DKC On 2014/1/23, 15:30, William wrote: John: These panels are typically rated only 320A continuous duty, so I think your numbers would not compute. William On Jan 23, 2014, at 11:31 AM, John Powell a...@solforce.com wrote: Has anyone tried to connect one 40 amp inverter output circuit to each of the two breakers on a 2 x 200AMP single meter main panel in California? ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] NEC E-Book Access
Has anyone checked out the NEC in Enhanced E-Book form? Is it worth buying rather than the PDF? I'm guessing that the E-Book format cripples it and makes it incredibly annoying to use, but figured I'd ask. Thanks- have a great weekend all. DKC ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Individual DC conductors through separate conduits
** *300.3(B) Conductors of the Same Circuit.* All conductors of the same circuit and, where used, the grounded conductor and all equipment grounding conductors and bonding conductors shall be contained within the same raceway, auxiliary gutter, cable tray, cablebus assembly, trench, cable, or cord, unless otherwise permitted in accordance with 300.3(B)(1) through (B)(4) [which don't help here]. National Electrical Code 2008 Edition On 2013/11/19, 12:38, August Goers wrote: Hi All -- On a related note, I've become good friends with some of the inspectors in San Francisco and they called me yesterday with a question. Is it okay to run _individual_ DC conductors through EMT for wire management purposes? We have always run paired positive and negative conductors in conduit so the question had never occurred to me. Obviously, you have to bond both ends of the conduit if it is over 250 v. I know that AC would have induction issues with running individual conductors but I'm not sure with DC. Thanks, August August Goers Principal Luminalt Energy Corporation o: 415.641.4000 m: 415.559.1525 www.luminalt.com http://www.luminalt.com *From:*re-wrenches-boun...@lists.re-wrenches.org mailto:re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *William Miller *Sent:* Monday, November 18, 2013 11:33 PM *To:* 'RE-wrenches' *Subject:* Re: [RE-wrenches] PV Wiring methods Bill: There is no need to stuff MC4 cables into standard conduit. You can either slot the pipe using our easy method or install bulkhead type connectors. The connectors are readily available. I get them from PV Cables in Northern California.. Wire routing problems and some solutions can be found on our web-site: http://millersolar.com/MillerSolar/practices/PV_wiring/_PV_Wiring2.html Since the industry won't provide wire management solutions, we are making our own. Questions: Just write or call. William Miller *From:*re-wrenches-boun...@lists.re-wrenches.org mailto:re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *frenergy *Sent:* Thursday, November 14, 2013 7:46 AM *To:* RE-wrenches *Subject:* Re: [RE-wrenches] PV Wiring methods William, Billfrom another Bill, Two things: For the rest of us (maybe it's just me?!) that's still trying to figure out how (or why) to stuff a MC4 connector into conduit and my hesitation in using SS wire ties for fear of the sharp edges cutting or chaffing into cables, I'm open for advice. Any wire I use on the roof is rated for that type of service and I have some off-grid systems that have been in the sun for some 25 years where the wire still looks nearly new even when flexing it to look for checking/cracks. It seems the wire/insulation can take it, thus it seems like the key to wire management is to keep the wire from moving and off the roof, secured to the racking, thus not compromising the insulation. ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] SunBandit Hybrid Solar Water Heater
There are similar systems available to this one. I think you mean that the inverter is UL 1741, but the system is not grid-interactive. Stand-alone inverters can be listed to 1741 as well. IIRC, when I saw them at SPI 2012 they were doing everything in DC. They may have switched to AC so they could use romex rather than EMT? On 2013/10/3 16:13, Jason Szumlanski wrote: Anyone else getting inundated with SunBandit Hybrid Solar Water Heating System marketing emails? Any first impressions? Here are my initial thoughts: Pros - provides hot water in utility outages, no interconnection hassles, possibly easier permitting hurdles, eliminates moving parts in active SDHW systems Cons - no grid-tie, any excess energy produced is wasted, AHJs won't know how to categorize equipment for permitting and may charge for solar water heating and PV permits and inspections I haven't dug too deep, but one strange thing I think I saw on a spec sheet was that the micro-AC Grid (aka microinverter) is UL 1703. If that is the case, how does the PV continue to provide water heating in a utility outage? What I really don't understand is why there is a need for a microinverter at all? Why not just use a DC element? I guess a microinverter, despite minor efficiency losses, is cheaper than a load controller. Jason Szumlanski Fafco Solar ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] PV Temp Comp calculations
William, for quick estimates I usually use www.pvselect.com which uses high ambient+30C for its VMP calcs. On 2013/9/27 1:01, William Miller wrote: Friends: Do any of you know any good, on-line tools for calculating temperature compensated string voltages? I looked but I can't find one. I have found some good articles on the subject... Lacking one, I created an Excel spreadsheet. I am no expert in this aspect of design so I am using it cautiously. If anyone wants to check it out, here is a link. Any feedback is appreciated: http://www.millersolar.com/MillerSolar/Resources/_PV_String_calculator.xls As always, thanks to all of you for the excellent input. William Miller ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] 3-Phase Service, One Phase Fails
Eaton just announced some safety switches with shunt trip that may work for you- Google: Eaton TD008003EN to get the datasheet. TD008003EN On 2013/9/24 11:12, Karl Jaeger wrote: Greetings Esteemed Wrenches, We are building a 35.75kW project with (6) Power One 6000's. The service is a 240 delta. The utility is requiring (late in the game) that if one leg of the service is lost, all inverters must shut down. Of course, we have two inverters that do not shut down in that circumstance because they are only tied into the other two phases. SMA has a good (cheap) option to deal with this, SMA Power Balancers. With other inverters this can be accomplished by installing an ATS with an integrated controller by programming in the unacceptable phase imbalance (expensive). Does anyone have experience with this requirement and/or have a good (cheaper) solution? Thank you in advance! Karl Jaeger LightWave Solar Nashville, TN ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] GEC sizing for a high amp, low voltage PV system with microinverters
I think Gary may be overthinking this. If the micro-inverters have a GEC lug then you'll need to run a GEC. If you run your GEC to a ground rod, then you don't need to use one larger than #6 per 250.166(C). (note also (D) and (E) but they're less useful to you here) / Commentary:/ It makes no sense to me why the NEC can require a 0.9in diameter, #600mcm GEC for some systems (not this one) per 250.166(B) and then say oh wait, you installed a single ground rod? Then a #6 is all you need! in 250.166(C). But it certainly makes our lives easier. If the building GE is not a ground rod, you could still run your #6 GEC to that new ground rod, and then bond that rod to the existing electrode using whatever size jumper is required per 250.53 (which I believe would also be a #6). This lets you keep that 300' run as a #6 rather than a #4 or #2 that may be required otherwise. DKC On 2013/9/17 23:56, Gary Willett wrote: Charlie: The answer depends on whether the system (modules and micro-inverters) is grounded or ungrounded. I think you are describing a grounded system, but it's not totally clear based on your issue description. If the micro-inverter is transformer-less the conductors are not isolated between the DC-in and the AC-out. This requires the micro-inverter to have no DC-side system ground. The micro-inverter AC-side always requires an EGC. I am assuming that the PV modules are in close proximity to the micro-inverters, and the 300' home-run is for the AC outputs of the micro-inverters. Is either DC bus (PV+ or PV-) a grounded conductor, or are both busses ungrounded? If the DC-side combiners and re-combiners have OCPDs and disconnecting means for both PV+ and PV-, then your system is considered to be floating or ungrounded. If the system is ungrounded, a GEC is not required on the DC-side of the micro-inverter, and only an AC-EGC sized per NEC 690.45 is required. If the DC-side combiners and re-combiners have OCPDs and disconnecting means for only one conductor (PV+ or PV-), then your PV system is considered to be grounded. If the system is grounded, the combined DC-GEC and AC-EGC sizing requirements in NEC 690.47(C)(3) apply. The larger of the EGC (Table 250.122) and GEC [250.166(B)] sizes will be required. More specifics on the PV module Vmpp and micro-inverter you're dealing with would be helpful. Regards, Gary Willett Icarus Solar On 9/17/13 8:37 PM, Aladdin Solar wrote: We will be installing a 40KW grid-tied PV system that uses PV modules wired in parallel as per the module manufacturer -- so it's a high amperage, low voltage system on the DC side. 2 branches of about 3KW of parallel wired modules each come together onto a DC bus. The DC branch conductors are sized as 2AWG. The inverter system provided by the manufacturer consists of a number of UL1741 single phase microinverters that all are powered off of the low voltage DC bus. So there's a bunch of microinverters in parallel, combined output is single phase power. Those microinverters have a ground lug labeled GEC. You know where this is going... Assuming we are following NEC 690.47(C)(3), we'll be treating this ground as GEC and following all the GEC rules. My understanding is that because the DC conductors within the array are 2AWG (NEC 250.166(B), we will need to connect all 12 branches and 6 DC buses with continuous 2AWG and bring it all the way back 300' to where the AC GEC bond is located. We're getting a lot of pushback from the electrical sub and even some disagreement from the module manufacturer on this--no one's ever seen a grounding conductor of this size being required for this application. Please don't get too bogged down with understanding the low voltage, parallel module spec and the massive number of microinverters involved. What I'm looking for is confirmation that I am properly understanding how the NEC GEC requirements apply, especially to the GEC size. Charlie Pickard NABCEP Certified PV Installation Professional ^(TM) Aladdin Solar, LLC __ Information from ESET NOD32 Antivirus, version of virus signature database 8813 (20130917) __ The message was checked by ESET NOD32 Antivirus. http://www.eset.com ___ List sponsored by Home Power magazine List Address:RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive:http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive:
Re: [RE-wrenches] SMA WebBox - Bluetooth vs RS485
thanks for the feedback, everybody! On 2013/8/30 21:42, Jesse Dahl wrote: I have two installed so far, 0 issues. One is 5 feet from the inverter one is around 50 feet away. Lots to like! Jesse Sent from my iPhone On Aug 30, 2013, at 6:41 PM, SwingJunkie swingjun...@gmail.com wrote: Dave, We put one in early this year about 70' from the inverter. No issues so I'm a fan. Two dials to adjust, one in the inverter, one on the web box, to set the channel. No experience with the Bluetooth sensor box so chime in on results when you know more. Cheers Carl Adams SunRock Solar On Aug 30, 2013, at 3:11 PM, Dave Click davecl...@fsec.ucf.edu wrote: Have folks been having good experiences with the SMA Bluetoothed WebBox, or should I stick with the standard 485 edition? I'm guessing it'll be about a 20' max triangle between the SB1TL, WebBox, and SensorBox. Likely using a Sprint modem for the internet connection. Thanks in advance and hope everyone has a nice weekend! Dave ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] SMA WebBox - Bluetooth vs RS485
Have folks been having good experiences with the SMA Bluetoothed WebBox, or should I stick with the standard 485 edition? I'm guessing it'll be about a 20' max triangle between the SB1TL, WebBox, and SensorBox. Likely using a Sprint modem for the internet connection. Thanks in advance and hope everyone has a nice weekend! Dave ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Sunny Island question
Allan- SMA tech support confirmed with me yesterday that the 3/4/5 kW TL units are compatible with the SMA frequency shifting. On 2013/8/2 16:34, Allan Sindelar wrote: Will the Sunny Island mate up with these Sunny Boys that have the limited backup capability during an outage, as they will with standard Sunny Boys? Thank you, Allan --- Original Message Subject:Re: [RE-wrenches] SMA Secure Power Supply Date: Tue, 23 Jul 2013 23:16:23 -0600 From: Orion Thornton onsiteenerg...@gmail.com Reply-To: RE-wrenches re-wrenches@lists.re-wrenches.org To: 'RE-wrenches' re-wrenches@lists.re-wrenches.org Hi Carl and All, This spring we had the opportunity to install a 5000-TLUS inverter for a client, as a pre-release version. The inverter was commissioned on April 1st and has produced about 2.7 MWhs thus far. As mentioned, the secure power supply (SPS) requires a dedicated outlet with a switch to control its operation. For this installation we installed the SPS in the mechanical room, which is about 50 ft from where the inverter is located. We chose the mechanical room because it is centrally located within the floor plan of the home, making it easily accessible to plug in emergency type loads, i.e. cell phone chargers, laptops, lamps, etc.. It is also very close to the fridge, which we plugged in with a short extension cord and tested its operation in the stand-alone mode (which is what the inverter display when the grid is down and the SPS in activated). The inverter had no problem powering the fridge. The inverter display showed about 900 watts bypassed from the solar array to the SPS when the fridge cycled onI must say it was a very cool feeling seeing this happen. As far as the inverter itself goes, I only have a few minor complaints. Like the old SMA 1800U and 2500U, the conduit knockouts on the bottom of the inverter are at a slight angle, which means you must put a slight bend in your conduit. This is obviously a bit annoying and I can only guess it has something to do with the plug and play nature of non-U.S. installation techniques. The TLUS inverters are also lacking Bluetooth communication, unlike their HFUS counterparts. I think this is a nice feature of the HFUS inverters and wish it was integrated into the TL's. With no real difference in cost compared to traditional grid-direct inverters, I see no reason not to specify the TL, especially for someone who has a desire for limited power supply during a grid outage. They can always add a Sunny Island later on, if a more robust backup system is needed. I hope this helps. Orion Thornton Onsite Energy NABCEP Certified Solar PV Installer -Original Message- From:re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Jesse Dahl Sent: Tuesday, July 23, 2013 4:11 PM To:wire...@gmail.com; RE-wrenches Subject: Re: [RE-wrenches] SMA Secure Power Supply I know the MREA in WI has one installed on site, but not sure who installed it. Do they have a representative on the list? Jesse Sent from my iPhone On Jul 22, 2013, at 6:18 PM,wire...@gmail.com wrote: If we have another long outage here in CT and we seem to have one every year now, I don't want to have to explain to my customers why I didn't use this inverter. -- *Allan Sindelar* _Allan@positiveenergysolar.com_ mailto:al...@positiveenergysolar.com NABCEP Certified PV Installation Professional NABCEP Certified Technical Sales Professional New Mexico EE98J Journeyman Electrician Founder and Chief Technology Officer *Positive Energy, Inc.*, a Certified B Corporation^TM 3209 Richards Lane Santa Fe, New Mexico 87507 *505 424-1112 office 780-2738 cell* _www.positiveenergysolar.com_ http://www.positiveenergysolar.com/ ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Tax credit question.
