[RE-wrenches] Ferrites for EMP/solar flare protection?
Wrenches, One of our grid-tied solar + storage customers with a SolarEdge StorEdge / LG Chem RESU10H system found some information online about protecting solar systems from an EMP: Solar Power Ferrite Bundle - Practical Disaster Preparedness for the Family (disasterpreparer.com)<https://disasterpreparer.com/product/solar-ferrite-bundle/> Our customer is asking for our recommendation on this. We have used Ferrites for filtering out inverter noise but I'm not familiar with the idea of using them for protection from EMPs. Does anyone on this group specify or recommend these sorts of products for that purpose? Is there any historical evidence of EMPs being a threat to solar systems? Thanks, -Hans Hans Frederickson, President [Cascadia Solar] www.cascadiasolar.com ><http://cascadiasolar.com/> ___ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org 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 There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
Re: [RE-wrenches] Grounding - Exposed Metal Part
Mark, If you look at NEC 250.104(C), you'll find that you have to bond structural metal that is likely to become energized. The phrase likely to become energized is not defined, and is up to the AHJ. I would guess most AHJ's would consider the second metal plate to already be bonded since it is electrically continuous with the first metal plate, because they're touching. I also doubt they would consider it likely to become energized because you bonded the first metal plate. Just my opinion. -Hans -Original Message- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Mark Frye Sent: Wednesday, July 25, 2012 7:29 PM To: RE-wrenches Subject: [RE-wrenches] Grounding - Exposed Metal Part A bare metal plate is connected to a conduit which serves as an equipment ground. The plate is grounded and needs to be grounded because it could become energized both by being contact with the conduit which could become energized and also by coming into contact with the current carrying conductors themselves. A second bare metal plate touches the first plate but could not come into contact with the current carrying conductors. True or false, the second plate does not have to be grounded (bonded to the first plate) because the first plate is already grounded and therefore could not cause the second plate to become energized? Any Code references to support your opinion? P.S. I believe: false, the second plate must be bonded to the first plate because it may become energized by the first plate regardless of whether or not the first plate is actually grounded, but I can't find references in the Code to support this. 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] two buildings one grid connectioon
I have done this with two houses, each having its own utility meter and service. The AHJ approved it because all of the solar components were exterior to the host building, we had DC and AC disconnects at the host building, and we had engraved placards at both services identifying the location of everything and the point of interconnection. I don't believe there is anything in the NEC that would disallow it, but local codes or utility requirements might be a problem. -Hans On Jun 15, 2012, at 5:49 PM, Allen Frishman amfr...@aeonsolar.com wrote: Hey Wrenchers, I have been asked to participate in a feasibility study for a ~300KW Grid Tied solar system in NYC. There are two adjacent detached buildings, one has great unshaded space with very little usage and the other has no available roof space with high annual usage. The separate owners of the two buildings want to work out a deal to install the array on the good space roof and grid connect to the other building. Is there anything in the NEC that will not allow this? I know there was a topic discussed last year Two Buildings, two services, one roof but that project was never installed and therefore no conclusion made. Any and all feedback is appreciated. Thank you Al Frishman AeonSolar (917) 699-6641 - cell (888) 460-2867 www.aeonsolar.com Al Frishman AeonSolar (917) 699-6641 - cell (888) 460-2867 www.aeonsolar.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] dial-down breakers and buss rating
Kirk, Well, the NEC just refers to the sum of the ampere ratings of the overcurrent devices, which doesn't leave much wiggle room for adjusting an 800A rated breaker downward. I would check with your inspector ahead of time if you want to try this approach. -Hans From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Kirk Herander Sent: Friday, March 30, 2012 12:44 PM To: RE-wrenches Subject: [RE-wrenches] dial-down breakers and buss rating Hello, Here's one I haven't come across before. I am about to start a 110kw system. This is a 480/277 three phase ac output. The calcs tell me I need a 200 amp breaker(after rounding up from the actual breaker calc of 180.5 amps) feeding a 800 amp panelboard which is also fed by a 800 amp utility main breaker. Following the 120% rule no more than 960 amps can be put on the buss. But the source input will be 1000 amps from grid and pv combined. However, the 800 amp breaker can be current-limited down lower (in this case at least to 760 amps) by a manual dial with calibration markings on its face. So I would think a reasonable AHJ would accept this as code-compliant. The only other alternative is to replace the main with a 700 amp (no fixed-amperage breaker is made between 700 and 800 amps), which for load reasons the owner doesn't want to do. Thanks for your comments. A pesky inspector might say what's to prevent some yahoo from turning the breaker back up to 800 amps once I leave, for instance. Kirk Herander VT Solar, LLC dba Vermont Solar Engineering NABCEPTM 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
Re: [RE-wrenches] Expansion on conduits on commercial roof tops!
You just need to keep your strut straps loose enough that the conduit will slip as it expands and contracts. Sometimes you'll need to use the next size bigger strap from the conduit you're using. Then make sure you strap the barrel of the expansion coupling tight, and remember to leave enough slack wire in your boxes and conduit bodies to allow for conduit expansion to pull on the wire a bit without stressing wire terminations. That's it. The Carlon guide for installing their PVC parts covers this stuff pretty well: http://www.carlon.com/Installation_Training/IT-ISEXPJT.pdf Regards, -Hans From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of James Rudolph Sent: Friday, December 23, 2011 5:53 AM To: RE-wrenches Subject: Re: [RE-wrenches] Expansion on conduits on commercial roof tops! Thanks fellas, I guess I was not clear. We are using RMC or IMC on all of are roof top runs with the appropriate expansion fittings. I am trying to figure out how to deal with the movement of the conduits at the bases where we strap it down to the base( a curb with a small peice of shallow b-line placed on it (4') ). On Thu, Dec 22, 2011 at 12:06 PM, Jason Szumlanski ja...@fafcosolar.com wrote: PVC conduit? Search for Carlon PVC Expansion Fittings. They publish a good PDF that shows when expansion fittings are required and how to install them properly. Jason Szumlanski Fafco Solar From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of James Rudolph Sent: Thursday, December 22, 2011 9:39 AM To: RE-wrenches Subject: [RE-wrenches] Expansion on conduits on commercial roof tops! Howdy Wrenches, I was wondering how everybody is dealing with expanding conduits on roof tops? Do we have an accepted best practice on this?. What I am really looking for is a way to starp long conduit runs on commercial rooftops in direct sun that allow movement and expanision joints to do thier job. Mahalo in advance! James B Rudolph NABCEP Certified PV 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 -- James B Rudolph NABCEP Certified PV 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
Re: [RE-wrenches] Expansion on conduits on commercial roof tops!