The obvious disclaimers of course apply to this message... The only time a customer would find out that they were disallowed is if they are audited, right? Anyway, from the 5695 form sent out earlier, emphasis added: Qualified solar electric property costs. Qualified solar electric property costs are costs for property that uses solar energy to generate electricity for use in your home located in the United States. No costs relating to a solar panel or other property installed as a roof (or portion thereof) will fail to qualify solely because the property constitutes a structural component of the structure on which it is installed. /*The home does not have to be your main home.*/ Main home appears to be an issue only for fuel cell installations and Part II of the form (PV credit is in Part I). Home is defined as A home is where you lived in 2012 and can include a house, houseboat, mobile home, cooperative apartment, condominium, and a manufactured home that conforms to Federal Manufactured Home Construction and Safety Standards. 2012 Form 5695 It sounds like the house in Jesse's situation would qualify. A tree stand would not. 2012 Form 5695 On 2013/7/29 19:40, Larry Crutcher, Starlight Solar Power Systems wrote: We install hundreds of RV power systems, as high as $18,000 cost, and tell all of our customers about the tax credit. Many have reported back that they were allowed the tax credit. No one has ever told me it was disallowed. Some customers are full time, some only use the RV occasionally. Larry On Jul 27, 2013, at 4:41 PM, Jesse Dahl dahlso...@gmail.com mailto:dahlso...@gmail.com wrote: So, has anyone had a customer install a ITC eligible system on a second residence and claim the credit? Jesse ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Adding similar but updated modules to same inverter
I think that the 230s required positive grounding, so you can't swap out the inverter for a TL unit. These two circuits in parallel will be fine for your MPPT, you'll have essentially the same voltages but slightly higher current in your new second string. DKC On 2013/7/12 19:27, August Goers wrote: Hi Wrenches, I have a client with a small system consisting of 6 SunPower 230s and a SMA SB 3000. Anyway, he wants to add another 6 modules but the closest we can get from SunPower these days is a 245. The new six modules would go on a second string. Do you think that the slight difference in tracking voltage and current will be significant enough to justify the cost of adding or swapping the inverter? Here is the info for the modules: SunPower 230 WHT Vmpp41.0 V Impp 5.61 A Voc48.7 V Isc 5.99 A SunPower 245NE WHT Vmpp40.5 V Impp 6.05 A Voc48.8 V Isc 6.43 A I imagine that the tracker in the Sunny Boy will be a little off and perhaps the result will be that both strings will be running a few percent lower than they are capable of? Best, August *August Goers* Luminalt Energy Corporation o: 415.641.4000 m: 415.559.1525 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Tape on modules for wire management
All these manufacturers making cable clips are going to be so upset when they learn that we know about this quick, cost-effective wire management method! You could start with 110.3(B) where the module installation manual may prohibit anything adhered to the back of the module. Or 338.10(B)(4)(b) - 334.30, relating to properly supporting the cables. Or [2011] 690.4(E) qualified personnel or 110.12 neat and workmanlike manner, which is probably the most straightforward way to call someone an idiot if you want to use the NEC exclusively. DKC On 2013/7/10 21:37, jay peltz wrote: Hi all, You code wonks can help out here I had a friend ask about an install he saw that used electrical tape to attach the PV wires to the modules, yep actually taping them to the back of the module. I'm having trouble figuring out if this actually breaks any codes and if so which ones Then there is the whole ul,listing of the modules and is that approved? Thanks, Jay Peltz power ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] EGC for Enphases
Belated thanks for the replies on this, Jason et al. Sorry for my lack of a clear explanation- Jason interpreted me correctly. Apparently this Lennox unit was installed without a neutral- I'm awaiting more info from the PE. On 2013/7/5 19:25, Jason Szumlanski wrote: I think what Dave is saying is that the enphase cable neutral is connected to the EGC in the roof mounted j-box, and no neutral is run to the Lennox panel or disconnect. While the neutral should not carry line current under normal operation, Enphase calls it a neutral - look up the NEC definition of neutral. I can see an AHJ having reservations about this, whether the combined Neutral/EGC/GEC is bare or insulated. I would not waste time trying to argue this with the AHJ. I would bring three current carrying conductors plus a combined EGC/GEC to the main distribution panel, just like every other Enphase job we do. I spend a fair amount of time explaining how this solar powered air conditioner is nothing revolutionary, except for the creative marketing. Anyone out there try to team up with a HVAC company to market any A/C unit as solar powered? Jason Szumlanski Fafco Solar On Jul 5, 2013 5:14 PM, August Goers aug...@luminalt.com mailto:aug...@luminalt.com wrote: Hi Dave, I'm not sure I'm understanding your scenario clearly but I'll take a crack at it. The Enphase system should have a bare #6 GEC for each micro and can then transition to a #8 green GEC once in conduit and run all the way back to the main ground electrode system. The #6 and #8 should be irreversibly crimped together since the GEC needs to be continuous. Certainly it is not okay for the neutral in the Lennox panel to be bare unless it is somehow a main panel. You could run the DC GEC along with the other conductors and it can serve as a dual purpose GEC and equipment grounding conductor per 2011 NEC 690.47(C)(3). Best, August -Original Message- From: re-wrenches-boun...@lists.re-wrenches.org mailto:re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Dave Click Sent: Wednesday, July 03, 2013 6:26 AM To: RE-wrenches Subject: [RE-wrenches] EGC for Enphases All, I was just looking at small 4-module Andalay (Enphase 190) system tying into one of the Lennox solar-ready air conditioners. The engineer had specified the 690.47(C) GEC be run directly from the array down to the existing electrode. Running from the inverters is a 2+G wire to the Lennox panel; they are using the uninsulated ground as the circuit neutral. It seems to me that this violates 200.7 (grounded conductor marked white or grey). Also, 250.134(B) (EGC run with circuit conductors), about which the engineer states I have been studying the NEC on this and I believe that the intent is to permit the ground to be carried with the current carrying conductors, not require. Am I missing something? Thanks, Dave ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm http://www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org http://www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm http://www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org http://www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings
[RE-wrenches] EGC for Enphases
All, I was just looking at small 4-module Andalay (Enphase 190) system tying into one of the Lennox solar-ready air conditioners. The engineer had specified the 690.47(C) GEC be run directly from the array down to the existing electrode. Running from the inverters is a 2+G wire to the Lennox panel; they are using the uninsulated ground as the circuit neutral. It seems to me that this violates 200.7 (grounded conductor marked white or grey). Also, 250.134(B) (EGC run with circuit conductors), about which the engineer states I have been studying the NEC on this and I believe that the intent is to permit the ground to be carried with the current carrying conductors, not require. Am I missing something? Thanks, Dave ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] double insulated wire
690.35(D) does *not* require PV WIRE be used for the whole dc circuit. You can use either: (quoting directly from 2008) 1) Nonmetallic jacketed multiconductor cables 2) Conductors installed in raceways, or 3) Conductors listed and identified as PV WIRE installed as exposed, single conductors Similarly, I don't believe that the NEC requires red and black color coding, either, though it makes the most sense given convention. Note Brian Teitelbaum's 6/3 email about PV WIRE noting that double-insulated is a bit of a misnomer. Some PV WIRE is single-insulated. DKC On 2013/6/28 13:47, a...@aramsolar.com wrote: In ungrounded systems the PV wire requirement is to be used the whole DC circuit, so that is all the way to the inverter. 690.35 (D) is pretty clear . Because it is ungrounded the protection is the PV wire's fire rating and you don't get that with thhn/thwn. And of course Red for positive and black for negative. Most building departments have not pick up on this yet. But they will. Aram Original Message Subject: Re: [RE-wrenches] double insulated wire From: Will White william.wh...@realgoods.com mailto:william.wh...@realgoods.com Date: Fri, June 28, 2013 10:23 am To: RE-wrenches re-wrenches@lists.re-wrenches.org mailto:re-wrenches@lists.re-wrenches.org We use PV Wire which is double insulated on the roof in free air and regular THHN/TNWN for the run from the junction box back to the inverter (using no white or gray wires of course). Thanks, Will Will White Regional Field Operations Manager -- New England Real Goods Solar 64 Main St. Montpelier, VT 05602 Tel: (802) 223-7804 Cell: (802) 234-3167 www.realgoodssolar.com http://www.realgoodssolar.com/ *From:*re-wrenches-boun...@lists.re-wrenches.org mailto:re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *Marco Mangelsdorf *Sent:* Friday, June 28, 2013 1:10 PM *To:* 'RE-wrenches' *Subject:* [RE-wrenches] double insulated wire I'm kinda confused. With more transformerless inverters on the market (e.g., SMA and Power-One), it's not clear to me if double insulated wiring needs to be used all the way from each series string to their respective inverter. We've been installing the P1 3-6 kW TL inverters and there's no apparent mention of needing to use such conductors, yet I remember needing to do so when I installed a number of the 8, 9 and 10 kW SMA TL inverters. Thanks, marco ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm http://www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org http://www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Full sized neutral - 240 V inverter
Unfortunately, the benefits are somewhat limited since you still have to size the neutral at the same size as your EGC, and you have to upsize your EGC thanks to your voltage drop. So now instead of a #6 neutral, you're running them as 8s? Hey, every bit helps... On 2013/6/20 16:18, Drake wrote: Hi Wallace, For services, at least, in the 2011 NEC, the neutral is still sized per Table 250.66 (250.24 (C) (1). I took Allan's suggestion and called Power One tech support back. The neutral carries no current; it is strictly for sensing. Drake At 02:23 PM 6/20/2013, you wrote: Drake, Full sized neutrals are now required due to harmonics at least. The cost over your quote for neutral is fixed. What is the cost for unknown consequences if you disregard manufacturers specs? Wallace Stahle Future Electric Energy Co P O Box 236 Willits, CA 95490 fut...@pacific.net mailto:fut...@pacific.net CA Lic.# C10-762093 707-459-0474 On Jun 19, 2013, at 3:26 PM, Drake wrote: That was my first call. They said use a full size neutral. I'm not satisfied with that answer. The combined experience and knowledge on this list far exceeds that of any tech support person. At 04:27 PM 6/19/2013, you wrote: Drake, Why not discuss this with Power One tech support? Allan *Allan Sindelar* _al...@positiveenergysolar.com mailto:al...@positiveenergysolar.com_ NABCEP Certified PV Installation Professional NABCEP Certified Technical Sales Professional New Mexico EE98J Journeyman Electrician Founder and Chief Technology Officer *Positive Energy, Inc.*, a Certified B Corporation^TM 3209 Richards Lane Santa Fe, New Mexico 87507 *505 424-1112 office 780-2738 cell* _www.positiveenergysolar.com http://www.positiveenergysolar.com/ _ On 6/19/2013 1:55 PM, Drake wrote: A very common cable for 100 A service conductors has 2 - #2 AL wires and 1 - #4 AL for the neutral; 200 A will have 2 - 4/0 AL wires and 1 - 2/0 for the neutral. If I run # 2 to limit the VD on the run to the panel and reduce the neutral to #4, #12 copper phase and neutral will still connect to the inverters. This would be code for a feeder to a separate structure. Does the Power One inverter actually have a major imbalance resulting in substantial neutral currents? If so, it is really a 120 V inverter for VD calculations. 03:37 PM 6/19/2013, you wrote: Content-Type: multipart/related; boundary==_NextPart_000_00A6_01CE6CE9.D20EFB20 Content-Language: en-us Doug, 705.95(B) allows you down size your neutral if it is used solely for instrumentation and it must be sized equal to or larger than the EGC but this is not the case. If Power One says a full size neutral is needed than that means that it is not just a voltage sensing conductor used for instrumentation and that it does carry current. I don’t believe there are any exceptions in code for downsizing your neutral in regards to upsizing the conductors to account for voltage drop but I could be wrong. -- John Stimac | Corvallis, OR Renewable Energy Associates LLC 541-754-2001 Office/Fax j...@renewableassociates.com mailto:j...@renewableassociates.com www.renewableassociates.com http://www.renewableassociates.com/ 2221ada.jpg *From:* re-wrenches-boun...@lists.re-wrenches.org mailto:re-wrenches-boun...@lists.re-wrenches.org [ mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *Drake *Sent:* Wednesday, June 19, 2013 6:42 *To:* re-wrenches@lists.re-wrenches.org mailto:re-wrenches@lists.re-wrenches.org *Subject:* [RE-wrenches] Full sized neutral - 240 V inverter Hello Wrenches, Power One tech support said that full sized neutrals had to be run to a pair of 240 V, PVI 3.6 inverters. We have a 180 foot underground run to the service panel. Why do we need to run a full sized neutral all the way back to the panel? The wiring to the panel is oversized for voltage drop. The code allows for reduction of neutral size where neutral imbalance is less than the current of a phase, which is usually the case. Why does a neutral need to be installed that is the size of the phase wiring where the imbalance should be negligible? Or is there a lot of neutral current for some reason? Am I missing something? Thanks Drake Drake Chamberlin /Athens Electric LLC OH License 44810 CO License 3773 NABCEP Certified Solar PV Installer 740-448-7328 /http://athens-electric.com/ ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm http://www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org http://www.members.re-wrenches.org/ ___ List sponsored by Home Power magazine
Re: [RE-wrenches] Solar Edge v. micro inverters
As a quick clarification- SolarEdge requires PV WIRE per 690.35. Regular USE-2 doesn't work for these systems. On 2013/6/15 7:25, SwingJunkie wrote: Marco, We installed our first Enphase system in December 2009, and our last in December 2011, when their high failure rate became a problem. (Currently 10%+ for us). We were only installing the Enphase units on sites with shading issues, as a means to mitigate conditions. After moving away from Enphase, we selected SolarEdge as the solution of choice for those sites. The installation labor is comparable to the Enphase solution, separate device under each module. One clear advantage is that there are no custom trunk cables required, just the standard USE-2 cable and connectors. Our field experience has been better than expected production, and 1.4% failure rate. In December we installed a SolarEdge system just down the street from a site where we had previously installed an SMA string inverter on an unshaded site. The SolarEdge system has some shading. Both arrays have roughly the same orientation and pitch. To date the SolarEdge system with shading continues to out produce the unshaded SMA system by 5-8% kWh/kWp. I agree with your intuition on fewer components making a better solution and IF there is a reliable solution that accomplishes this that would be preferred. I just priced out the Mage AC module (SolarBridge technology) side by side with the Mage - SolarEdge combination and the later is less expensive equipment wise but I think that advantage would be erased by labor savings on the install. All that said I'm still a fan of the old fashioned string inverter solution unless the site shading conditions and or array geometry require an alternate solution. Cheers Carl Adams SunRock Solar On Jun 14, 2013, at 9:15 PM, Marco Mangelsdorf ma...@pvthawaii.com mailto:ma...@pvthawaii.com wrote: I've been educating myself on the Solar Edge product v. using micro inverters. If you click on the link below, you can read the pitch that they make for using their product over micros. Any opinions out there on how convincing their strategy is? As well as any experience in the field with the product? Intuitively, it seems to me that if you can accomplish what you need to accomplish (DC power from the PV mod to usable AC power) with fewer parts (as in a micro inverter instead of a DC-DC converter and a separate inverter), then that approach makes more sense. http://www.solaredge.us/groups/us/technology/microinverters thanks, marco ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm http://www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org http://www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] 200 Amp Main Equip for 60A Solar
Jeff, This has been sent out on the list a few times but I don't remember anyone sharing their personal experiences with it: http://solarprofessional.com/articles/products-equipment/product-launches/milbank-offers-load-tap-connector 200+ 60 for a meter main is trickier. The $1100 (list) Schneider RC2M200S lets you do a 200A main and a 50A PV breaker (interconnecting on line side of the 200A), which may be close enough for you depending on your system details (10kWac @ 240V - 52.1A breaker). DKC On 2013/6/12 21:09, Jeff Clearwater wrote: Hey Wrenchies, Anybody know of a 200 Meter base with lugs rated for dual wire so we can do a 60 Amp Supply side solar feed on a 200 Amp service? Or does anyone know the right equip to get to ensure we can install 2 dual lug taps on both single lugs? (a meter base with enough room for the T lugs?) Or better yet any integrated 200 Amp Service / Meter equipment that has an accessible spot to tap 60 Amps for a Disconnect on the meter side of the Main? I have 2 SB 2500Us existing and want to add a single SB 5000TLUS - I show rated output to be 46 Amps total and hence a 60 Amp needed. Advice my esteemed colleagues? Thanks, Jeff -- Jeff Clearwater Village Power Design Renewable Energy Design Installation Ecovillage Design Consultant www.villagepower.com 413-559-9763 ~~ ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] 3-phase PV Inverters for 600 VAC Mfg Plant
Actually, one is the manufacturer closest to you, Paul- the Solectria SGI 225-500kW class does a 600VAC output. On 2013/5/15 14:03, Paul Lyons wrote: Stump the RE-Wrenches: You know the NPR radio show, Car Talk, when they play Stump the Chumps? I visited a manufacturing plant last week that has a 13.8 kV primary service that is stepped down to 600 VAC secondary by an indoor 1500 A transformer and distributed around the plant to the large pieces of equipment. There is a small transformer for 240/120 single-phase devices in the relatively small office area. Do any of you know where I can find a UL-listed 3-phase inverter in the 300 kW range that can be interconnected to the 600 VAC buss? There is a spare 600 A breaker. Feel free to contact me off the list. Thank you. Paul Lyons, P.E. Zapotec Energy Inc. 675 Massachusetts Ave Cambridge, MA 02139-3309 Tel: 617-547-5900 ext.201 Email: ly...@zapotecenergy.com mailto:ly...@zapotecenergy.com ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] PV-direct electric water heating
At SPI last year there was at least one company offering this, and there's another company from Tallahassee also looking into it: www.usa-eds.com I'm not an expert by any means but I think that even 120F doesn't kill legionella-- you need to get to 140F. And even if you do 140F, I imagine you could still have it in the bottom of the tank (if it's electric). A few years ago, a Solar Decathlon team used some kind of ionization to combat it, I believe using something intended for hospitals. DKC On 2013/5/14 8:39, Steven Lawrence wrote: Luke, Most tankless hot water heaters can't accept pre-heated water. Some of them can, but even still these have a minimum heat input into the water. You may run into a situation where you have 105F water into the tankless and the thing won't fire up due to safety reasons (can't put out 130F or something similar like that). And the issue with 105F is you start exposing yourself to the potential of getting Legionnaires' disease. -Steven Hi Wrenches, Now that the cost of modules has come down so much, has anyone out there experimented with solar electric water heating? As in: direct connecting a short series string of PV modules to a tank -style electric water heater with an element of an appropriate voltage and wattage rating?? A off-grid customer of mine who is also an electrical engineer has a situation that seems ideal for trying this idea out: he has a gas-fired tankless water heater and a water source that is very cold year-round. The idea is to take a 30 or 40 gal electric tank heater, switch out one of the the 240V elements to something like a 96VDC, 1000W element (difficult to find, but available), and direct connect 3 or 4 60-cell modules in series (with a disconnect and high-limit control of course). The tank would then serve to preheat the cold feed to the tankless heater. We think we can get a decent daily temperature rise with this setup. Probably not enough to heat the tank to a normal DHW temperature, but certainly enough to offset a good deal of propane consumption, and all for what I predict will be considerably less cost than a small solar thermal system. Has anyone tried this? I'd appreciate any insights or opinions. Thanks -Luke Christy ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Dual Channel Inverters; Hosed By Fronius
Another option would be to compensate the customer for lost production until you're out there to replace a second inverter. You can credit this against Jason's diagnostic fee idea and/or the $150/unit reimbursement from Enphase. Each unit down is about $30-60/year depending on location. Could help those of you working on tough multi-row installations on steep roofs, especially with larger systems and more units to fail. Downsides: some customers will insist on individual replacements as needed-- the let's just wait for the second inevitable domino to fall approach is a tricky sell... weighing $150/unit now vs unknown future Enphase policy may not be compatible with your warranty policy On 2013/5/9 11:51, Jason Szumlanski wrote: Why would you rip apart an array? We only remove one module in almost every case, replace the WEEBs, replace the inverter, and we're done. If there are more than two rows of modules, you might need to remove an additional module or two, but that takes almost no time. Our steepest roofs here are typically 6:12, with many shallower, so you folks up north probably find it much more difficult, and I understand that. Also, there isn't any rule that you can't charge the customer a diagnostic fee. We don't because the reimbursement does adequately compensate us, but if your costs are legitimately higher, recover them from the consumer like most appliance warranty service companies do. *Jason Szumlanski*// /Fafco Solar / On Thu, May 9, 2013 at 10:54 AM, Troy Harvey tahar...@heliocentric.org mailto:tahar...@heliocentric.org wrote: but it also takes MUCH less time in most cases and can be done much more easily by one service technician. It's not a money maker, but it covers cost in our neck of the woods. How is that possible? I get a lousy $150 dollars from enphase to rip apart half of a array just to get at the micro inverter. Then I have to put the array back together. Its an all day activity for two people for 1 inverter. And then I have to do it on the same array the next year again. With a string inverter the swap is simple. thanks, Troy Harvey - Principal Engineer Heliocentric 801-453-9434 tel:801-453-9434 tahar...@heliocentric.org mailto:tahar...@heliocentric.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] UL warns of counterfeit UL Mark on photovoltaic panels
Wrenches will especially enjoy the IMP and ISC values, pictured in the final image of the UL notice. On 2013/4/16 13:29, Jason Szumlanski wrote: Ray Johnson in Florida has done an excellent job documenting this fiasco on his blow in the article below and several other articles. http://www.renewableenergyworld.com/rea/blog/post/2013/04/solar-contractors-installers-beware-of-the-panel-warranty-bait-switch W e lost several jobs to this company in the past due to unsustainable low competitive prices. I was sounding the alarm on this a couple of years ago - I thought they were dumping product on the market to establish their contracting/sales arm. It seems they were up to much more than that. *Jason Szumlanski* /Fafco Solar/ On Tue, Apr 16, 2013 at 11:16 AM, Nik Ponzio npon...@buildingenergyus.com mailto:npon...@buildingenergyus.com wrote: http://www.ul.com/global/eng/pages/newsroom/publicnotices/detail/index.jsp?cpath=/global/eng/pages/newsroom/publicnotices/detail/data/ul-warns-of-counterfeit-ul-mark-on-photovoltaic_2013041507.xml UL warns of counterfeit UL Mark on photovoltaic panels (Release 13PN-20) *NORTHBROOK, IL - April 15, 2013 -* The following is a notification from UL to Authorities Having Jurisdiction, distributors, installers and users that the photovoltaic panels identified below bear counterfeit UL Marks for the United States and Canada . The photovoltaic (solar) panels have not been evaluated by UL to the appropriate Standards for Safety and it is unknown if these photovoltaic panels comply with UL's safety requirements for the United States or Canada. *Name of Product:* ASP - Advanced Solar Photonics (also known as Bluechip Energy) Models AP-240PK, AP-245MK and ASP-390M Note that ASP is a tradename for the parent company Bluechip Energy LLC *Identification: */On the product:/ The products bear a counterfeit UL Mark and one of the markings shown below: Note that the labels include additional electrical rating information, but the values may differ from that shown in the photographs below. *Photos of Product: * *Photo of typical installation* ** *Counterfeit nameplate from Model AP-240PK* The nameplate label for Model AP-245MK is identical to the label above except for Model number and electrical ratings. ** *Counterfeit nameplate from Model ASP-390M* ** *Sold at: *Known to be sold by SunWorks Solar and may be sold by other distributors ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Teck 90 cable
I don't believe this would work; official metal-clad cable would, but not armored cable. Metal-clad only works under the 2011 NEC, and only then when it meets 250.118(10). On 2013/4/11 19:24, Hilton Dier III wrote: I asked this one last year and got a few That's interesting responses, but nobody actually came up with an answer. Perhaps it was too obvious. I have been looking at Teck 90 waterproof metallic armored cable as a possibility for DC wire runs. This is the stuff: http://www.onestopbuy.com/omni-wire-cable/T30804-40643.asp It seems to be roughly the cost of wire and conduit and a lot easier to run. It looks versatile: Suitable for use in ventilated, non-ventilated and ladder cable trays, direct earth burial or raceways, and for exposed or concealed wiring in wet, damp or dry locations. Suitable for use in wet or dry locations when installed in accordance with the NEC. The question is, would this stuff be acceptable code-wise for metallic-contained interior DC wire runs per 690.31 (E)? You'd think so, but I'd want to be sure before buying a reel of this stuff. Thanks, wrenches! Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] SINGLE PHASE OUTBACK SYSTEM ON 3 PHASE SERVICE
What problems is the system having? Regarding your proposed 3P wiring solution, I don't know whether this has been fixed recently, but Outbacks in 3P historically haven't monitored the angle between phases. Under grid-connected operation it's not a problem, but after they lose the grid connection, you'd be relying on each inverter independently and consistently putting out exactly 216,000.0 cycles of AC. This is only a problem with 208V 3P or 1P loads on your protected load panel. Since you don't have those currently, you'd be OK as long as you upsize the neutral and add a placard stating that no 208V loads should be added. DKC On 2013/3/28 11:23, Bill Turberville wrote: I know I saw a thread on this but I cannot find it in the archive. I have inherited a customer that has a four inverter Outback system, 240V 1 Phase, on a 208Y120V 3 Phase 4 Wire system, that constantly has problems. A 208V to 240V 1 phase transformer was installed feeding the input, but the system still struggles. Will this system ever work correctly as is, or does it need to be rewired for 3 phase and use the third inverter as a spare. This would include a lot of work rewiring the output panel. Any ideas? W.C. (Bill) Turberville P.E. President ECE Solar Electrical Contracting Enterprises LLC 3080 Stage Post Road Suite 107 Bartlett, TN 38133 901-348-9230 ext 101 phone 901-348-2192 fax 901-289-6346 cell billt...@ece-llc.com mailto:billt...@ece-llc.com ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] P1 micro performance
Marco, I still challenge those who believe that “some clipping is good” to make their case. Well, the way you've phrased it, you've made my job pretty easy-- though it seems to me that several folks have already done this for you. Some power limiting at some point over the 25-year life of a system is definitely a good thing. A 25-year life corresponds to about 110,000 hours of daylight. Let's say that you can expect one total hour of those 110,000 in which a Montana system sees 1600 W/m2 (high slope, snow reflection, edge-of-cloud) while simultaneously experiencing a record low temperature and 50 mph winds. Would you put a 9kW inverter on your 5kW array to avoid any power limiting ever? Of course not-- you're substantially increasing system cost for a $0.15 gain. It comes down to figuring out probabilities and doing some complicated and annoying math to figure out the best size for an inverter. Or more realistically, attempting to get high-sample-rate weather data to simulate array performance at your target location. When you oversize an inverter, your system will be operating at a lower efficiency, on average. It increases the cost to the customer not just from the base cost of the larger unit, but also the larger output conductor and raceway sizes, the output disconnect, the interconnection breakers/fuses... and maybe even upsized panelboards that didn't actually need to be upgraded had you correctly sized the inverters. So you have to figure out whether the additional production is worth the increased cost of installation. Oversizing an inverter may extend its life but I don't know that we'll ever have those numbers from manufacturers to better quantify that impact. More current causes more heat, which is bad, but increasing an inverter size to the next higher power rating available doesn't guarantee that the larger inverter will be more reliable. So that's a general response. As for your Power-One 250 vs Enphase 224 conundrum, if all else is equal but the power rating, then I'd probably join you in choosing the Power-One. But as you know, there are other factors to take into account-- [perceived] reliability, BOS cost (e.g. more Enphase units fitting on a 20A breaker may save you a circuit), DAS usefulness, resistance to corrosion, and the fact that Enphase operates at a higher conversion efficiency in the lower half of its operating range (where it spends most of its operating time). I am not saying that Enphase is better than Power-One in anything but low-range efficiency-- I don't know one way or the other. Efficiency Curves: http://gosolarcalifornia.com/equipment/inverter_tests/summaries/Enphase%20M215%20IG-240V.pdf http://gosolarcalifornia.com/equipment/inverter_tests/summaries/Power-One%20MICRO-0.25-I-OUTD-US-240.pdf After all this discussion, it's pretty funny that the peak conversion efficiency of the 250W Power-One micro occurs at... a 250W output. So even though the marketing guys tell you you should only plug in a 265W module, the engineers are clearly asking you to turn it up to 11. Do you, Mr./Mrs./Ms. Homeowner, want a PV system that produces as much solar kWhs for your investment as possible? isn't the right question to ask. Try, Do you, Mr./Mrs./Ms. Homeowner, want a PV system that produces the best value for your investment? Then show your super impressive calculations, based on your years of experience, that your recommended inverter is the best fit for them. Allowing for maximum kWh harvesting, within reason, is the best design strategy. Dave 5.376kWdc on a 5.000kWac, and loving it On 2013/3/23 19:31, Marco Mangelsdorf wrote: From Dan at Exeltech: Trying to explain in depth the how and why slightly larger PV is of benefit to a customer is like trying to explain photovoltaic equipment to the general public. I still challenge those who believe that “some clipping is good” to make their case. And as far as the general buying public, I’m find that people do in fact understand when you ask them the following questions: Do you, Mr./Mrs./Ms. Homeowner, want a PV system that produces as much solar kWhs for your investment as possible? Usual response: absolutely. If I give you the choice of PV system using a 250-watt module paired with a COMPARABLY priced 250-watt micro inverter OR that same 250-watt module with a max output ~ 224-watt micro inverter that will never under any circumstances allow that 250-watt module to put out its max rated power output, which option do you think they’ll choose? They get that. It doesn’t take someone with an engineering degree or 10-40 years in the field to get that simple premise. For what it’s worth, being here in the tropics in the Hawaiian islands we don’t get those bright and sunny and cold late fall/winter/early spring days that will allow for an array to put out its STC-rated power. But seeing regular times during the day—any time of year—where the irradiance is more than 1,000