We've covered this a few times before. Here's a recap of my previous comments: 1) I use EMT on rooftops, not PVC. PVC conduit just moves too much to be safe for a lot of expansion/contraction long-term. However, if you're in Hawaii, you might have a different set of issues. EMT could rust out quickly and perhaps your temperature swings aren't as great. 2) If you do decide to go with steel conduit, it moves much less than PVC, and you can get a longer run in before you need an expansion coupling. To calculate expansion, see the FPN for NEC 300.7(B). You take the values in Table 352.44 and multiply by 0.2 for steel conduit. 3) Pay attention to how you strap your conduit. The straps adjacent to an expansion coupling need to be loose enough to allow the conduit to slip as it expands/contracts. 4) OZ-Gedney makes a UL-listed expansion coupling for EMT, the TX series. Regards, -Hans From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of James Rudolph Sent: Thursday, December 22, 2011 6:39 AM To: RE-wrenches Subject: [RE-wrenches] Expansion on conduits on commercial roof tops! Howdy Wrenches, I was wondering how everybody is dealing with expanding conduits on roof tops? Do we have an accepted best practice on this?. What I am really looking for is a way to starp long conduit runs on commercial rooftops in direct sun that allow movement and expanision joints to do thier job. Mahalo in advance! James B Rudolph NABCEP Certified PV 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
Re: [RE-wrenches] Grouping of Service Disconnects
Jason, I agree that the inspector is wrong. I see two options: 1) Appeal the inspectors ruling with his supervisor(s). 2) Cut in a little flush mount service disconnect adjacent to the main service panel. You could use a 2-space flush-mount panel like Cutler Hammer CH2L125FP. This is rated for service entrance use, but does not include a visible break disconnect (just a breaker), so depending on your utility's requirements, it might need to be redundant to your fused disconnect outside. Regards, -Hans From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Jason Szumlanski Sent: Thursday, December 08, 2011 5:22 AM To: RE-wrenches Subject: [RE-wrenches] Grouping of Service Disconnects I know this has been discussed ad nauseum, but. I have a supply side tap with a fusible disconnect located next to the meter outside. The tap is in the main distribution panel which is back to back with the meter inside a finished garage. There is a 200A main breaker in the MDP. The inspector is insisting that the solar AC disconnect (fusible disconnect) be located inside the garage next to the MDP. He is saying that service disconnecting means must be grouped. The inspector acknowledges that the PV system is considered a separate source, not necessarily a separate service, but also insists that Section 230 applies. I pointed out that section 230.72(A) and 230.71(A) apply to grouping of service disconnects for the SAME service, not grouping of all disconnects for multiple services. I noted that the location required in 230.70(A)(1) allows for the disconnect to be outside the building. There is no explicit requirement for disconnects of separate services to be co-located (grouped). I also pointed out 690.56(B) which implies that the PV system disconnect can be located elsewhere if a plaque or directory is supplied. I thought this was case closed, but he is still not seeing it my way. I realize that the AHJ could theoretically make the determination that the disconnect be located inside, but that is not the case he is making. He is stuck on the grouping aspect. I have provided Enphase's white paper on disconnecting means and the excellent IAEI articles on the subject. I think they are interpreting the word each in 230.71(A) to mean all. I'm not sure. There is no way that the homeowner will allow a surface mounted fusible disconnect next to his flush mounted MDP in the garage. The next best alternative to comply with the inspector is expensive and time consuming, and a load side connection is out of the question. Not happy right now. 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
Re: [RE-wrenches] Bifacial modules
For the Sanyo and Silicon Energy modules I've worked with, it is a very small amount of light that actually passes through in the gaps between the cells. You could do a simple ratio calculation by measuring the area of the gaps and the area of the cells. Just guessing, I would say about 3-4%, if that. I wouldn't count on getting much daylight under the array except for what bounces in from underneath. Depending on the height of the array and reflectivity of nearby surfaces, the reflected light under the array can be significant. Hope this helps. -Hans From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Keith Cronin Sent: Tuesday, November 01, 2011 1:04 PM To: RE-Wrenches Subject: [RE-wrenches] Bifacial modules Hi Was wondering if any of you have installed bifacial modules and know what the % of light that comes through to a surface below the modules? Looking for a canopy type of installation/ application and wondered if you have any #'s? Thank you~ Aloha, Keith ___ 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] High PSF Mods?
I second the opinion on Silicon Energy modules. Our crew doesn't hesitate to walk or climb directly on the modules when they need to. They also have good impact resistance. We installed a 75kW system on a flat roof at a middle school and walking around on the roof, you would guess that it had been raining rocks. No broken modules yet, but I'd still like to get a hold of those little punks. ;) -Hans _ From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Bill Hoffer Sent: Tuesday, September 27, 2011 4:02 PM To: Jeff Clearwater; RE-wrenches Subject: Re: [RE-wrenches] High PSF Mods? Jeff Silicon Energy has a 125 PSF rated module which slightly exceeds 5400 Pa ( 113 PSF). I would guess that it can actually handle a lot more than that. Good looking module with a cascading mounting system included that also makes a clean raceway for the wiring for a very clean install. Frameless on two edges to allow rain snow and dust tor easily run off. It is a bit spendy, but I would guess that it is one of the toughest modules in the market. On Tue, Sep 27, 2011 at 3:18 PM, Jeff Clearwater je...@villagepower.com wrote: Hello Again Wise and Knowledgeable, What's folks favorite modules for high psf ratings? I know RECS have high ratings. Others? Thanks! Jeff -- Jeff Clearwater Village Power Design Renewable Energy Consultant 32 Years in all Aspects of Renewables www.villagepower.com skype: jclearwater 413-559-9763 ~ ___ 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 -- Bill Hoffer PE NABCEP Certified Solar PV InstallerT Sunergy Engineering Services PLLC 2504 Columbia Ave NW East Wenatchee WA 98802-3941 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
Re: [RE-wrenches] 1987 NEC
Kent, I'm not a geezer yet, but thanks to my dad I do have a copy of the 1987 NEC. 690-5 (Ground Fault Detection and Interruption) was added in the 1990 NEC. There is no 690-5 or mention of ground fault detection/interruption in the 1987 NEC. In the 1990 NEC, section 690-5 is very small compared to 690.5 in the 2011 NEC. Here's the complete text from 1990: 690-5. Ground Fault Detection and Interruption. Roof-mounted photovoltaic arrays located on dwellings shall be provided with ground-fault protection to reduce fire hazard. The ground-fault protection circuit shall be capable of detecting a ground fault, interrupting the fault path, and disabling the array. The handbook for 1990 goes on to say that the gfp device must: 1) detect the ground fault 2) open the grounded conductor to interrupt the ground fault 3) open the ungrounded conductors and short the photoltaic array source to disable it For some reason, I've never heard of item #3, specifically the part about shorting the array. Can anyone shed light on this? Regards, -Hans _ From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Kent Osterberg Sent: Monday, July 18, 2011 10:07 PM To: g...@icarussolarservices.com; RE-wrenches Subject: Re: [RE-wrenches] 1987 NEC Gary, No one else has come up with a 1987 NEC. If you can get a copy of 1987 section 690.5 (I think it was 690-5 back then), I'd appreciate it. Kent Osterberg Blue Mountain Solar Gary Willett wrote: Kent: I am a member of the International Association of Electrical Inspectors (IAEI), and they're headquartered here in the Dallas area. If you aren't successful getting the info from a Wrench with the 1987 code book, let me know and I am sure I can request a FAXed copy of 1987 section 690.5. Regards, Gary Willett, PE g...@icarussolarservices.com On 7/15/2011 4:30 PM, Kent Osterberg wrote: I'm looking for the text of 1987 NEC 690.5 to compare with 2011 version. If any of you geezers have kept copies that old, please contact me off list. Thanks. Kent Osterberg Blue Mountain 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 ___ 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] 1987 NEC
David, Thanks for the interesting history on GFPDs. My copy of the 1987 NEC does not have 690-5, and it's not missing any pages. Either my code book is an incomplete printing or perhaps John Wiles was referring to a 1987 proposal that didn't make it into the code until the 1990 NEC. Regards, -Hans _ From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of David Brearley Sent: Tuesday, July 19, 2011 12:57 PM To: RE-wrenches Subject: Re: [RE-wrenches] 1987 NEC Hans, John Wiles described the evolution of this standard for a Home Power article that we referenced later in a SolarPro on PV System Ground Faults: http://solarprofessional.com/article/?file=SP2_5_pg60_Mync As described by John Wiles, program manager for the Institute for the Energy and the Environment, in the February/ March 2008 Home Power article Ground-Fault Protection Is Expanding, Article 690.5 was added to the NEC in 1987. One of Wiles' first projects in the PV industry was to develop prototype hardware to meet the new Code requirement. The basic concept (of the original GFPD prototype), writes Wiles, was to insert a 0.5- or 1-amp circuit breaker in the dc system-bonding conductor. This small circuit breaker senses any current between the grounded current-carrying conductor and the grounding system, tripping if current exceeds the 0.5 A or 1 A rating. By mechanically linking this smaller breaker to larger capacity breakers that are installed inline with the ungrounded current-carrying array conductors, it is possible to detect, interrupt and indicate that a ground fault has occurred, and to disconnect the fault. These early GFPDs were manufactured for 48 V or lower PV systems. According to Wiles, As higher voltage, utility-interactive PV inverters became available in the late 1990s, using a 0.5- or 1-amp fuse as the sensing element and the inverter's control electronics to monitor the fuse was more cost effective. While the sensing equipment may have changed, in general the role of the modern GFPD remains the same as it was in 1987: 1. Detect ground faults in PV arrays. 2. Interrupt the fault current. 3. Indicate that a ground fault has occurred. 4. Disconnect the faulted part of the array. These four GFPD requirements for grounded PV arrays are spelled out in NEC 690.5(A) and 690.5(B). The former requires ground-fault detection and interruption (GFDI), which includes the provision to indicate the presence of a ground fault. The latter requires that faulted circuits be isolated either by disconnecting the ungrounded conductors of the faulted circuit or by shutting down power to the output power circuits of the inverter or charge controller. A final GFPD requirement is found in Article 960.5(C), which calls for a visible warning in the proximity of the ground-fault indicator. The warning could be an LED, an LCD or both. In general, the manufacturer provides this electric shock hazard warning as part of the listed grid-tied inverter or charge controller. However, where a PV system includes batteries, the installer must apply a duplicate warning label near the batteries, stating: WARNING ELECTRIC SHOCK HAZARD IF A GROUND FAULT IS INDICATED, NORMALLY GROUNDED CONDUCTORS MAY BE UNGROUNDED AND ENERGIZED One change in the GFPD requirements introduced in 1987 is that it is no longer necessary to short-circuit, or crowbar, the PV array in the event of a ground fault. This added step had the effect of reducing the PV array voltage to zero, minimizing shock hazard. The requirement was dropped in a subsequent Code cycle, as leaving the array in a short-circuited condition created several other issues. If you're a Home Power subscriber, you can access the original article in the HP archives. If not, it is summarized above. Best, David Brearley, Senior Technical Editor SolarPro magazine NABCEP Certified PV Installer T david.brear...@solarprofessional.com Direct: 541.261.6545 On 7/19/11 2:19 PM, Hans Frederickson h...@fredelectric.com wrote: Kent, I'm not a geezer yet, but thanks to my dad I do have a copy of the 1987 NEC. 690-5 (Ground Fault Detection and Interruption) was added in the 1990 NEC. There is no 690-5 or mention of ground fault detection/interruption in the 1987 NEC. In the 1990 NEC, section 690-5 is very small compared to 690.5 in the 2011 NEC. Here's the complete text from 1990: 690-5. Ground Fault Detection and Interruption. Roof-mounted photovoltaic arrays located on dwellings shall be provided with ground-fault protection to reduce fire hazard. The ground-fault protection circuit shall be capable of detecting a ground fault, interrupting the fault path, and disabling the array. The handbook for 1990 goes on to say that the gfp device must: 1) detect the ground fault 2) open the grounded conductor to interrupt the ground fault 3) open the ungrounded conductors and short the photoltaic array source to disable it For some reason, I've
Re: [RE-wrenches] Fwd: out of business
Since they're doubling up on PV technology, I thought it would be funny to suggest they have a VAWT on the pole between the crystalline PV and the HAWT. Turns out they've already thought of this! Vertical axis Wind Turbine: VAWT currently in research and development. This four source version of the PPP is only recommended for ideal lower wind locations. -Hans From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Jason Szumlanski Sent: Wednesday, May 18, 2011 4:24 AM To: RE-wrenches Subject: Re: [RE-wrenches] Fwd: out of business They should just make the turbine blades out of PV mods and kill two birds with one stone. But they'd want to use bifacial mods to capture the reflected light off the pole. My favorite is the photo gallery with superimposed images of the product in various settings. Jason Szumlanski Fafco Solar Original Message Check this out http://thepersonalpowerplant.com/ They even show the shadow from the pole across the top module -- and the modules on the bottom facing every which way, just in case the sun moves around to the north I guess. We might as well all go home now -- they're going to put us all out of business anyway. Russell Mueller Positive Energy ___ 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] Single phase to three phase interconnect
Eric, For a 6kW system on a reasonable size commercial service, it shouldn't be a problem to stack your 2 inverters on one or two legs of the 3-phase service. Loads are never perfectly balanced, so synchronous generators don't need to be either, up to a point. Ask the utility if you can feed the 6kW in on one leg. They'll look at their transformer for the service in question and make a decision. If they let you do it, just try to feed in on the most heavily loaded leg of the 3-phase service. Regards, -Hans From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Eric Thomas Sent: Monday, April 25, 2011 11:01 AM To: re-wrenches@lists.re-wrenches.org Subject: [RE-wrenches] Single phase to three phase interconnect While commercial solar work is newer to me, im surprised this hasn't been addressed very much in our forum: Interconnecting single phase inverters to three phase services. We are laying out a 6kW system using Silicon Energy Cascade modules and Aurora PVI inverters (either 2 or 3 PVI 3.0's). The challenge is finding a way to easily tie two of these inverters into the existing 3phase service. I've been reading up on Sunny Boys tech notes and on this forum about imbalance and such, but im still not comfortable enough with tie in. Due to the string configuration options, I can add a third inverter and use a three phase subpanel to aggregate the inverters then tie them in. But adding a third inverter seems like a goofy solution. In looking at available equipment, transformers, phase converters etc, I can't seem to find the right fit. Any ideas? This system does not have a three phase inverter option due to Made in WA req's. Thanks! Eric Thomas Solar Epiphany 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
Re: [RE-wrenches] Two Buildings, Two Services, One Roof