Re: [RE-wrenches] backup without batteries
http://www.smainverted.com/2013/02/21/groundbreaking-new-feature-on-sunny-boy-tl-us-emergency-power-when-the-grid-fails/ On 2013/3/25 11:56, Nik Ponzio wrote: Forgive my senility. I recently read somewhere about development of grid-tie inverters without batteries that offer emergency power via a single 120V receptacle during grid outage (and sun.) Anyone seen anything on these? The brands mentioned were SMA Mitsubishi. Thanks in advance. -- Nicholas Ponzio Building Energy 1570 South Brownell Road Williston, VT 05495 802-859-3384 ext.15 (office) 802-658-3982 (fax) 802-318-4783 (cell) http://www.BuildingEnergyVT.com ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Conductor Sizing for Supply Side Connection
As a note, supply side connections have an extra complication with battery backup systems. With a regular GT inverter you're just pushing current into that interconnection point and you can work out easily that you won't have any overcurrent issues unless you made a big mistake and your inverter output exceeds the rating of your service conductors. However, with a battery system you're also potentially pulling current from that point. Before the battery inverter is installed your main breaker protects your service conductors, but if the inverter is pulling in 60A and the main breaker is also operating near its capacity, you could have 240A running over 200A service conductors with no breakers tripping. You would overwhelm the capacity of the service [230.23(A)] and no breakers would trip. You could fix this by replacing your service conductors back to the transformer (I'm just saying that it's an option) or downsizing the main breaker, and at that point you're probably better off just making it a load side connection. I'd go load side and argue with the AHJ to use the 2011 update mentioned earlier. Dave On 2013/2/28 9:55, Garrison Riegel wrote: Allen, The benefit I see would be to allow for a code compliant load side connection on a 200A panel with a 200A MB, where the AHJ is on the 2008 NEC or older and will not listen to your good logic. I don't think this would always be the best option, but if backup loads and inverter output were less than 32A then a 40A OCPD in the main panel should be fine? Since it sounds like the 60A breaker in the main panel is not a safety issue, but a design consideration, I suppose I would just prefer flexibility when possible. That said, this AHJ is on the 2008, and the loads will be less than 30A, but based on this conversation I plan to go with a 60A and try to convince the AHJ that it will be code compliant in their future! Thanks, Garrison *From:*re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *Allan Sindelar *Sent:* Thursday, February 28, 2013 8:14 AM *To:* RE-wrenches *Subject:* Re: [RE-wrenches] Conductor Sizing for Supply Side Connection Garrison, I don't know why it's not listed as 60A max, but my own internal logic would ask why it should be. The only benefit I could see for using smaller than a 60A breaker would be to allow use of #8 conductors (allowed with a 40A or 50A breaker) instead of the #6 necessary with a 60A breaker. And of course, you could use a 40A breaker with #6 conductors, so theoretically it would be fine. I just fail to see any benefit to doing so. Allan *Allan Sindelar* al...@positiveenergysolar.com mailto:al...@positiveenergysolar.com NABCEP Certified Photovoltaic Installer NABCEP Certified Technical Sales Professional New Mexico EE98J Journeyman Electrician Founder and Chief Technology Officer *Positive Energy, Inc.* 3209 Richards Lane (note new address) Santa Fe, New Mexico 87507 *505 424-1112* www.positiveenergysolar.com http://www.positiveenergysolar.com/ On 2/28/2013 6:27 AM, Garrison Riegel wrote: Thanks Allen for clarifying why a 60A is required. I was wondering. The spec does list a surge current of 9000W so I thought that may be the rationale, but even that would only require a 50A, and since this surge occurs during 'stand-alone mode' it didn't seem to apply to the OCPD at the main panel. Your explanation makes more sense, but I wonder why then they don't list the AC input breaker size as 60A /max/. If you have few backup loads, and are not on the 2011 NEC, a 40A could theoretically be fine? Thanks all for your thoughts, much appreciated. Garrison *From:*re-wrenches-boun...@lists.re-wrenches.org mailto:re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *Allan Sindelar *Sent:* Wednesday, February 27, 2013 6:08 PM *To:* RE-wrenches *Subject:* Re: [RE-wrenches] Conductor Sizing for Supply Side Connection August, The 60A breaker is intended to allow grid power to pass through to the loads in excess of the inverter's stand-alone output. The point of 705.12 (moved in the 2011 NEC from 690.64 (B)(2)) is to differentiate between load pass-through current and sell current. The amount of current fed into the grid is (4500/230 =) 19.56A, while the amount that can be taken from the grid and passed through to the load is much greater. If you were limited to a 40A breaker in order to maintain 120% of a 200A main bus, you'd be prone to nuisance trips under large cumulative loads. Allan *Allan Sindelar* al...@positiveenergysolar.com mailto:al...@positiveenergysolar.com NABCEP Certified Photovoltaic Installer NABCEP Certified Technical Sales Professional New Mexico EE98J Journeyman Electrician Founder and Chief Technology Officer
Re: [RE-wrenches] CIS mods
This could just be due to the better temperature coefficient, or maybe they do slightly better than cSi at lower irradiance levels? Solar Frontier CIS: -0.31%/degC SolarWorld poly: -0.45%/degC I don't know enough about CIS to comment on the light soaking. On 2013/2/18 8:36, Marco Mangelsdorf wrote: Aloha, Solar Frontier in Japan, the maker of copper-indium-selenium (CIS) mods, claims that their product produces more kWhs per kW installed than crystalline silicon. http://www.solar-frontier.com/eng/cis/index.html If you go to the Softbank Field Results on the right tabs area you can download a 4-page PDF report. I’m wondering if this is a hot-out-of-the-box phenomenon similar to some other non-cSi products and that after X months in the field the output stabilizes at a lower level. Anyone have any idea or experience with this? Thanks, marco ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Enphase AC Frequency out of Range
For these installations, do you guys have more information on the utilities' protocols that are causing problems with these inverters? On 2013/2/5 12:51, penobscotso...@midmaine.com wrote: Will do. Enphase had originally projected the beginning of February for the release of the fix. It is now projected for the end of March. I am hoping it will be a done deal before this next season starts here in Maine. It might be good incentive to try Power One, Exeltech or other inverters. In all honesty, my interpretation is that the Enphase inverters are very sensitive and respond quickly to these pings. I believe the software fix will allow the inverters to ignore micro-events of less than 1/100th of a second or so (the length of the ping. I will keep the list in the loop! Daryl We see the same issue here in WI. Funny that you say 64 minutes, as some of the M215s show the error for 64 minutes for us routinely. Could that just be some designated error reporting length? Daryl, thanks for the Enphase update. Keep us updated if you can on the software fix. Ryan Harkins NABCEP Certified Solar PV Installer / Project Manager Synergy Renewable Systems, LLC PO Box 58 Stoughton, WI 53589 PH: 608-712-7862 ryan.hark...@energycraft.com www.energycraft.com On Feb 5, 2013, at 11:10 AM, Dave Palumbo wrote: Thanks Daryl. Does your system also sometimes stay off for longer periods sometimes? My clients system can stay off for up to 64 minutes. Dave -Original Message- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of penobscotso...@midmaine.com Sent: Tuesday, February 05, 2013 12:01 PM To: RE-wrenches Subject: Re: [RE-wrenches] Enphase AC Frequency out of Range Dave, We have been having the same problem with an Enphase system in Maine. I have been dealing directly with the third tier engineers at Enphase and they are working on a software fix for this. Theevent itself is only a fraction of a second but IEEE requirements are that the inverter shut down for five minutes. I only found out about this problem when it started for this customer. It sems that Enphase has already addressed the problem with a software fix for the M-190's. The M-215 fix should come, according to Enphase, by the end of March. It will be automatically downloaded through the Enlighten router. It's a known issue with Smart Meters with Enphase, but should be reconciled soon. Daryl DeJoy NABCEP Certified PV installer Penobscot Solar Design www.penobscotsolar.com Wrenchsters, I have an Enphase 7.5kW system on a residence with utility Smart Metering, both the PV Production Meter as well as the utility billing meter being read every hour. This system has experienced many AC Frequency Out Of Range events since the system was installed. Below is copied the Enphase Event message. This particular event was for 5 minutes. Most of the events (all events are AC Frequency Out Of Range) last 5 to 10 minutes but occasionally they have lasted from 45 minutes to 64 minutes. My question is: Could the use of the smart metering increase the likely hood that AC Frequency events happen? Or is this just a coincidence and that we are dealing with fluctuating utility power AC Frequency issues? Started on: Mon February 04, 2013 12:49 PM EST Cleared on: Mon February 04, 2013 12:54 PM EST Recommended action This condition should correct itself. No action is required. Details The microinverter reports that the frequency coming from the utility is either too low or too high as specified by applicable regional standards. AC frequency is the frequency at which voltage varies on the utility grid. Frequency Out of Range events are usually transient and self-correcting by the utility. When the microinverter detects an out of frequency condition, it must remain offline until the utility has been within acceptable limits continuously for a short period of time (seconds to minutes, varies by region). If during that time the utility again exceeds or falls short of acceptable limits, the five-minute timer must restart and the microinverter may not begin producing power for an additional short period following the last out-of-bounds condition. Best, Dave David Palumbo Independent Power LLC 462 Solar Way Drive Hyde Park, VT 05655 www.independentpowerllc.com Vermont Solar Partner 25 Years Experience, (802) 888-7194 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address:
Re: [RE-wrenches] Hawaii Frequency Settings
That's correct, it's a 57.0 - 60.5 Hz operating window. http://www.heco.com/portal/site/heco/menuitem.508576f78baa14340b4c0610c510b1ca/?vgnextoid=12a290a2decab110VgnVCM105c011bacRCRDcpsextcurrchannel=1#bk6 According to that website, the requirement only applied to systems interconnected after 2011/12/23 (maybe someone was trying to be poetic by having this change take effect at the winter solstice) so this would only be encouraged for legacy systems. I'll leave it to a HI-based installer to comment on how easy it is to actually upgrade inverters to this wider window. I'd guess you have to order directly from the inverter manufacturer to get these settings pre-configured. When the grid has excess loads and not enough generation, the frequency drops. Similarly, excess generation causes the frequency to increase. By opening the inverter window on the low end, this keeps all that PV generation online when the grid needs as much power as it can summon. The inverter window remains a maximum of 60.5Hz since the utility can just dial back their own generation-- excess generation is much easier to solve than excess load. In the continental US, grid operators can usually rely on nearby resources (natural gas-powered peaker plants, for example) to help provide additional power when it's needed in an area. This makes frequency problems pretty rare for us. Unfortunately for Hawaii, the nearest backup generator is a few thousand miles away. Puerto Rico has similar requirements for the same reasons. I believe that next week the IEEE 1547 committee will finalize what exactly these windows will be in the new edition. Dave On 2013/2/4 18:44, Mark Frye wrote: Folks, I was told that because the HI grid has poor frequency control, grid-tied inverters have to have their low frequency limit set to 57 Hz so they can ride out the worst low frequency events. I find it hard to believe that this has been done for every single inverter installed in HI. But, what do I know. Can anyone shed some light on this? Thanks, Mark Frye Berkeley Solar Electric Systems ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Are PV Systems Mechanical Equipment
Jason, There's a 2009 Broward County interpretation that you should be able to use for some leverage: See Page 23 (or search for solar)- http://www.broward.org/CodeAppeals/Documents/FIWebDoc.pdf Obviously, it's difficult to move an 8000 pound chiller off a roof to reroof beneath it, whereas PV would be easy but tedious. Clearly a chiller should be elevated. I'd agree that PV should only be elevated if they're requiring the same clearances under a lightning protection system. Dave On 2013/2/2 10:31, Jason Szumlanski wrote: That is my usual common sense argument - no regular maintenance. There is no more maintenance than a lightning protection system, attic fan (with moving parts) or other roof mounted apparatus. It would be nice to have a specific exclusion listed in the code. *Jason Szumlanski*// /Fafco Solar / On Fri, Feb 1, 2013 at 3:45 PM, Steven Lawrence lawrenceste...@gmail.com mailto:lawrenceste...@gmail.com wrote: The state of NJ has rules that PV modules do not require regular maintenance thus the clearance rules and access do not apply. It's somewhere in the construction code communicator of 2008-2010. It maybe not exactly what you're looking for, but maybe it'll help. Date: Thu, 31 Jan 2013 15:44:31 -0500 From: Jason Szumlanski ja...@fafcosolar.com mailto:ja...@fafcosolar.com To: RE-wrenches re-wrenches@lists.re-wrenches.org mailto:re-wrenches@lists.re-wrenches.org Subject: [RE-wrenches] Are PV Systems Mechanical Equipment? Message-ID: CAJJtG3qj7sVpjD-=w1ynbn7dckd9wb9zlo673w+dd6x7af7...@mail.gmail.com mailto:w1ynbn7dckd9wb9zlo673w%2bdd6x7af74%...@mail.gmail.com Content-Type: text/plain; charset=iso-8859-1 The Florida Building Code definitions of equipment and appliances in the Mechanical Code do not include solar arrays, yet some building officials insist on applying provisions of the mechanical code. Specifically, we get quite a few comments about mounting height above the roof and permanent access ladders and platforms. What is your experience in your state, and do you consider solar arrays to be mechanical equipment. (If you have any ammo specific to FBC 2010 that I can use, I'd be happy to get your thoughts off-list). *Jason Szumlanski** * *Fafco Solar* ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Commercial design predicament
Daryl, I don't think there's a practical way to make this work either. If you were adding a 500kW load to that site, the utility would gladly bring out a three-phase transmission line with an appropriate transformer. Unfortunately, for a solar farm, the utility probably wouldn't be willing to do that for free and would require three-phase service-- even though it's technically possible with a big batch of 10kW 1P inverters. Unfortunately, running the line that mile out to you could be a few hundred thousand dollars. It's worth checking with the utility, but I'd guess you'd have to pay for the extra mile of 3P distribution line. Dave On Fri, Dec 14, 2012 at 10:12 AM, penobscotso...@midmaine.com wrote: Hello fellow wrenches, I am hoping someone here has come across this before and might have a suggestion or two for us. I have a client who has a large piece of land and the financing for a 500 kw solar farm in Maine. The predicament I am in is that the closest three phase primary is more than a mile away. The existing single phase, 7200 volt lines to the three phase portion of the grid could easily handle the -80 amps extra load coming onto it from the central inverters, it is just that I cannot find, anywhere, a practical way to make this work, that is, converting the three phase output of the central inverter(s)(480v) to the requirement for the grid (7200 v single phase). Any ideas?? Suggestions? Thank you, Daryl DeJoy NABCEP Certified PV installer Penobscot Solar Design ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] off grid PV connected to generator