I don't think you'll find anything in the NEC to prohibit that. NEC 250.52(A)(1) requires you to bond a metal underground water pipe (if it exists) to the grounding electrode system. In older neighborhoods with metal water pipes, the grounding electrode systems for all the houses are bonded together (through the metal water pipe). The only potential problem I know of with the GECs for multiple services bonded together in this way is that if a bad connection develops on the incoming grounded service conductor (neutral), unbalanced (neutral) current can start flowing through the pipes to neighboring services and back to the transformer through their neutral wires. Bottom line: call your AHJ, tell them what you plan to do, and ask them if they have a problem with it. You should also check with the utility. Regards, -Hans _ From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Mark Frye Sent: Monday, April 18, 2011 2:05 PM To: 'RE-wrenches' Subject: Re: [RE-wrenches] Two Buildings, Two Services, One Roof Or another way to illustrate this problem: There is nothing in the Code that would stop me from hauling out the old #6 and bonding my GEC to my next door neighbors GEC, if I wanted to? Mark Frye Berkeley Solar Electric Systems 303 Redbud Way Nevada City, CA 95959 (530) 401-8024 http://www.berkeleysolar.com/ www.berkeleysolar.com _ From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Mark Frye Sent: Monday, April 18, 2011 2:00 PM To: 'RE-wrenches' Subject: Re: [RE-wrenches] Two Buildings, Two Services, One Roof Dana, Exactly, why not? I can't find anything in the Code that says 'Thou shalt not make a connection between the grounding system of two seperate services located on two seperate buildings. But re your example in this case the PV for both building will be located on only one of the two. Mark Frye Berkeley Solar Electric Systems 303 Redbud Way Nevada City, CA 95959 (530) 401-8024 http://www.berkeleysolar.com/ www.berkeleysolar.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
Re: [RE-wrenches] PVC running through the house
690.31(E), requiring metallic raceways or enclosures for DC circuits inside the building was introduced in the 2005 NEC. Depending on when the 2005 NEC was adopted by your local authority, it may or may not have been required at the time of the installation. -Hans _ From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Keith Cronin Sent: Thursday, April 07, 2011 3:05 PM To: RE-Wrenches Subject: [RE-wrenches] PVC running through the house Hi folks Was wondering- does anyone know back in 2005, if it was permissible to run DC conductors from the roof, through the home to the inverter location, inside the house, per the NEC? Thanks Keith Cronin ___ 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] Backfeeding GFP devices
Wrenches, I'm looking at a fair number of school projects these days. So far, every school service I've looked at has a ground fault protection device at the main service disconnect. I just completed a 75kW school project where we did a line side tap. The panel gear was old, maybe 1960s Federal Pacific. Lately, I've been looking at schools with newer gear. In SolarPro 2.4, the Can We Land? article mentions the possibility of getting a GFP device that is capable of being backfed. Has anyone seen or used such a device in conjunction with a big service? Are there any known manufacturers of GFP devices that are listed for backfeeding? For a current project, I would like to backfeed a GFP device that is controlling a 3000A switch on a 480V service. Also, because I'm a curious person, I'm wondering if anyone has ever backfed a GFP device not listed for that use, perhaps without realizing it, and what the result was? Thanks, -Hans Hans Frederickson Estimator / Project Manager Frederickson Electric, Inc. (360) 385-1395 ___ 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] Sharp Warranty in Marine Environment
I haven't heard that about the modules, but this was true for the racking a couple years ago when we installed an SRS/OnEnergy system. IIRC, bodies of salt water needed to be at least 2 miles away. Because the SRS racking is steel, it is more susceptible to corrosion from salt air. My understanding is that Sharp has recently discontinued the SRS/OnEnergy system and will be introducing something new this year. Regards, -Hans -Original Message- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of August Goers Sent: Tuesday, January 18, 2011 8:32 AM To: RE-wrenches Subject: [RE-wrenches] Sharp Warranty in Marine Environment Hi Wrenches, I recently heard a rumor that Sharp modules may not be warranted in a marine environment. This could be completely false but I thought I would reach out and see if anyone on the list has any experience in this area. Best, August ___ 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] The perfect solar ready roof
Kris has a good idea. Installing 2x backer blocks on the I-joists will not only give you more depth for your lag screws, but it will strengthen the roof framing as well. Also, as Kris recommends, check with the manufacturer for nailing patterns, etc. I was dealing with some BCI joists this past summer and I was pleased that Boise Cascade has structural engineers on staff that are eager to help, and can email you approved drawings for reinforcing the joists. -Hans _ From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Kristopher Schmid Sent: Wednesday, October 20, 2010 1:33 PM To: 'RE-wrenches' Subject: Re: [RE-wrenches] The perfect solar ready roof What about screwing in double 2x6s flush to the roof deck between the beams where your feet will attach and lag bolting into that? Definitely check with the beam manufacturer first, though. Kris Legacy Solar 864 Clam Falls Trail Frederic, WI 54837 715-653-4295 sol...@legacysolar.com www.legacysolar.com -Original Message- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Scott McCalmont Sent: Wednesday, October 20, 2010 12:00 AM To: RE-wrenches Subject: Re: [RE-wrenches] The perfect solar ready roof In general, you shouldn't drill or cut the flanges on engineered wood beams. I think that eliminates lag screws into the rafters. They probably wouldn't have the same pull-out strength as a lag screw into a conventional rafter, either. Scott On Oct 19, 2010, at 7:58 PM, Chris Daum wrote: Dear Wrenches: I have a composite (shingle) roof at hand, and the owner wants to upgrade it to a metal roof and install a 5kw+ array on it. The rafters are those (sort of) particle board I-beams covered with 1/2 plywood (and shingles). What's the best metal roofing you could suggest--and would you beef up the wood to lag into? Thanks for all your input. Chris Daum Oasis Montana Inc. 406-777-4309 406-777-0830 fax ___ 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 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
Re: [RE-wrenches] Tranformless inverter
Ryan, Yes, there are twice the number of ungrounded conductors, so twice as many fuses and switches are required. I haven't seen much in the way of combiners for ungrounded systems... A combiner for an ungrounded system has two fused ungrounded sections instead of the typical combiner of today which has fuses on the ungrounded input conductors and just a terminal block for all the grounded conductors. -Hans -Original Message- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Ryan LeBlanc Sent: Saturday, October 02, 2010 10:52 AM To: re-wrenches@lists.re-wrenches.org Subject: Re: [RE-wrenches] Tranformless inverter Bill, Specifically, the additional fusing and disconnect requirement you mentions. Is that each positive and negative PV Source and Output Circuit must have OCPD and go through switched? Twice the combiner boxes, fuses and switches? Thanks, Ryan J. LeBlanc NABCEPT Certified Solar PV Installer Cell: 707.591.1950 Direct: 707.536.9839 r...@naturalenergyworks.com http://www.NaturalEnergyWorks.com Ungrounding the array requires additional fusing and disconnects, but the most significant difference is that the module wiring and all external cable must be PV Wire/Cable. Therefore only modules with PV Wire/Cable can be used in these systems. You must confirm from the manufacturer that they have made the switch. Hopefully all manufacturers will be installing PV Wire/Cable soon so that this will not be a problem anymore. ___ 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] Ladder Hoists
Wrenches, I'm interested in hearing from those of you that use a ladder hoist to move modules from the ground to the roof. Does anyone have a product that they would recommend? Any problems? Thanks, -Hans ___ 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] PV GEC to the same point as theutilityservice GEC?
Ray and Matt, Thanks for sharing your perspective on the EGC and GEC requirements. I share Ray's distaste for creating ground loops with redundant GECs, and I'm thankful for 690.47(C)(3), particularly the last sentence: A single conductor shall be permitted to be used to perform the multiple functions of dc grounding, ac grounding, and bonding between ac and dc systems. In the draft of the 2011 NEC, there is completely new wording for 690.47(C). I find it to be more understandable than the 2008 code, and I recommend checking it out: http://www.solarabcs.com/index.php?option=com_docman http://www.solarabcs.com/index.php?option=com_docmantask=doc_downloadgid= 248Itemid=72 task=doc_downloadgid=248Itemid=72 As for 690.47(D)... I just can't stop hating this one. I was dismayed to find that it made it into the 2011 NEC without changes. Is there any purpose for 690.47(D) other than enhanced protection from direct lightning strikes? If so, and you're installing in an area where direct lightning strikes are a problem, shouldn't you be installing a proper lightning protection system per NFPA 780? As far as I can tell, the main practical consequence from implementation of 690.47(D) is that you're almost guaranteed to set up a big ground loop that will suffer induced currents from nearby lightning strikes. Please, somebody justify the existence of 690.47(D), particularly for those of us that live in areas where lightning is rare, so I can stop hating it. Regards, -Hans _ From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of R Ray Walters Sent: Monday, August 23, 2010 1:55 PM To: RE-wrenches Subject: Re: [RE-wrenches] PV GEC to the same point as theutilityservice GEC? I think the issue is that some installers are wanting the supplementary electrode for the array tied to the building grounding system in two places. I saw this in BIll Brooks seminar too, but then he said it wasn't necessary. Basically the EGC system already ties both electrodes together as required, and a 2nd conductor directly between the two electrodes can create a lightning loop. If the electrodes would be close together, you can actually drop the array electrode, and tie straight to the building electrode. But if it is on the other side of the building for instance, some have run 2 conductors, 1) the already required EGC through the AC conduit, and then 2) a separate GEC on the outside of the building that connects the electrodes a 2nd time. This would be the same logic as bonding your electrode of your house to your neighbor's house: it's not necessary ( they're already bonded through the services) and it can cause trouble, especially with lightning. Even my new ground impedance tester only works, if each grounding electrode is bonded once (and only once) to the rest of the grounding system. It's a key point of lighting protection in multiple electrode grounding systems too: never create loops in your grounding system. R. Walters r...@solarray.com Solar Engineer On Aug 23, 2010, at 9:27 AM, Matt Lafferty wrote: Hi Jason, I'm a little confused about your intention. I think you might be making this harder than it needs to be. Everything you need is right there in 2008 NEC 690.47(C). Where are you tying into the building AC distribution system? Get your GEC the same place the existing AC distribution system at your point of interconnection is bonded. If the grounding electrode conductor for the point of interconnection is building steel (like the delta-wye transformer scenario described in your original post), source your GEC there. Your AC DC grounding system(s) must be bonded together per 690.47(C)(1). For normal interactive, non-backup systems, I use a common ground bus for both AC DC (690.47(C)(5). I size it and any bonding jumpers as the smaller of #8 CU or whatever 690.47(C)(2) 690.47(C)(7) comes out to. My common GEC originates at the AC interconnection per 690.47(C)(6) 690.47(C)(8). I run the common GEC to and thru the inverter(s) and out to the array thru the raceway system. NOTE: Once you are on the array side of the inverter(s), the GEC is a DC equipment ground. I size it not smaller than #8 and large enough to carry any unintentional system currents safely to ground based on the DC configuration. This may result in multiple ground conductors running thru different conduits. Every pipe (AC DC) gets a ground wire in my systems. DC raceways should also be bonded to the GEC (meyers-hub, ground-bushing, etc.). AC raceways on the load side of an OCP do not require this provision by code, but it doesn't hurt to go ahead and do it anyway. 690.47(D) is for equipment grounding. This is a separate issue from the system GECs described in 690.47(C). I consider it to be enhanced or bonus equipment grounding. In addition to the requirements of 690.47(C), you must ALSO bond your rack to the building steel and make sure the steel is properly
Re: [RE-wrenches] Aluminum conduit LBs
Marco, I'm curious to know what you did after the hard lesson. Was it an issue of difficult/impossible installation, or an AHJ issue? It seems like the most straightforward solution in a situation like this is to replace your conduit bodies (LBs in this case) with a larger size, and then install reducers in order to leave the existing conduit runs intact. I'm looking at an upcoming installation where I would like to use 1-1/4 EMT, but will need 1-1/2 conduit bodies to be ok with wire fill. -Hans _ From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Marco Mangelsdorf Sent: Thursday, August 12, 2010 8:19 PM To: 'RE-wrenches' Subject: [RE-wrenches] Aluminum conduit LBs Anyone know where I could go to find out the max conductor sizes that threaded Al. LBs can handle? I learned the hard way that a conduit of X inches that can handle conductors of a certain size does not necessarily mean that a LB of the same diameter can handle the same size conductors. 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
[RE-wrenches] UL Listing for meter
I scanned the UL White Book and did not find a category listing for bolt-in or plug-in type watt-hour meters. There are several categories for the meter sockets. If UL hasn't taken it on, I can't imagine that anyone has paid any other NRTL to evaluate equipment that typically doesn't require a listing. I have heard of AHJ's waiving the listing requirements for equipment when no standard exists... I would suggest to the AHJ that there is no listing for watt-hour meters so this requirement is impossible to meet. Regards, -Hans -Original Message- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Peter Parrish Sent: Monday, July 26, 2010 12:19 PM To: 'RE-wrenches' Subject: [RE-wrenches] Congested Panel Problem This inspector also has a problem with the production meter we installed. He wanted to see the UL Listing on the meter. I called Austin International (our vendor) about the meter in question (Itron Centron C1S) and they said that UL doest test meters as they (normally) are not used on the customer side of the service. Is there another listing for meters that would satisfy a nit-picky inspector? To make matters worse, we now have in stock both Itron Centron C1S meters as well as Schlumberger Centron C1S meters. Did Schlumberger buy out Itron? Or vice versa? Any help on the main panel calculation and acceptable listings for meter would be greatly appreciated. Peter T. Parrish, Ph.D., President California Solar Engineering, Inc. 820 Cynthia Ave., Los Angeles, CA 90065 CA Lic. 854779, NABCEP Cert. 031806-26 peter.parr...@calsolareng.com Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885 ___ 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 anchors and proper rigging
Rebecca, Petzl makes the Navaho Bod harness with ANSI/NFPA certification. It's my understanding that this harness meets OSHA requirements. At some point I read a blurb from Petzl about how OSHA approved gear is actually self-certified by the manufacturer, which they disdain. Apparently there was no recognized testing lab for OSHA fall protection gear requirements, so they decided to use ANSI. The ANSI/NFPA certified harness is a separate part # from the regular version, so they must have made some modifications. Anyway, the harness is comfortable and I can't imagine a safety inspector having a problem with it. -Hans _ From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Rebecca Lundberg Sent: Friday, April 23, 2010 5:51 PM To: re-wrenches@lists.re-wrenches.org Subject: Re: [RE-wrenches] Roof anchors and proper rigging Finally, I use an Absorbica in conjunction with my harness and rope (again, climbing experience has helped me understand the concept of safety on a roof). And I am still looking for a comfortable OSHA-approved harness that has a front attachment point, so if anyone has suggestions I'd be interested. Rebecca Lundberg CEO/President, Powerfully Green Champlin, Minnesota ___ 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] Overcurrent Protection on a Subpanel
Since Peter is talking about a subpanel, we can assume that it is not the main service for a building/structure, and would not be subject to the disconnect requirements of NEC articles 225 and 230. In general, as long as the subpanel is in the same building or structure as the main service, it is not required to have a main breaker. There are a lot of exceptions on service entrance requirements, so it's a good idea to read through the relevant sections of articles 225 and 230 to get a handle on this. -Hans Frederickson -Original Message- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Dave Click Sent: Monday, April 05, 2010 6:07 AM To: re-wrenches@lists.re-wrenches.org Subject: Re: [RE-wrenches] Overcurrent Protection on a Subpanel One could interpret that if you have 6 or more inverter breakers getting combined in a panel, you'd want one main breaker so that you wouldn't have to turn off all ten individually to disconnect the system. Something else to ask the AHJ. Peter Parrish wrote: When we use a sub-panel to combine the output of two or more inverters, we buy the sub-panel without a main breaker. A wrench who is working with us now, recommends buying sub-panels with the main breaker, which increases cost by about 50%. Is this a code requirement? Does it depend on the distance between the sub- and main panels? - Peter Peter T. Parrish, Ph.D., President California Solar Engineering, Inc. 820 Cynthia Ave., Los Angeles, CA 90065 CA Lic. 854779, NABCEP Cert. 031806-26 peter.parr...@calsolareng.com mailto:peter.parr...@calsolareng.com Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885 ___ 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-wrenches] Split-bus panel: load/line side connection?