Well summarized. I think your mileage would vary based on the anti-islanding algorithm used in the inverter and the generator's ability to regulate frequency. So while it may work in that an inverter syncs to a small generator's output, it's very unlikely that reverse current backfed into the generator was considered during the generator design. Feeding 3kW of PV back into a generator that had 6kW of load isn't going to drop your fuel consumption by 50%, either. Given that the best case scenario is marginal fuel savings and the worst-case scenario is a fried regulator board taking your generator offline when you need it most, I'd keep them separated. DKC On 2012/12/13 10:18, August Goers wrote: Hi All -- Thanks for the feedback. Yea, we've always used Sunny Islands with batteries for anything that needs to run off grid. This was more of just a theoretical question. From what I heard, it sounds like the excess current from the PV might damage the generator (or I suppose anything running in the house) and this will result in higher voltage. Best case, the inverter will cycle on and off. V = I*R. Worst case something blows up. Thanks, August *From:*re-wrenches-boun...@lists.re-wrenches.org mailto:re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *Greg Seelhorst *Sent:* Wednesday, December 12, 2012 8:18 PM *To:* 'RE-wrenches' *Subject:* Re: [RE-wrenches] off grid PV connected to generator August – I’ve seen this scenario and it is not pretty like William suggests. From what I’ve seen, the problem is not so much the power of the PV being more than the generator, but moreso if the 1) generator is synchronous or non-synchronous with the inverted AC (sine wave) and 2) if the loads are less than the PV. The generator will ‘create’ the voltage and run even if there are zero loads. The inverted AC (from PV) wants to push current onto the ‘local grid’ and if there are no loads (nor heat sink diversion or batteries to charge) then the current will try to backfeed the generator. My recommendation is to get a critical loads panel for the generator only back-up, or go grid-tie with back-up using a Sunny Island, or the like, that make the switch seamless during an outage. *Greg Seelhorst* /Designer/Project Manager/ NABCEP Certified Solar PV Installer™ *POSITIVE ENERGY, Inc.* 510 S. Main Street Las Cruces, New Mexico 88001* *Cell: 575-650-1883 Office: 575-524-2030 FAX:575-915-1788 *g...@positiveenergysolar.com* mailto:g...@positiveenergysolar.com www.positiveenergysolar.com /www.positiveenergysolar.com *http://www.positiveenergysolar.com/images/stories/PE-logotype.png* http://www.positiveenergysolar.com/ ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Small PV system/experiment for kids
Jason, for 9-11 year-olds this curriculum may be useful as a starting point, and we've got some others for different age groups. http://fsec.ucf.edu/en/education/k-12/curricula/sm2/index.htm The solar powered system experiment is designed for a cell so we suggested the load be a small propeller. Obviously, this would be a bad idea with a 250W module since an unsuspecting kid would then be launched into space, but a small module and a pump could be a fun educational display. On 2012/12/12 9:08, Jason Szumlanski wrote: I have been approached by a local elementary school to develop a very small PV related experiment or system that is appropriate for children aged 9-11. Not having kids myself, I have no idea where to start with this. They are fine with mounting a PV panel on the roof, wall, or ground. They want something interesting and/or interactive that the students can monitor over time. Has anyone done something like this that would be suitable? Jason Szumlanski Fafco Solar ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] MPP Tracking Notes: Solectria PVI13kW, Module VMPs
Hi all, Just passing along a correction from Solectria on this issue. Since Dec 2010 these inverters have had a 205V+ window; apparently these units just had an old label on them. Dave On 2012/11/29 9:39, Dave Click wrote: Hi all, I did an inspection recently that had 3 Solectria PVI13kW units installed. I was surprised to note that the MPPT window on the nameplate was 225-380VDC, as the online spec sheet and manuals all note a 205-385VDC window. When I asked tech support about this, they replied that the window has been 225-380 for a while. The rep was surprised that the online documentation is wrong and since my inverter was almost a year old, it's apparently been wrong for a year. No update as of today either, even though it's been a few weeks since I called. So, just an FYI in case you're looking to spec those inverters. This inconsistency ended up being a big deal on this inspection, as the module manufacturer chose to custom-label each module with its actual output. Turns out that the actual VMP values were about 9% lower than the spec sheet indicated, which pushed the expected summer array VMP down to around 217VDC. I'm not sure how widespread this tolerance issue is, but since many manufacturers don't always provide flash test results, and UL 1703 allows these values to vary by as much as 10%, this is another good reason to try to max out your string sizes and stay as far as you can above the MPPT minimum voltage. These modules have a power tolerance of +/-3%, which they accomplish with higher current values that in some cases actually exceeded the 10% UL tolerance limit! After 20 years, the VMP on these modules will be about 20% lower than spec! Dave ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] MPP Tracking Notes: Solectria PVI13kW, Module VMPs
Hi all, I did an inspection recently that had 3 Solectria PVI13kW units installed. I was surprised to note that the MPPT window on the nameplate was 225-380VDC, as the online spec sheet and manuals all note a 205-385VDC window. When I asked tech support about this, they replied that the window has been 225-380 for a while. The rep was surprised that the online documentation is wrong and since my inverter was almost a year old, it's apparently been wrong for a year. No update as of today either, even though it's been a few weeks since I called. So, just an FYI in case you're looking to spec those inverters. This inconsistency ended up being a big deal on this inspection, as the module manufacturer chose to custom-label each module with its actual output. Turns out that the actual VMP values were about 9% lower than the spec sheet indicated, which pushed the expected summer array VMP down to around 217VDC. I'm not sure how widespread this tolerance issue is, but since many manufacturers don't always provide flash test results, and UL 1703 allows these values to vary by as much as 10%, this is another good reason to try to max out your string sizes and stay as far as you can above the MPPT minimum voltage. These modules have a power tolerance of +/-3%, which they accomplish with higher current values that in some cases actually exceeded the 10% UL tolerance limit! After 20 years, the VMP on these modules will be about 20% lower than spec! Dave ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] PVSYST or similar analysis needed
Carl, you may also be interested in HOMER-- free 2-week trial available of the latest version (after that, $99 per 6-month renewal, despite zero updates since Nov 2010). There's also the free legacy version that's a few years old. http://homerenergy.com/ On 2012/11/26 22:40, Carl Adams wrote: Hello Wrenches, I am in need of an analysis for a large battery backup system. I am looking for a sweet spot in PV array size and battery bank size. I need this modeled on a time of day basis, and evaluated monthly thru a full calendar year. I am told that PVSYST can perform such an analysis but I neither have the tool nor the experience using it to perform the modeling, so I am looking to hire the job out to someone who does. If any of you have the software and expertise to use it please contact me off list for more detailed requirements. With Regards Carl Adams, SunRock Solar. ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] 3 Phase With 2 Inverters?
I would agree that the imbalance at these power levels is not a major issue. If it appears that Phase A is most heavily-loaded, I'd install the inverters as A-B and A-C to help mitigate the existing imbalance. If you've got a lot of 1P loads on a 3P service-- lighting, office receptacles or whatever-- you could easily have a large imbalance on a regular basis. The 7kVA PV imbalance in your installation would happen extremely rarely. If this imbalance still makes you uneasy, then install three inverters and then a relay system to bring all the inverters down in case any of them fails. The SMA Power Balancer does this for their inverters and maybe some third-parties offer them too for these Fronius installs. This seems to make the most sense for decentralized systems with many string inverters, to ensure that a low phase voltage doesn't turn off a fraction of your inverters and cause a 100kVA imbalance. I've heard that some utilities have a max PV imbalance (calculated from the inverter ratings) of 6kVA. No utility to my knowledge requires an interconnection agreement for a 10kVA single-phase commercial water heater (to steal a Bill Brooks example) that would have a much stronger impact. Dave On 2012/11/27 15:14, penobscotso...@midmaine.com wrote: Hi Holt, We installed a commercial system a year ago for the National Park Service that was designed by a competitor (?) and signed off on by an engineer. It consisted of 13.2 kw of pv and two Fronius 7000 watt, 208 3 ph. inverters. It sounds a lot like what you are dealing with. I questioned the engineer on it and he said because the facility was so large (it was a large research and visitor campus for Acadia National Park with 20+ buildings)the transformer would never see the imbalance and therefore was not a problem. Fronius agreed, but prefaced that with the fact that it still was not recommended. I can say that we have had no issues or complaints at all since the installation in August of 2011 and they monitor it continuously. It would have been a far better design to use three Fronius 4.5 inverters at 3 ph. I drafted a letter (CYA letter) to the powers that be about my concerns (transformer imbalance) and they chose to go ahead with the installation. Nothing like government work...many more stories about this installation than anyone has time for here. Daryl DeJoy NABCEP Certified PV installer Penobscot Solar Design We were asked to inspect a GT system installed by others. Service is 208 3ph with two (?) Fronius IG 4500 208v inverters. The inverter panel is 3ph with two 2pole breakers - one each side of the buss bar in a A/B, B/C configuration (??). Called Fronius and they said it would work, but they don't recommend it. No other information was given as to why they don't. My electrician is very uncomfortable with doing work on this system as is (ME TOO!), so I am wondering if I might be able get some ammo to convince system owner to add a third inverter to get the system right. What problems might/will be encountered in this system if not modified? BTW - inverter LCD screens were crapped out, so we couldn't readily see if system was functioning properlyfrom metering, we think not. Holt E. Kelly Holtek Fireplace Solar Products 500 Jewell Dr. Waco TX. 76712 254-751-9111 www.holteksolar.com ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] EMT in attic
Nick, what the AHJ is telling you may actually be in reference to 250.97; for most PV output circuits (yes these are necessarily dc) this bonding requirement applies since array VOC 250 VDC. As Kent just pointed out, these dc conductors clearly don't meet the NEC definition of a service. 250.97 Bonding for Over 250 Volts. For circuits of over 250 volts to ground, the electrical continuity of metal raceways and cables with metal sheaths that contain any conductor other than service conductors shall be ensured by one or more of the methods specified for services in 250.92(B), except for (B)(1)... followed by an exception. Seems that FMC is OK as an EGC if your conductors have 20A OCPDs, which I imagine you do, but that FMC also can't be longer than 6' (see 250.118(5)). So I think your AHJ is probably right and I just learned something. If you're running a separate EGC anyway, you may want to ask why this bonding business is so important-- but I don't have an NEC reference on this to help you argue this. Maybe the AHJ would allow you to just run MC cable as the 2011 NEC allows. John Wiles is awesome. Someone on this list had to say it. DKC On 2012/11/8 23:22, Nick Vida wrote: Hi Wrenches, Thanks for you comments. Fun for the day is hearing they want to apply section 230 about service conductors and say that flex is not a metallic raceway because it is no good for bonding. They are defining the pv source circuits as a service. I am getting a distinct Wiles vibe here. I find it so annoying when they try to put out these distinctions with no code, no city ordinance and not even an internal memo, especially when they remain obstinate without going to the trouble to actually legitimize the interpretation. Dan- are the output circuits necessarily DC? I would have to look at NEC for a minute, but it doesn't seem to add up to me right now. Thanks, Nick Vida ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] graphic software for mac
DraftSight is a free AutoCAD clone (not just for Mac) that may be what you're looking for. On 2012/10/22 13:37, Jason Szumlanski wrote: I don't know if you want a 3D modeling program, but Sketchup is free and incredibly powerful. There is a Pro version also available with more advanced tools. It's about as simple as 3D could be. You could do 2D with it also. I just got back from Sketchup 3D Basecamp, and saw some amazing things architects are doing with it. *Jason Szumlanski* /Fafco Solar/ On Thu, Oct 18, 2012 at 3:04 PM, Jonathan Hill solar...@gmail.com mailto:solar...@gmail.com wrote: Dear fellow wrenches- I'm looking for a good, simple drawing program for mac. I need it for pv system layouts. Free if possible. Any suggestions? Jonathan Hill, senior system engineer and founder *Sierra Solar Systems* ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Ten K Solar
This is possible because they have cell-level MPPT. I'd guess that even when the sun is perpendicular to the module you'd have a [tiny] bit of extra current from diffuse light reflected onto the module, and you'd see more substantial gains from reflection if the sun can see the reflector and PV. I don't think this would be enough to outperform a 2-axis tracker, but it's an interesting approach to maximizing kWh/kW. On 2012/10/22 18:23, Chris Mason wrote: Do we really buy that a reflector panel will produce more power than just laying the solar pv at the right tilt? ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Utility inverter rating
Erika, I think the takeaway here is that the Island only has that surge power capacity on the protected load side- you wouldn't see this surge on the utility side. SMA should be able to provide this sort of documentation for you. On 2012/10/18 9:38, Erika Weliczko wrote: Greetings all. I recently received this back regarding an interconnection application proposing a Sunny Island 6048 and a SB7000: “we have to rate the system at the max output of the inverters, and since that battery backup has an inverter that can export 11kW, (albeit for 3 seconds) I have to review the system for a total of 18kW.” This is a new one on me. I might argue that the SB7000 is upstream of the SI6048 and really the SI6048 is the point of interconnection, so the SB7000 is irrelevant. And 3 seconds is not really continuous operation. It seems that batteryless inverters show continuous output ratings, though I know there are some that specify a larger than expected OCP for various reasons, but that is not what the utility cares about. Any insights here? Thanks, Erika REpower SOLUTIONS www.repowersolutions.com P: 216.268.2275 C: 216.402.4458 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] SunnyIsland - was AC coupling and Outback inverters
Check out the new SMA Smartformer, though I'm not sure whether it's actually shipping yet. I'm thinking about this for my house eventually (SB5000US). http://www.sma-america.com/en_US/products/off-grid-and-back-up-solutions/smartformer-for-sunny-island.html Alternatively, the new SMA TL inverters (at least the 3, 4, and 5kW units according to the press release) have an Emergency Power Supply function that can provide backup power (12A?) during the day when the grid is down. This may meet your customer's requirements. No batteries required, though since the TLs require ungrounded arrays, you may need to rewire the existing array to be compliant with 690.35 (PV Wire or raceway). On 2012/10/5 8:41, Kirk Herander wrote: One Question: Output of the SunnyBoy is 240vac. So this is fed to the critical load panel, of which the SunnyIsland 120 vac output is fed to. So we need a 120/240 step up transformer between the SunnyIsland and the critical load panel to fully take advantage of the Sunnyboy array for battery charging, correct?. Kirk Herander VT Solar, LLC dba Vermont Solar Engineering NABCEP^TM Certified installer Charter Member NYSERDA-eligible Installer VT RE Incentive Program Partner 802.863.1202 *From:*re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *David Katz *Sent:* Friday, October 05, 2012 2:11 AM *To:* RE-wrenches *Subject:* Re: [RE-wrenches] AC coupling and Outback inverters Hi Kirk, All of the Outback inverters will work AC coupled (GT and FX) as will any bi-directional H-bridge type inverter. I have used old Trace SW’s, SunnyIsland, Apollo TSW, Magnum AE and now I am using an Outback Radian to do exactly what you are talking about. I have 6 kW of grid tie inverter and an additional 4kw of modules running through a Xantrex 600 volt charge controller to the batteries that the Radian runs on. It all works flawless as long as you have a provision for protecting the batteries when the gid is down and the grid-tie PV system is making more power than the loads are using. If the customer has SMA inverters, I would recommend using a SunnyIsland because the battery control when the grid goes down is so elegant. Everything else is a bit of a kludge. David Katz CTO Founder AEE Solar Inc P: 707 825-1200 F: 707 825-1202 dk...@aeesolar.com mailto:dk...@aeesolar.com www.aeesolar.com http://www.aeesolar.com *From:*re-wrenches-boun...@lists.re-wrenches.org mailto:re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] mailto:[mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *Kirk Herander *Sent:* Thursday, October 04, 2012 2:11 PM *To:* RE-wrenches *Subject:* [RE-wrenches] AC coupling and Outback inverters I have AC-coupled an Outback quad-stack with multiple SunnyBoy 6000US inverters and it’s been running fine for 4 years. I used the off-grid version of Outbacks. Now I have an application where a customer wants to add battery backup to an existing SunnyBoy 5000US system. And expand his array by a couple KW. So I’m thinking of using a GT Outback w/ batteries to handle the critical loads and feed the extra 2kw of PV (charging the batteries through an MX60) to the grid. And I’d like to AC-couple the SunnyBoy so the original 5 kw array can also charge the batteries, BUT I remember, at least I think so, that the GT inverter cannot be AC-coupled, only the off-grid version. Is this correct? Thanks. Kirk Herander VT Solar, LLC dba Vermont Solar Engineering NABCEP^TM Certified installer Charter Member NYSERDA-eligible Installer VT RE Incentive Program Partner 802.863.1202 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] BIPV Options
Good input on the Atlantis options-- does anyone have experience with the www.bipvinc.com or www.lumetasolar.com products? On 2012/10/2 13:06, Robert Evans wrote: I installed the BOS for an Atlantis Sunslates system back in 2003-04, and commissioned the system. Based on my experience I couldn't recommend them, unless they have fixed the product. The customer had already contracted with Atlantis and an approved roofer to install the Sunslates on his residence. I was around during the install of the slates and while indeed time consuming it actually went pretty smoothly and looked good. I was worried though when I saw all the series connectors and realized that the system didn't offer any airflow under the slates. The system performed subpar right out of the gates (as compared to framed mods on racks) - especially during the summer on hot days - remember there was no airflow. However after just 2 years the system production really nosedived (50% of similar framed mod system) due to poorly designed connectors (not MC type but funky cam-closures that I had never seen before) that built up high resistance connections and slates that failed due to poor internal connections. Troubleshooting was very difficult due to poor access to the connections. Atlantis did send people out often over the years to try and correct the situation, and they added more slates to the roof to compensate for the poor production. But the system continually had problems, and the customer never really got any satisfaction. It's actually way to long a story to tell here. I think BIPV always has these challenges inherent: Expensive product. Expensive labor intensive install. Lots of connections. Difficult access to connections. Poor airflow and hot operating cell temps. Well designed products can help mitigate these. Poor designed products make these issues worse. There is a reason why BIPV has not proliferated on residential buildings. Maybe Atlantis has fixed these issues? I was never interested in promoting the product so I've never looked into it. But anyone looking to put this product up should really do some homework. And one more thing - anytime a customer gets a system installed from 2 parties - one for the array and one for the BOS, it becomes difficult for all involved should the system not perform well. I learned a lesson and never got involved in a split up job like this in the future. Bob Evans NABCEP Certified PV Installer Evans Energy Systems Santa Cruz, CA 831-345-3459 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] BIPV Options
Sorry, to clarify I meant the Lumeta tiles for sloped roofs. I think they were at SPI two years ago but I didn't notice them this year if they were at the show. On 2012/10/2 15:27, hol...@sbcglobal.net wrote: Having installed Powerlight systems, I would shy away from flat arraysdirty, dirty dirty Holt E. Kelly Holtek Fireplace Solar Products 500 Jewell Dr. Waco TX. 76712 254-751-9111 www.holteksolar.com - Original Message - From: Dave Click davecl...@fsec.ucf.edu To: re-wrenches@lists.re-wrenches.org Sent: Tuesday, October 02, 2012 1:22 PM Subject: [RE-wrenches] BIPV Options Good input on the Atlantis options-- does anyone have experience with the www.bipvinc.com or www.lumetasolar.com products? On 2012/10/2 13:06, Robert Evans wrote: I installed the BOS for an Atlantis Sunslates system back in 2003-04, and commissioned the system. Based on my experience I couldn't recommend them, unless they have fixed the product. The customer had already contracted with Atlantis and an approved roofer to install the Sunslates on his residence. I was around during the install of the slates and while indeed time consuming it actually went pretty smoothly and looked good. I was worried though when I saw all the series connectors and realized that the system didn't offer any airflow under the slates. The system performed subpar right out of the gates (as compared to framed mods on racks) - especially during the summer on hot days - remember there was no airflow. However after just 2 years the system production really nosedived (50% of similar framed mod system) due to poorly designed connectors (not MC type but funky cam-closures that I had never seen before) that built up high resistance connections and slates that failed due to poor internal connections. Troubleshooting was very difficult due to poor access to the connections. Atlantis did send people out often over the years to try and correct the situation, and they added more slates to the roof to compensate for the poor production. But the system continually had problems, and the customer never really got any satisfaction. It's actually way to long a story to tell here. I think BIPV always has these challenges inherent: Expensive product. Expensive labor intensive install. Lots of connections. Difficult access to connections. Poor airflow and hot operating cell temps. Well designed products can help mitigate these. Poor designed products make these issues worse. There is a reason why BIPV has not proliferated on residential buildings. Maybe Atlantis has fixed these issues? I was never interested in promoting the product so I've never looked into it. But anyone looking to put this product up should really do some homework. And one more thing - anytime a customer gets a system installed from 2 parties - one for the array and one for the BOS, it becomes difficult for all involved should the system not perform well. I learned a lesson and never got involved in a split up job like this in the future. Bob Evans NABCEP Certified PV Installer Evans Energy Systems Santa Cruz, CA 831-345-3459 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] 120% rule applying to conductors
Mr. Brooks had an email on this topic on 5/8, 12:58pm ET. NEC officially says that the conductor needs to be upsized but the 2014 will fix it because that is dumb. I've copied some of Bill's email below. ** The key distinction was used in my proposal to the 2014 NEC that removed the statement “and conductor” in 705.12(D) since conductors are treated very differently in the NEC. We in 690 are the ones that got this messed up. The issue with conductors are taps. With two sources feeding a tap, the sum of the feeder breakers would have to be taken into account in sizing the tap. This does NOT mean that the tap is a full size conductor. The tap rule determines the size and the new proposal simply requires you to use both the feeder breaker and the PV breaker in sizing the tap. This assumes that both breakers are feeding the tap in the event of fault on the tap and that there would be no problem clearing that fault. If fault current was used as an argument for oversizing (it is wrong), it only has relevance in the tap scenario. A fault in a feeder with no taps does not allow the sum of the currents to flow anywhere but where the fault is—the rest of the conductor is undamaged in a fault. ... Sizing a conductor for the sum of two breakers on opposite ends of a feeder seems to be what the code says, but it is totally ABSURD from a technical point of view. John’s articles were merely pointing out that the code language seems to be telling us to do this, regardless of whether it makes technical sense. The 2014 NEC will do away with this craziness. ** On 2012/9/28 9:46, Kristopher Schmid wrote: It seems to me that the conductor should not be subject to the 120% rule despite what the code says. The potential safety issue here is overloading the neutral bus, right? While feeding currents could be additive in the panel, they would be subtractive on the feeder, no? I seem to remember seeing this discussion on the list before. Kris On Fri, Sep 28, 2012 at 8:26 AM, Aaron Mandelkorn reoso...@gmail.com mailto:reoso...@gmail.com wrote: I agree. With a 150A bus being fed by 100A from the grid leaves 80 additional amps (120% of 150A) to feed the bus from outside sources. It seems to me that 40A of PV being back fed will be just fine. Aaron Mandelkorn NABCEP Certified PV Installer Renewable Energy Outfitters Box 65 Salida, CO. 81201 (970)596-3744 tel:%28970%29596-3744 reoso...@gmail.com mailto:reoso...@gmail.com www.reosolar.com http://www.reosolar.com On Sep 28, 2012, at 6:32 AM, Drake wrote: Are you sure you can't? Since the bus has a rating of 150 A and is protected by a 100 A breaker, there is plenty of room to not over amp the bus from the two sources of power. The amperage from the inverter will cancel amperage coming from the utility in the feeder. The wire will never supply over the 100 A. The theoretical max the inverter could backfeed would be 40 Amps in the 100 Amp cable if no loads were being supplied. It would certainly not be a safety issue. Am I missing something in the code? At 12:51 AM 9/28/2012, you wrote: Mac: Nope. William Miller PS: It's pretty straight forwards, the code says bus or conductor. wm PPS: Can you customer live with a smaller feeder breaker, say 125 amps? If so, your gold. wm At 06:43 PM 9/27/2012, you wrote: Hello wrenches, I am looking for advice on how the 120% rule applies to feeders for a subpanel. I have this scenario: 150A bus rating on subpanel with main breaker of 100A. The conductors feeding this subpanel are 100A rated conductors. Can I backfeed with a 40A breaker? Thanks -- Mac Lewis *Yo solo sé que no sé nada. -Sócrates * ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm http://www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org http://www.members.re-wrenches.org/ Internal Virus Database is out of date. Checked by AVG - www.avg.com http://www.avg.com/ Version: 8.5.455 / Virus Database: 271.1.1/5272 - Release Date: 09/16/12 18:34:00 Miller Solar Voice :805-438-5600 tel:805-438-5600 email: will...@millersolar.com mailto:will...@millersolar.com http://millersolar.com http://millersolar.com/ License No. C-10-773985 ___ List sponsored by Home Power magazine List Address:
Re: [RE-wrenches] Short Circuit Cell Damage
Short-circuiting should be OK for crystalline cells, but some thin film manufacturers ask you not to do this. On the jumper-cutting, I agree with the others that you probably shouldn't create arcs just for fun! On 2012/9/17 23:50, Mark Frye wrote: Wrenches, True or False: In a nominal sort of grid tied situation with string Voc at about 300 VDC and Isc at about 6 or 7 amps..It is OK to install modules on a roof in the sun and short the pos and neg together indefinitely. In other words modules can handle operating at Isc continuously without damage. It is only if you get localized shading AND a failed bypass diode that damaging hot spot heating can lead to failure? I am reviewing an installation manual that recommends completing the home run by connecting the pos and neg of the string with a single jumper cable, folding the cable on itself in order to push it through to a j-box and at some point later on, cutting the jumper in the j-box to terminate the pos and negs to the home run. I am concerned both about maintaining the string in a short circuit condition and cutting the jumper while energized. Any thoughts? Mark Frye Berkeley Solar Electric Systems ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Up for a 1-Line Riddle?
I've seen that one a lot, too. And not to quibble, but the 1-line depicts this correctly (no inline fuse shown in the inverter DC disconnect box), though there should be a note making this more explicit. Speaking of sunny days turning off the system, how about the 3 30A inverter breakers' combined feed going into a 55A breaker. Also... a 55A breaker? Really? I guess the designer wanted to leave a little headroom to avoid scaring the 60A disconnect. DKC On 2012/8/30 14:35, Andrew Truitt wrote: Ahh yes, the old combine strings before landing on a fused DC input terminal trick. Sure to blow the fuse the first sunny day. This is why SMA created their fuse-bypass DC input terminal. I take it the installer was not aware of this... For a brighter energy future, Andrew Truitt NABCEP Certified PV Installer™ (ID# 032407-66) Principal Truitt Renewable Energy Consulting (202) 486-7507 tel:%28202%29%20486-7507 http://www.linkedin.com/pub/andrew-truitt/8/622/713 Don't get me wrong: I love nuclear energy! It's just that I prefer fusion to fission. And it just so happens that there's an enormous fusion reactor safely banked a few million miles from us. It delivers more than we could ever use in just about 8 minutes. And it's wireless! ~William McDonough On Thu, Aug 30, 2012 at 11:53 AM, Jason Szumlanski ja...@fafcosolar.com mailto:ja...@fafcosolar.com wrote: I was sent to look at another contractor's work, and found three SB5000 inverters with blown string input fuses. I was able to determine the reason pretty quickly, and was later sent the original 1-Line, which was installed per the drawings. The 1-Line came from a leading system integrator who shall remain nameless. See anything wrong? https://www.sugarsync.com/pf/D6539806_8669786_010829 Just goes to show you - the contractor needs to take responsibility and verify the specifications are correct, safe, and code compliant. Jason Szumlanski Fafco Solar ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm http://www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org http://www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Up for a 1-Line Riddle?
Thanks David, I was in residential mode and just saw the 240V listed in the OCPD table! On 2012/8/30 16:47, David Brearley wrote: I'm assuming it's a balanced 3-phase interconnection, which fits with the reported phase current of 42 A: (3 x 5000 W) / 208 V / 1.73 = 41.7 A Or more simply: 24 A per inverter x 1.73 = 41.5 A However, no one reviewing a single-line should have to guess about the service type On Aug 30, 2012, at 3:12 PM, Dave Click wrote: I've seen that one a lot, too. And not to quibble, but the 1-line depicts this correctly (no inline fuse shown in the inverter DC disconnect box), though there should be a note making this more explicit. Speaking of sunny days turning off the system, how about the 3 30A inverter breakers' combined feed going into a 55A breaker. Also... a 55A breaker? Really? I guess the designer wanted to leave a little headroom to avoid scaring the 60A disconnect. DKC On 2012/8/30 14:35, Andrew Truitt wrote: Ahh yes, the old combine strings before landing on a fused DC input terminal trick. Sure to blow the fuse the first sunny day. This is why SMA created their fuse-bypass DC input terminal. I take it the installer was not aware of this... For a brighter energy future, Andrew Truitt NABCEP Certified PV Installer™ (ID# 032407-66) Principal Truitt Renewable Energy Consulting (202) 486-7507 tel:%28202%29%20486-7507 http://www.linkedin.com/pub/andrew-truitt/8/622/713 Don't get me wrong: I love nuclear energy! It's just that I prefer fusion to fission. And it just so happens that there's an enormous fusion reactor safely banked a few million miles from us. It delivers more than we could ever use in just about 8 minutes. And it's wireless! ~William McDonough On Thu, Aug 30, 2012 at 11:53 AM, Jason Szumlanski ja...@fafcosolar.com mailto:ja...@fafcosolar.com wrote: I was sent to look at another contractor's work, and found three SB5000 inverters with blown string input fuses. I was able to determine the reason pretty quickly, and was later sent the original 1-Line, which was installed per the drawings. The 1-Line came from a leading system integrator who shall remain nameless. See anything wrong? https://www.sugarsync.com/pf/D6539806_8669786_010829 Just goes to show you - the contractor needs to take responsibility and verify the specifications are correct, safe, and code compliant. Jason Szumlanski Fafco Solar ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm http://www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org http://www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Enphase M210-84-208-S12 Inverters Available?