Wrenches, The thread about supply side overcurrent protection got me thinking about the old split-bus panels. I don't see any theoretical difference between landing on a breaker in the top section of a split-bus service panel and making a line side tap. For example, if you have a 200A split-bus service panel that allows 60A breakers in the top section, what's to stop you from installing a 60A PV source (or two, if you have room)? Thoughts? -Hans Hans Frederickson Estimator / Project Manager Frederickson Electric, Inc. (360) 385-1395 ___ 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] Supply Side Tap Overcurrent Protection
Anything less than a 100A main is a no-go a for residential service: NEC 230.79(C): For a one-family dwelling, the service disconnecting means shall have a rating of not less than 100 amperes, 3-wire. Also, I don't think any AHJ is going to accept a load calculation in lieu of proper bus sizing in the service. What's to stop the owner from adding loads later on? I agree with Eric... time for a service upgrade. -Hans Frederickson -Original Message- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Steven Lawrence Sent: Wednesday, March 31, 2010 9:54 AM To: re-wrenches@lists.re-wrenches.org Subject: Re: [RE-wrenches] Supply Side Tap Overcurrent Protection Why can't you do a line side tap and downsize the main breaker? Use a 60A main disconnect for the line side tap, and use a 60A main breaker for the service panel. That's similar to what I did except I downsized the 200A main to a 150A. This also allowed a manual interlock kit in the main service panel that can be fed from the backup load panel. Steven Lawrence __ Date: Wed, 31 Mar 2010 08:13:10 -0700 (PDT) From: Nick Soleil nicksoleilso...@yahoo.com To: RE-wrenches re-wrenches@lists.re-wrenches.org Subject: Re: [RE-wrenches] Supply Side Tap Overcurrent Protection Message-ID: 342120.66732...@web44904.mail.sp1.yahoo.com Content-Type: text/plain; charset=us-ascii Downsize the main breaker? I would if I could, but the customer only has 100 Amps now, and the solar is fed with two breakers, a 30A and a 40A. So to be under 120Amps, I would have to size the main to 50 Amps, which may be problematic. I can also do the line side tap, but had heard that a load analysis may be accepted instead. The loads of the house will never use more than 100 Amps. I am wondering if any codes or white papers detail that option. Nick Soleil Project Manager Advanced Alternative Energy Solutions, LLC PO Box 657 Petaluma, CA 94953 Cell: 707-321-2937 Office: 707-789-9537 Fax:707-769-9037 ___ 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] Supply Side Tap Overcurrent Protection
Steven, I don't think the 60A disconnect for the line-side tap would qualify as part of the required 100A rating for the residential service. You aren't using it to supply the house loads. Unless I'm missing something, your proposal limits the residential service load to only 60A. I suppose you could argue it with the AHJ... but I think you're going against the intent of the code. These sections weren't written with any consideration to grid-tied PV feed-ins. -Hans Frederickson -Original Message- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Steven Lawrence Sent: Wednesday, March 31, 2010 11:04 AM To: re-wrenches@lists.re-wrenches.org Subject: Re: [RE-wrenches] Supply Side Tap Overcurrent Protection 230.80 Where the service disconnecting means consists of more than one switch or circuit breaker, as permitted by 230.71, the combined ratings of all the switches or circuit breakers used shall not be less than the rating required by 230.79 Steven Lawrence ___ Message: 1 Date: Wed, 31 Mar 2010 10:24:17 -0700 From: Hans Frederickson h...@fredelectric.com To: 'RE-wrenches' re-wrenches@lists.re-wrenches.org Subject: Re: [RE-wrenches] Supply Side Tap Overcurrent Protection Message-ID: 71328cbb96b745889f63e627c93e8...@frederickson.local Content-Type: text/plain; charset=us-ascii Anything less than a 100A main is a no-go a for residential service: NEC 230.79(C): For a one-family dwelling, the service disconnecting means shall have a rating of not less than 100 amperes, 3-wire. Also, I don't think any AHJ is going to accept a load calculation in lieu of proper bus sizing in the service. What's to stop the owner from adding loads later on? I agree with Eric... time for a service upgrade. -Hans Frederickson -Original Message- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Steven Lawrence Sent: Wednesday, March 31, 2010 9:54 AM To: re-wrenches@lists.re-wrenches.org Subject: Re: [RE-wrenches] Supply Side Tap Overcurrent Protection Why can't you do a line side tap and downsize the main breaker? Use a 60A main disconnect for the line side tap, and use a 60A main breaker for the service panel. That's similar to what I did except I downsized the 200A main to a 150A. This also allowed a manual interlock kit in the main service panel that can be fed from the backup load panel. Steven Lawrence ___ 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
690.15, second paragraph supports Drake's method: A single disconnecting means in accordance with 690.17 shall be permitted for the combined ac output of one or more inverters or ac modules in an interactive system. 690.17 says the disconnecting means can be a switch or circuit breaker. This seems workable, with a couple caveats... The inverter manufacturer directions might specify an individual branch circuit, and you would need to use the larger size wire between the AC combiner box to the fused AC disconnect at each inverter, so you would need to choose disconnects with big enough terminals. Anyone see any other issues with this idea? -Hans From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Drake Chamberlin Sent: Wednesday, January 13, 2010 9:59 AM To: RE-wrenches Subject: Re: [RE-wrenches] Solar accumulation panel P.S. In many cases it would be necessary to use a fused AC disconnect to stay within the inverter manufacturer's specifications. At 12:53 PM 1/13/2010, you wrote: Here is a wild idea. If you look at the Enphase inverter systems, several inverters connect together in parallel before going to an overcurrent device. In all cases, the point of connection to a utility system must be at a dedicated breaker. If there were multiple string inverters that would connect to one breaker, why not just use a junction box, instead of a combiner panel? You could put in an AC disconnect for each inverter, if it didn't come with one. The wiring would need to be sized for the combined output of the multiple inverters, which in many cases wouldn't be an issue. Drake Drake Chamberlin Athens Electric OH License 44810 CO License 3773 NABCEP TM Certified PV Installer Office - 740-448-7328 Mobile - 740-856-9648 ___ 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] fancy stud sensors (was RE: Clean Energy Brands)
I saw and tried out the Milwaukee sub-scanner at the NECA show in Seattle. I haven't ever got my hands on the Bosch unit, so I can't give a comparison. The Milwaukee really needs to have a smooth surface to roll along, so I don't think it will work on comp shingle roofs. It probably would work fine on tile roofs once you remove a few tiles to get down to the roof deck. I did mention to the Milwaukee rep that there would be a significant market at their price point if they could design a tool that could see through comp shingles accurately. He hinted that they were working on it... -Hans From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of wes kennedy Sent: Tuesday, December 15, 2009 4:03 PM To: RE-wrenches Subject: Re: [RE-wrenches] Clean Energy Brands Howdy All, I have used the Bosch unit for a while, and even it is not fool proof. They also forgot to install the auto-chute deployment unit for safe landings from rooftops! Has anyone used the new whizbang sensor from Milwaukee? http://www.milwaukeetool.com/ProductDetail.aspx?ProductId=2290-21CategoryNa me=SC%3a+M12+Cordless+System Lots of technology for around $350. ___ 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] PV Powered vs SMA