Enphase already positive-grounds the module: http://enphase.com/support/installation-wiring/ Q: The Enphase Microinverter manual states that the device is positively grounded. Don't most PV modules have negative grounds? Is this a problem for Enphase? A: Enphase made the decision to positively ground its microinverters to minimize corrosion. Because Enphase Microinverters are positively grounded, they are compatible with both positively and negatively grounded modules. On 2012/8/12 13:29, JRQ wrote: Louis, Can Enphase inverters be positively grounded? I wasn't aware that they could. Otherwise you have an equipment mismatch problem that can't be overcome under the listing of the modules and the inverters. Jeffrey Quackenbush. *From:* Louis Woofenden lo...@woofenden.net *To:* RE-wrenches re-wrenches@lists.re-wrenches.org *Sent:* Tuesday, August 7, 2012 2:54 PM *Subject:* [RE-wrenches] Enphase M210-84-208-S12 Inverters Available? Hi Wrenches, I'm trying to piece together an SunPower/Enphase job, and looking for up to 25 Enphase M210-84-208-S12 inverters, which have been discontinued by Enphase. If you happen to have any available (or know someone who does), can you please contact me off-list at lo...@netzerosolar.net mailto:lo...@netzerosolar.net, or 520-237-5040? Thanks, Louis Woofenden Net Zero Solar, LLC Tucson, AZ ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] mounting hardware and U.L.
http://solarabcs.org/about/publications/reports/module-grounding/index.html (see the Issues Recommendations report) Phil is right that UL 2703 isn't finalized yet so it's not actually a requirement. However, I imagine that module installation manuals and UL 1703 will both refer to 2703 soon, so it's not something that you'll be able to ignore forever either. Since 2703 still isn't approved (see: http://www.ul.com/global/eng/pages/solutions/standards/accessstandards/catalogofstandards/standard/?id=2703_1 ), I don't see how Unirac can claim that they have an ETL mark for 2703. Ray is right that an AHJ can't reasonably require equipment that doesn't exist. Just as NEC 2011 690.11 doesn't require you to use string inverters with arc fault protection, since no such unit is available (well, at least until SMA just started offering this for their standard low-freq Sunny Boys)-- no inspector should require anything listed to UL 2703 yet. A relevant section is 90.4 (this section is copied from 2008). ** The authority having jurisdiction for enforcement of the Code has the responsibility for making interpretations of the rules, for deciding on the approval of equipment and materials, and for granting the special permission contemplated in a number of the rules. By special permission, the authority having jurisdiction may waive specific requirements in this Code or permit alternative methods where it is assured that equivalent objectives can be achieved by establishing and maintaining effective safety. This Code may require new products, constructions, or materials that may not yet be available at the time the Code is adopted. In such event, the authority having jurisdiction may permit the use of the products, constructions, or materials that comply with the most recent previous edition of this Code adopted by the jurisdiction. ** On 2012/7/20 0:52, Marco Mangelsdorf wrote: Thanks, Phil. I just went to that website and do not know exactly what report you're referring to. Could you please provide the link? marco I don't think it's formally ratified, certified and adopted, but UL2703 is the new proposed Standard for Mounting Systems, Mounting Devices, Clamping/Retention Devices, and Ground Lugs for Use with Flat-Plate Photovoltaic Modules and Panels. Also check out SolarABCs.org for an update, there is a new report on this topic. Phil On Thu, Jul 19, 2012 at 4:12 PM, Jay Peltz j...@asis.com wrote: Is unistrut UL? Kay Peltz power Sent from my iPhone On Jul 19, 2012, at 6:36 PM, Marco Mangelsdorf ma...@pvthawaii.com wrote: Does anyone know whether there are U.L. standards when it comes to PV mounting hardware? That is, are there any mounting hardware manufacturers (UniRac, Professional Solar Products, DPW, Schletter) who have achieved U.L. listing/approval for their stuff? After using PSP for the past 12 years here on the Big Island of Hawaii, now, all of a sudden the new building division head is taking an interest as to whether PSP hardware is U.L. something or other. So very frustrating Thanks, marco ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings:
Re: [RE-wrenches] DC GEC Sizing Issue - Water Main GE
Garrison, If you're doing a small commercial grid-tie system, your inverter GEC requirements are determined not by the service size but by your inverter. To illustrate, if you were installing a single Enphase, running an unspliced #3/0 copper wire from your pipe up to your inverter would be overkill, right? 690.47(B) is for systems with DC requirements only (e.g. small inverter-free stand-alone systems). If you're on the 2011 NEC, the simplest way to do this is to run a combination EGC/GEC from the inverter GEC terminal *unspliced* through your AC conduit to the ground bus of your interconnection panelboard, sizing it to meet DC GEC and AC EGC requirements. If you're on the 2008 and your inspector won't allow you to use the 2011 method, you'd run and size your AC EGC as you normally would. For your GEC you would size that based off the larger of 250.66 or 250.166, and note that 250.166(B) doesn't apply since you have a pipe electrode (250.166(C) overrides 166(B)). So you can get away with a #6 copper GEC unspliced from your inverter to your pipe. Run that GEC in PVC conduit if you can, but if the site requires you to use metal, you'll need to bond both ends. To answer your questions: 1. Per 2008, you'll size the GEC per 250.66 and 250.166, and the .166 requirement will likely win out. Per 2011, you'll size your combined EGC/GEC as no smaller than 250.122 or 250.166. 2 3. Largest conductor applies to the largest conductor in the PV system (likely your homerun DC). Dave On 2012/7/20 15:06, Garrison Riegel wrote: Wrenches, I have GEC sizing issue and would greatly appreciate any advice you can share. We have a small commercial grid-tie system installing on a facility with a 4000A, 240V, 3Ph service that uses the water main as the Ground Electrode. My engineer is referencing NEC Table 250.66 (and the 4000A service entrance cables) to size the GEC from the inverters to the GE, and therefore is requiring a 3/0 (maximum size required by this table). Since this is actually a DC GEC, I think it should be sized according to NEC 690.47(B) which references 250.166. Since the GE is a water main it seems that 250.166(B) would apply, requiring the GEC “/shall not be smaller than the largest conductor supplied by the system.” /If taken literally, the largest conductor supplied by the system could be the 4000A service entrance cables, which would require a GEC even larger than the seemingly excessive 3/0. For obvious reasons I hesitate to mention this to my engineer, but I in the end I want to do what is best. // My questions: // 1.Is my engineer correct, and we should size the GEC according to 250.66? 2.If #1 is no, and 250.166(B) does apply, is “the largest conductor supplied by this system” the 4000A service entrance cables, and the GEC size should match these? 3. Or, since 250.166 is written for DC systems, is this “largest conductor” the DC source circuit conductors (#10 in this case), and therefore the GEC can be a #8 (smallest size allowed)? Thank you in advance, Garrison Garrison Riegel Project Manager *Solar Service Inc* [p] 847-677-0950 www.solarserviceinc.com http://www.solarserviceinc.com/ NABCEP Certified Solar PV and Thermal Installer™ ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] roof attachment in tile roof
As a note for tile roofs: the tile keeps most of the water on top of it but it's not the actual sealed layer. The underlayment is the true waterproofing layer, so be sure you seal the penetration through the underlayment as well as the hole you cut in the tile. On 2012/7/18 23:42, Parrish, Peter wrote: That's the link. Yes, that is the big advantage IMHO. If you use a 7/16 masonry drill (as I remember) there is scant clearance between the resultant hole and the 3/8 SS all thread. I use a liberal amount of Sika 1A caulk around the annular ring and regular SS 3/8 washer on top of that. In southern California we have lots of flat concrete tiles (even easier) as well as S-tiles. I think there still is an app note on their website. Keep the bit cool by dunking it in a cup of water between holes. - Peter *From:* re-wrenches-boun...@lists.re-wrenches.org [re-wrenches-boun...@lists.re-wrenches.org] on behalf of benn kilburn [b...@daystarsolar.ca] *Sent:* Wednesday, July 18, 2012 4:48 PM *To:* RE-wrenches *Subject:* Re: [RE-wrenches] roof attachment in tile roof Peter, Do you have a link to the tile track you referred to. Is it the one spelled Tile Trac found at this link TileTrac http://www.prosolar.com/old_sitepages/tile_trac_index.htm This is nice as it has the flexibility to locate the bolt at the top of the tile when the rafter doesn't line up. But it relies on the bolt going thru the tile at the high point (and some sealant) for keeping water out? Benn DayStar Renewable Energy Inc. www.daystarsolar.ca * Ph: 780-906-7807 Construction Electrician Solar Photovoltaic Systems Certified Certificate # 0007S HAVE A SUNNY DAY On 18/07/12 2:44 PM, Parrish, Peter peter.parr...@canyons.edu mailto:peter.parr...@canyons.edu wrote: All the hooks I have tried caused the tile to “pop up” and to avoid this one has to notch the tile. More trouble than it is worth IMHO. Tile track works well and doesn’t need flashing. Peter Parrish College of the Canyons peter.parr...@canyons.edu mailto:peter.parr...@canyons.edu O: (661) 362-3888 C: (323) 839-6108 - *From:*re-wrenches-boun...@lists.re-wrenches.org mailto:re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *Benn At DayStarSolar *Sent:* Wednesday, July 18, 2012 8:38 AM *To:* RE-wrenches *Subject:* Re: [RE-wrenches] roof attachment in tile roof William, Jason; I appreciate the suggestion, it sounds like an ideal solution. I do wonder why you prefer posts when you could use the tile hooks and avoid the extra work and time of cutting and flashing? If it makes for a better attachment structurally and weather-proof wise, then I'm all for it. Could you make a few points for/against tile hooks vs flashed posts? Thanks. benn Sent from a 'smart' phone, with tiny keys. Please excuse shortcuts and typos. On 2012-07-13, at 2:20 PM, Jason Szumlanski ja...@fafcosolar.com mailto:ja...@fafcosolar.com wrote: I should have mentioned that a few manufacturers make complete standoff and flashing systems: http://www.quickmountpv.com/products/universal-tile-mount.html#page=overview http://www.verde-industries.com/solar-flashings/solar-flashings.html There are others. Jason Szumlanski Fafco Solar On Fri, Jul 13, 2012 at 4:12 PM, Jason Szumlanski ja...@fafcosolar.com mailto:ja...@fafcosolar.com wrote: Agreed. AKA Stand-offs. Unirac makes two-piece standoffs in 4-7. Two lags per base make a highly secure connection to the truss. NRCA Flashing detail http://www.nrca.net/consumer/types/details/tile-7.pdf Jason Szumlanski Fafco Solar On Fri, Jul 13, 2012 at 2:18 PM, William Miller will...@millersolar.com mailto:will...@millersolar.com wrote: Benn: None of the below. Use stanchions, also known as power posts. Flash them properly, just like a roof vent, only they will be perpindicular to the roof surface, not vertical. William Miller At 06:40 AM 7/13/2012, benn kilburn wrote: Hanger bolts or tile hooks….What does the collective wisdom of this list have to suggest/recommend? Cheers, Benn DayStar Renewable Energy Inc. ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm http://www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org http://www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address:
Re: [RE-wrenches] L feet no flashing in shingle roof
I always thought that installing lag screws was tough enough with pilot holes- I should hit the gym. I'm not a structural PE, but I think that not drilling pilot holes violates the American Wood Council's National Design Specs and therefore violates the IBC too. I would imagine that you'd be much more likely to split your trusses. IBC also requires flashings be used but at least around here inspectors never ask for it (which makes sense- as you all know, Florida never sees wind or rain, and definitely not at the same time). What silicone do you use that's compatible with asphalt shingles? DKC On 2012/7/1 21:13, m...@hurshtown.com wrote: In my 20 year experience of lagging down L feet on shingle roofs in Indiana with a good dollop of silicone caulk under the foot, I've never had an issue. No pre-drilling, just drive the lag home. Drilling a hole first is not necessary, and reduces holding strength. No reason to make a science project out of it and increase cost and labor. Mark Original Message Subject: Re: [RE-wrenches] L feet no flashing in shingle roof From: Drake drake.chamber...@redwoodalliance.org mailto:drake.chamber...@redwoodalliance.org Date: Fri, June 29, 2012 3:09 pm To: RE-wrenches re-wrenches@lists.re-wrenches.org mailto:re-wrenches@lists.re-wrenches.org Hi Jay, There is no room for flashings. The L feet will go very close to the skylights and the flashing would hit the edge of them. Plus there is an existing array that was done by another installer that is done with L feet only. The new array would be higher. And given that we have really good off the shelf approved flashed feet, why would you use anything else? My 2 cents, Jay peltz power On Jun 29, 2012, at 5:16 AM, Glenn Burt wrote: We have used a variety of sealants over the years, and determined simple Henry roofing cement is the best product for use on comp roofing. We also used to bend our own L-foot flashing, which we cut from standard Al coil stock (before all the manufactured options were available). This might be a good option for you in this case. Glenn *From:* re-wrenches-boun...@lists.re-wrenches.org mailto:re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *Drake *Sent:* Thursday, June 28, 2012 6:40 PM *To:* RE-wrenches *Subject:* [RE-wrenches] L feet no flashing in shingle roof I'm quoting a job that has an existing array with L feet bolted down to a shingle roof with no flashings. I want to match the height of the existing array. Also some modules are being worked in around skylights where it is unlikely that room would be available for flashings to center over rafters. I've always used flashings. Would it be completely crazy to follow suit of the existing array and bolt L feet straight to the shingle roof with good roof sealant? If so, how would you seal it? Drake Chamberlin ATHENS ELECTRIC LLC OH License 44810 CO license 3773 NABCEP Certified PV ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm http://www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org http://www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Solar Attic Fans
We did a paper on this back in 2000 that folks may find interesting. A bit outdated- two 10W (thin film) fans were used for a 1000 sf home. http://www.fsec.ucf.edu/en/publications/html/FSEC-GP-171-00/index.htm Conclusion: Comparing periods with similar weather conditions, the test revealed that the PV vent fans have the potential to reduce measured peak summer attic air temperatures by over 20oF. However, the impact over the cooling season is fairly modest with well insulated attics. Measured space cooling reduction was approximately 6% - worth about 460 kWh annually at the test home. [test home had R-19 ceiling insulation] On 2012/6/8 12:09, Carl Adams wrote: Fellow Wrenches, I have had several prospects and customers ask about installation of solar attic fans. One customer had a roof replacement prior to our PV install and the roofing contractor installed a solar attic fan. I could not make out any name brand on the unit, but it was quite noisy for a brand new device. Makes me wonder about it's longevity. Have any of you a good quality brand you would recommend for those customers who are interested? With Regards Carl Adams, SunRock Solar ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Finding ground faults
Here's the Paul Mync / John Berdner article from SolarPro 2.5: http://solarprofessional.com/article/?file=SP2_5_pg60_Mync -David Brearley... er... Click On 2012/5/22 22:36, Bob Clark wrote: Wrenches: Sorry to bring up this situation again, but I could not find a previous discussion thread that talked about step-by-step procedures for tracking down ground faults (I believe it was John Berdner who provided the bulk of the writing in that regard and it related to high voltage strings—not that 75-85 volts per string is all that low). We have an Outback FLEXpower Two system with 8, 3-module strings (Silicon Energy 190W, 25.3Vmp, 7.5 Imp) combined in a Midnite Solar MNPV12 combiner with breakers. The cables from the array are routed to two different Wiley 4-string pass-through boxes (located under the two center strings) and then off of the roof and into the PV combiner. Up until this week the system has seen several weeks of awesome power production. Yesterday, the rains came and the GFDI breaker tripped. Every time it rains, the little green breaker on the GFDI trips off. That tells me that the ground fault is occurring in a place where at least one of the conductors on one of the strings (possibly more) is getting wet and conducting current to ground. It would seem to me that the most likely place for moisture to cause a ground fault to occur in this system would be in the pass-through boxes. This would mean removing the central modules to access the pass-through boxes. Any of you who have mounted the Silicon Energy modules know that the cables are contained in trays along the side of the modules until they are routed through conduit to the pass-through boxes. So, if there is current going to ground from any of these cables, it could even be occurring in any of the 9 trays along side of the modules. I do not like the idea of tracking down a ground fault in one of these trays as they are all interconnected. How best (and safely) to track down where the ground fault is occurring? Any advice as to the best and safest way to track down the ground fault(s) would be greatly appreciated. *Bob Clark* */SolarWind Energy Systems, LLC/* ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Line side taps in Hawai'i
Square D probably has a similar solar-ready panel; I remember seeing some monster (4' tall? they were big) Cutler Hammer panelboards at SPI 2010 that had it too. On my house I have a Square D RC2M200S which has simply a 200A main plus a 2P 50A breaker (perfect for PV). This is a much smaller enclosure (18H x 20W) than some others I've seen, but with limited functionality; no load breakers can be added here which can be a problem when using it in a retrofit. This is an issue for the combination service entrance devices as the conductors from the utility meter load terminals to the main breaker are factory-installed and can't be touched. I did an inspection two years ago where the installing contractor's solution was to interconnect the PV on the utility side of the meter. This is not a solution. If the issue is that nobody is allowing line side connections then you're sorta stuck. As for why the AHJ wouldn't allow it, they should be willing to share their justification with you! If the issue is as Jeffrey's encountered-- they're requiring listed enclosures where line-side connections are made-- then you can get around it either with these Milbank dual lugs http://www.milbankmfg.com/products/Catalogs/CatalogFiles/PDF/K4977.pdf#Tap%20Connector or the aforementioned Cutler Hammer or Square D panels. It may be that they've heard about the listed enclosure requirement and naively generalized it beyond code requirements. If they're asking for service upgrades, then perhaps they're thinking that a 200A service + 100A PV requires a 300A service-- if it's not battery backup, a simple power flow diagram may prove to them that a 200A service is perfectly adequate. On 2012/5/19 17:52, JRQ wrote: I had a similar problem working in San Diego. SDGE insisted that no taps could be performed in an enclosure unless the contractor could supply documentation that the enclosure was specifically listed for a tap, or if an electrical engineer supplied stamped drawings of the tap. I never did a project that warranted hiring an engineer, so I don't know what they were looking for there. I heard that Square D (or maybe it was one of the other companies) has a new solar-ready service panel with a lug on the line side for a solar input. You could use the same feeders and service size with a new panel. Jeffrey Quackenbush NABCEP certified PV installer Peripatetic Solar Technician *From:* James Rudolph jamesrudolp...@gmail.com *To:* RE-wrenches re-wrenches@lists.re-wrenches.org *Sent:* Wednesday, May 16, 2012 10:48 PM *Subject:* [RE-wrenches] Line side taps in Hawai'i Aloha Wrenches, I have recently started working in Hawaii on the island of Oahu and have run into some interesting problems with the AHJ's. The biggest issue is nobody is allowing line side taps on the island, so most of are larger systems are requiring service upgrades, this also requires replacing the feeder of course and plenty of trenching which adds so much time and cost to the whole process.. Now I know Bill Brooks was on island recently and and this seems to have done no good. I was wondering if anybody can shed some light on this issue and the reasons why they would not allow this code compliant option. This is allowed on commercial systems here just not residential to be clear. And If your out there Bill, do you have any suggestions on how to approach this matter with the local inspectors??? Mahalo, -- * James B Rudolph* *Heleakala Solar* * * *Director of Construction* *NABCEP Certified PV Installer* * * * * * *Don't get me wrong: I love nuclear energy! It's just that I prefer fusion to fission. And it just so happens that there's an enormous fusion reactor safely banked a few million miles from us. It delivers more than we could ever use in just about 8 minutes. And it's wireless! - William McDonough ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings:
Re: [RE-wrenches] Combining Solectria PVI 2500 with SB3000
This is fine; your PVI2500 is rated for 10.4A, while the SB3000 is 12.5A. You can put up to 24A rated current through your 30A fuses. Though the disconnect isn't technically a service disconnect, I'd recommend using a 60A rated (fused at 30A) disconnect per 230.79(D). You would run a neutral to your combining panel and I'd recommend a PV SYSTEM ONLY; NO LOAD CIRCUITS TO BE ADDED placard on that. Otherwise that'll be an electrician's first choice when wiring up the new 40A hot tub. I think something like the Cutler-Hammer BR24L70RP panel may be a good fit, and it would replace your fused disconnect. It only has space for two 2P breakers (no main). On 2012/4/19 12:29, Dave Palumbo wrote: Wrenches, We have an installation in place since 2008 working well with a Solectria PVI 2500 feeding a supply side grid connection. Homeowner wants us to double the system size now. I can buy a SB3000 inverter for $ 300 less than the Solectria PVI 2500 (with upcharge for 10 yr warranty) and I’m inclined to go with the Sunny Boy. We would add an Inverter 240Vac combiner load center before our 30A Fused Disconnect. I would think that it would be OK to combine the 240vac outputs of different inverter manufacturers and sell into the grid but never having done this I wanted to run it by you folks. The SMA phone tech didn’t seem to be the most experienced person and after I spoke with him for a minute I had him saying that it should work fine. But wanted to check with more experienced people. One wrinkle is that the Solectria does not use a Neutral, but the Sunny Boy does. Again, I don’t think that this will any problem. David Palumbo Independent Power LLC 462 Solar Way Drive Hyde Park, VT 05655** */www.independentpowerllc.com /* NABCEP Certified PV Installer Vermont Solar Partner 24 Years Experience, (802) 888-7194 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Module Eff
You can calculate this yourself pretty easily for the many modules that don't explicitly state their efficiency (or for those that just state the cell efficiency). Get the total *metric* length and width of the module from the cut sheet. Multiply to get your area in square meters. 235W / (1.638m x 0.982m) = 146.1 W/m2. Since efficiency is calculated at STC, 1000 W/m2, 146.1W/m2 = 14.61% efficiency. Happy weekend all. DKC On 2012/4/6 15:06, All Solar, Inc. wrote: All, Got it now! My old spec sheets had no eff. listed Jeremy All Solar, Inc. Jeremy and Amy Rodriguez 1463 M St Penrose, CO 81240 www.asolarelectric.com http://www.asolarelectric.com Phone 719-372-3808 Fax 719-372-3804 Email allso...@scswifi.net mailto:allso...@scswifi.net Email allso...@live.com mailto:allso...@live.com ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] solar accumulation panel
Nick, I don't see that name (or an alternate term) in the report on proposals (do a search for 120% or 4-375a). http://www.nfpa.org/Assets/files/AboutTheCodes/70/70_A2013_NEC-P04_ROPballot.pdf On 2012/3/9 16:45, Nick Vida wrote: Hello, I was wondering if any of you wise wrenches know if 'solar accumulation panel' is still the name proposed to be used in the NEC. I think I remember Bill Brooks mentioning that they couldn't get it in for 2011, but that it will probably be good for 2014. I was wondering because here in Los Angeles they are revising the standard plan and they have an unusualname for the device, so as it is still a draft, I would us like to align with the future, if at all possible. Thanks wrenches! Nick Vida ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Need info resource re wind hail damage
Allen, UL 1703 simulates a 1 hailstone @ 50mph by dropping a 1.18lb 2 diameter steel ball 51 onto the glass at any point considered most vulnerable. IEC 61215 actually uses a 1 ice ball (what a weird thing to use when simulating hail, right?) and shoots it at 11 points on the module at 50mph. The test procedure is a bit vague as it seems a manufacturer can choose for a tougher hail test-- up to a 3 hail stone at 88 mph to better reflect the terminal velocity of larger hail. I've never seen a spec sheet indicating that a manufacturer has undergone testing for 1 hail, though YouTube shows a Conergy module taking a 75mph 2 hailstone. http://www.youtube.com/watch?v=8ztdmkcd6lE http://www.youtube.com/watch?v=aI6K3xlgYoY These impacts are all perpendicular to the module. So any module that's listed to either of these standards (preferably both) can take at least a 1 hailstone, and likely larger though that's not part of the test. A higher-sloped module should be able to withstand slightly greater impacts as the impact wouldn't be perpendicular, but of course higher slopes will increase the client's concerns about wind. Speaking of: IEC tests a 50psf uplift (wind) and a 113 psf downforce (snow). Unless you're on a roof corner or eave in a high-wind area, you won't reach 50 psf. You could offer that a structural PE could stamp your drawings to verify this, and their insurance would cover any issue with wind damage. More info on these tests was on the list back around October 7-10, subject line Module Load Rating. I understand William's point, but since you're answering a direct question from a customer with facts and testing information from international standards, I'd say you're in the clear. Saying I've never had a module fly off the roof or get damaged by hail and it's a silly thing to worry about or sending an email each week in continued attempts to convince the husband would obviously not be the way to go. Of course, once you answer these questions, he'll then point out that all that metal on the roof will attract lightning from a 500 mile radius and he will ask where in the international standards PV is tested to withstand direct strikes... and then note that no standard certifies PV to withstand the daily 30-year onslaught of morning dew. Good thing you're in the desert. Hope this helps. DKC On 2012/3/8 23:13, Allan Sindelar wrote: Fellow Wrenches, We have an engineer-type whose wife wants badly to do a PV system, but he puts up barriers. In her words: Well, I don't know how long ago it was, surely old technology by now, but some experimental solar panels at Sandia Labs were shattered by hail and it caused a big controversy. My husband says it turned him off solar.It comes up every time I talk to him. Either he is complaining about the wind or the hail or whatever. I get to respond to this, and am seeking specific assistance: Can anyone send me a link to any formal standards, or reports of aggregated field experiences, indicating that wind and hail (not to leave out whatever) are not issues of concern when PV modules are installed correctly? Anything that came from Sandia Labs would be ideal, but it just has to be reputable enough to satisfy a grouchy retired national lab engineer. Web links, reports, product warranties, etc. - all good. Thank you in advance. Allan -- *Allan Sindelar* _Allan@positiveenergysolar.com_ mailto:al...@positiveenergysolar.com NABCEP Certified Photovoltaic Installer NABCEP Certified Technical Sales Professional New Mexico EE98J Journeyman Electrician *Positive Energy, Inc.* 3201 Calle Marie Santa Fe, New Mexico 87507 *505 424-1112* _www.positiveenergysolar.com_ http://www.positiveenergysolar.com/ * * ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] AUO ac moudles
As Abraham Lincoln famously said, I'll give it my best shot, but I'm no Bill Brooks. A DC ground fault is not impossible on an AC module but it's not the issue that it is on large DC systems where numerous high-voltage parallel strings can feed an array fault. When the unit is listed it's tested to withstand the maximum DC current available from its power source- that 250W-ish module. I don't see any issue with the NEC intent relating to DC GFDI when 690.6(D) explicitly states that AC modules shall be permitted to use a single detection device to detect only ac ground faults, and disable the array by removing ac power. (NEC 2008) That being said, I can't quite tell what's going on with the AC wire on that datasheet-- it seems that those wires would be dangling (even if installed end-to-end rather than side-by-side), so I'd recommend supporting those above the roof like you're used to doing. On 2012/2/23 12:08, Bill Hoffer wrote: Todd I have been researching micro inverters and AC modules for another client and have been wondering about GFDI requirements on the DC side, according to the NEC code an AC module may be permitted to have GFDI on the AC side only, apparently because it has been tested as a complete , environmentally protected unit . This is a no brainer with units like the Exceltech AC module which is integrated into the junction box of the module, but the AUO brand seems to be also listed as an AC module which has normal MC4 connectors between the module and inverter (kinda jerry rigged in my opinion). This makes me think that there is a potential for a DC ground fault, but because of the AC Module listing on this unit , as far as I can tell, does not have an integrated GFDI. My main concern is safety and liability, but there seems to be a real gaggle of wiring under the module w/o a good way to protect it from damage on the roof. There could be a situation of a DC ground fault causing a fire on a residence that would result in some legal finger pointing, which I would not like to have pointed back to me as an installer! As far as how well this AC module performs, I have no field experience. There seems to be a real disconnect between UL 1741 requirements and what the testing authorities are calling AC modules and the the intent of the NEC GFDI requirements on the DC side. I am concerned that the final interpretation will fall on the local inspector and cause a lot of grief for us installers. IMHO installers need to beware of this hassle potential and at a minimum insure that their local inspector accepts it before installing and make sure your insurance is up to date! It would be interesting to hear from Bill Brooks on this one! Bill Bill Hoffer PE NABCEP Certified Solar PV Installer™ Sunergy Engineering Services PLLC 2504 Columbia Ave NW East Wenatchee WA 98802-3941 suneng...@gmail.com mailto:suneng...@gmail.com Cell:(509)679-6165 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] AL vs CU
If you're running them on a rooftop (i.e. not buried), expansion/contraction is a bigger issue with aluminum than copper-- so plan for that as best you can, like with loops in pull boxes and sweeps rather than LBs. On 2012/2/13 13:39, Exeltech wrote: AL advantage: Weight (especially in long overhead runs). Theft factor (less attractive than CU to thieves at the moment). CU advantage: Smaller conductors for a given current. CU-friendly lugs are readily found on the shelf. Ease of attachment to hardware. Less brittle/more flexible than AL. Commonly available in a variety of gauges. Common to both: Both metals corrode if improperly protected. AL/CU recognized splice blocks alleviate dissimilar metals issues. Likely there are many more. There's a wealth of experience in this group. Dan --- On *Mon, 2/13/12, James Rudolph /jamesrudolp...@gmail.com/* wrote: From: James Rudolph jamesrudolp...@gmail.com Subject: [RE-wrenches] AL vs CU To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Monday, February 13, 2012, 10:35 AM Gurus, Other than the cost and increased labor what else could be a factor in determining whether or not to use copper or aluminum in long output circuits? -- * James B Rudolph NABCEP Certified PV Installer California Certified Journeyman Electrician *Don't get me wrong: I love nuclear energy! It's just that I prefer fusion to fission. And it just so happens that there's an enormous fusion reactor safely banked a few million miles from us. It delivers more than we could ever use in just about 8 minutes. And it's wireless! - William McDonough ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Tax Credit for New Construction?
The credit still applies. Some things to note are that the placed in service date is when your customer actually moved in. So if he waited until the new year to move for property tax reasons (?) he can't claim the 30% credit until the 2012 tax year. Also, the credit only applies to new equipment (just so you can't move your system from one house to the next and claim 30% each year, I guess). Finally, you can't do something crazy like claim the $1.5M house is the mounting structure for the 5kW PV system and get a $460k rebate from the IRS. Note that I'm basing this off the SEIA tax credit guide v1.2 from 2006 (back when it was publicly available), so your mileage may vary. Not actually a tax expert, Dave On 2012/2/7 16:31, Ray Walters wrote: Hi All; I just had a customer ask if he could take the federal solar credit for his PV system on his newly built off grid home. I always thought you could, but the wording on the IRS form sounded a bit like you couldn't take it for new construction. What's the group's opinion on this? Ray Walters ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