Nice thread... inverter pros/cons is something I spend a fair amount of time pondering, since they are the weak link in the grid-direct installation. Overall, I like them both (PVP and SMA). Performance: On page 44 of the Dec/Jan issue of SolarPro, there is a list of specifications for grid-direct inverters. Current PVP and SMA inverters have similar CEC weighted efficiency ratings. Some of the older PVP inverter models (1100, 2000, 2800, 3000) have slightly lower efficiency. Reliability: I like that the PVP inverters have no moving parts, whereas the SMA inverters use a fan to assist with the cooling. PV Powered does a lot of marketing around their reliability efforts, for whatever that's worth. Customer Service: I have not needed to utilize PV Powered customer service. I've found SMA customer service techs to be easy to reach and knowledgeable. Other issues: I like that PV Powered inverters are made in the USA. I also find the hardware and manuals to be easier to work with, most likely because they're produced in the USA for our market. The PVP inverters ship with a full-size mounting template which comes in handy, especially when planning the rough-in wiring and support framing during new construction. I have a preference for the PVP inverters, and use SMA occasionally if it's a better design fit. I agree with Wayne Irwin's comment about the durability of the inverters with the heavy transformer designs, as opposed to the newer light-weight designs (including the newest SMA products). I just feel that in the long run, lower counts for electronic components is a good thing. I'm not an expert on component reliability, but I know from my somewhat limited experience that capacitors dry up and transistors are susceptible to a variety of failure modes. The fewer of these things, the better. Also from a reliability standpoint, I prefer to put inverters inside in a well ventilated area, if possible. My gut feeling is that over the long haul, any inverter will be better off in a location that is protected from moisture and large ambient temperature swings. -Hans From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Keith Cronin Sent: Tuesday, December 01, 2009 1:04 PM To: RE-Wrenches Subject: [RE-wrenches] PV Powered vs SMA Hi colleagues Do any of you have a preference, PV Powered vs SMA in the residential space- 2k-5k grid tie inverter zone? Comments on performance/reliability/customer service etc? Any feedback on their monitoring vs SMA's webbox? Thanks Keith ___ 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] wiring the Soladeck
The 2-hole strain relief is called a cable gland. TB makes a line that includes 2-hole, 3-hole, 4-hole etc. The part numbers all begin with CC-NPT-*. The 2-hole gland is CC-NPT-12-G-2. You can find the complete selection on the last page of this PDF: http://tnblnx3.tnb.com/emAlbum/albums//tc_us/tc_1_ltnonmettalicflex.pdf Be aware the diameter of the wires (USE or PV-wire) that you're running through the gland and make sure you order a part that has the right size holes. I like to run my #6 copper EGC through a gland or cord grip as well. The TB cable glands are not UV resistant, so you don't want to use them where exposed to sunlight (i.e. keep the Soladeck under the array). I've got a collection of UV-resistant cable glands but I can't remember the manufacturer. The problem with those is that they aren't UL listed. If it's not one problem, it's another... The manufacturer of the Soladeck is RSTC Enterprises: http://www.rstcenterprises.com/pdf/soladeck_brochure.pdf I spoke with them a while back when I was getting sorted out with cable glands and the guy I talked to claimed he was working on getting a line of cable glands to sell with the Soladeck. I haven't seen this from any of the suppliers however. Regards, -Hans From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Mick Abraham Sent: Tuesday, November 24, 2009 2:43 PM To: RE-wrenches Subject: Re: [RE-wrenches] wiring the Soladeck I drill where the dimples are in the sheet metal, then punch for .5 trade size, then install one of the plastic two hole strain relief clamps as are available from AEEsolar and others. I feel that one must not rely on the foam lid gasket to sufficiently clamp the power leads. That just seems like asking Murphy to impose the Law. The conductor for grounding the metal array parts can just exit through a drilled hole in the box with no strain clamp, because there's a metal loop that this wire can first loop through to give some tug prevention. Jolliness, Mick Abraham, Proprietor www.abrahamsolar.com Voice: 970-731-4675 On Tue, Nov 24, 2009 at 3:12 PM, Dave Click davecl...@fsec.ucf.edu wrote: Wrenches- How are folks wiring the Soladeck boxes? It seems that the intent is to use cord grips in the south end of the box, but I just saw another installation where the wires just came directly in through the space at the south end. Seems like the foam is included to keep bugs out rather than provide strain relief to those incoming conductors, so I guess I'm just looking for a reality check here. Thanks and happy Thanksgiving! DKC ___ ___ 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] AC DC in Raceway
I am not aware of any type of installation where the NEC would require bundling in a gutter. I have seen some non-metallic raceways with built-in partitions for low-voltage and line-voltage wiring, but of course this type of product wouldn't be applicable for the AC/DC separation you're looking for. Anyway, you should be careful with bundling, because although it makes for a neat installation, your AHJ might consider tightly grouped conductors in a gutter as requiring derating, as if they were sharing a raceway. Typically this would not be an issue for solar installations, since we're increasing wire sizes over minimum requirements in order to minimize voltage drop / wire resistance losses, but if you had say, five strings, and you bundled the 10 DC wires together for a distance of 24 or more, your derating factor may have just hit 50%, and that's in addition to any derating that might be required by ambient temperature. Just keep in mind that any current carrying conductors that are bunched together with zip ties just might run a bit warmer and thereby have increased resistance. I heard a story somewhere once about a homeowner who thought it would be very workmanlike to _braid_ all the home runs together as they left the service panel. According to the story, the AHJ took a dim view of this and wrote an ampacity correction based on NEC 310.15(B)(2) Adjustment Factors for More Than Three Current-Carrying Conductors in a Raceway of Cable. This makes sense when you consider that the braided romex was essentially one big cable. -Hans Hans Frederickson Project Manager Frederickson Electric, Inc. www.fredelectric.com From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Drake Chamberlin Sent: Thursday, September 24, 2009 2:19 PM To: RE-wrenches Subject: Re: [RE-wrenches] AC DC in Raceway Bundling is a good idea, I to that too. But where does it say we have to do it? At 09:43 AM 9/24/2009, you wrote: Nik, we always use 4x4 gutters when ever possible - keeps things clean and neat - as long as insulation voltage rating is same on all wires and wires are bundled (AC and DC - tie wraps or tape) and it's all from the same system (house wiring is another system) then it's OK... Max Balchowsky SEE Systems From: Nicholas Ponzio, Building Energy npon...@buildingenergyus.com To: RE-wrenches re-wrenches@lists.re-wrenches.org Sent: Thursday, September 24, 2009 4:02:21 AM Subject: [RE-wrenches] AC DC in Raceway Wrenchers, What's the deal with mixing AC and DC conductors in a raceway? The job in question has a 6x6 wireway under the inverters. Conductors will have their own conduits but is it ok for them to share the wireway? Thanks in advance for clarification on this, Nik -- Nicholas Ponzio Building Energy 1570 South Brownell Road Williston, VT 05495 t: 802-859-3384 x15 f: 802-658-3982 www.BuildingEnergyVT.com Building Solutions for a Sustainable Future ___ 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 http://www.members.re-wrenches.org/ Drake Chamberlin Athens Electric OH License 44810 CO License 3773 NABCEP TM Certified PV Installer Office - 740-448-7328 Mobile - 740-856-9648 ___ 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] Thermal issues with PVC (was RE: raintite boxmounting angle)
Slipped pinky finger sent my post a bit early. Sorry... Here's the Carlon document for PVC expansion fittings: http://www.carlon.com/Installation_Training/IT-ISEXPJT.pdf My feeling is that in general, how thermal expansion/contraction issues are handled is one of the most important factors in the longevity of solar PV installations. Not just for conduit, but for racking and module construction as well. If I recall correctly, an expansion coupling (or lack thereof) was the cause of the Staples fire. -Hans -Original Message- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Hans Frederickson Sent: Monday, August 24, 2009 3:33 PM To: 'RE-wrenches' Subject: [RE-wrenches] Thermal issues with PVC (was RE: raintite boxmounting angle) Picking up on Max's comment about PVC conduit coming apart in the heat... PVC is acceptable for use above ground, but is often not a good choice in exposed outdoor areas due to thermal issues: First, PVC conduit is not permitted to be used where ambient temperatures exceed 50 degrees C (122 degrees F) per NEC 352.12(D). This limitation rules out using PVC on most roofs, although you will occasionally see it used on cool roofs in our neck of the woods (pacific NW). It follows that PVC junction boxes would not typically be a good idea on a hot roof unless they are specifically listed for higher temperatures. Second, PVC of any significant length installed outdoors generally will require an expansion fitting. See NEC 352.44 for details. The rule of thumb we use around here is any piece of PVC conduit longer than 10' installed on an exterior wall needs an expansion fitting. If you find yourself needing to install an expansion fitting, this document from Carlon is very helpful: ___ 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] Fall protection anchors for comp shingle roofs
Andrew, This is my favorite: http://www.superanchor.com/retrofit.html It has a butyl strip under the steel strap which helps seal the nail penetrations, and if you install it properly, all of the penetrations will end up underneath the ridge shingles. When you're done, you can just leave it for future maintenance use. We use roof accessory spray paint to help them blend in with the roof. Regards, -Hans From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Andrew Truitt Sent: Wednesday, July 29, 2009 10:03 AM To: RE-wrenches Subject: [RE-wrenches] Fall protection anchors for comp shingle roofs Has anyone found roof anchors that are designed to span the ridge cap on existing composition shingle roofs? We have a number of different types of anchors that we attach on the north side of the roof with screws into the truss but that invariably leaves the issues that result from running a rope over the peak: crushing the ridge cap, damaging the ridge cap shingles, wear on the rope, etc... We use the carpet or cardboard on the ridge method but it is imperfect. We have one anchor that is designed to span the ridge on unfinished roofs with a 6 leather strap but it won't span most ridge caps. I'm looking at the Guardian Fall Protection catalog - which is awesome - but it doesn't have anything for this particular application. Thoughts? Andrew Standard Solar Inc. -- 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
Re: [RE-wrenches] Magnum MS4448AE Compatibility Question
A few years back, we had a customer who was having similar problems. I don't recall if it was a Buderus boiler, but the generator was a Generac. This was a simple generator backup system. We were able to get the boiler to work reliably after adjusting the governor on the generator so that it ran at 60Hz under load. As I recall, it would then drift above 60Hz when unloaded. If you were to try a UPS, it would need to be a dual-conversion type to make a difference, otherwise it would just pass the generator power straight through. True dual-conversion UPS units are very expensive... Probably costing more than the cheap generator in many cases. -Hans -Original Message- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Howie Michaelson Sent: Wednesday, February 11, 2009 6:52 AM To: RE-wrenches Subject: Re: [RE-wrenches] Magnum MS4448AE Compatibility Question I installed an off-grid system with identical symptoms: OB VFX 3648 dual stack Buderus GB142-24 Kohler 12 kW propane genny The boiler runs fine on the inverter power, but will occasionally error out (6A) and shut down while the generator is running (usually after it has been on for hours). The plumber installed an APC uninterruptable power supply/surge suppressor (not sure of the model) before the boiler, but when running on the internal inverter, the symptoms seemed to get worse. When running on just the surge suppressor portion, the symptoms were the same as if the APC wasn't in-line. We've checked the grounding at the genny, made sure the neutral was isolated except for the main panel, still the same problem. Seems this is a Buderus issue (or at least not an inverter one) - see: http://www.buderus.net/Support/TechnicalInfoForums/tabid/132/forumid/15/thre adid/4334/scope/posts/Default.aspx I haven't been able to make the boiler run reliably when the genny is on, which is a problem in our climate, when the client goes away in the winter... Howie -- Howie Michaelson NABCEP Certified Solar PV InstallerT Sun Catcher, LLC Renewable Energy Systems Sales and Service VT Solar Wind Incentive Program Partner http://www.SunCatcherVT.com (cell) 802-272-0004 (home) 802-439-6096 On Wed, February 11, 2009 7:47 am, Darryl Thayer wrote: Some of the hot surface ignitors I have seen draw a lot of current, in the order of amps. I would expect the inverter to drop out if it were overloaded however. Also does the magnum drop voltage at very low loads? Where the furnace controls can not function due to low voltage or poor wave shape. Darryl This may be true about high frequency switching interfering with something, but I believe the problem with this ignitor is that it is a very poor design. Judging by what I read on their company forum, it doesn't look like they have a clue about this problem. Maybe you can go inside the Buderus and filter something there or maybe you can fine another product to try ? boB ___ 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] Florian canopy experience?
Wrenches, I have a customer who is interested in the solar canopy product made by Florian for a bifacial Sanyo array: http://www.floriansolarproducts.com/ So far I've received a fairly limited amount of information from the company regarding the installation process. If anyone has had experience with this product, can you share? I'm particularly interested to know about the installation effort, if there were any hangups, and how you grounded the aluminum channels that frame each module. Thanks, -Hans ___ 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] FMC vs MC Cable
I have seen MC cable used for DC circuits and I don't think it meets the requirements of 690.31(E) for a metallic raceway. I don't think the metal cladding on MC cable qualifies as a raceway any more than the plastic sheathing on romex does, but I've heard differing opinions on this. Last I checked the code process on www.solarabcs.org, there was some discussion on clarifying this point for the 2011 NEC, with some arguing for and some against specifically allowing MC cable. Obviously, MC cable is much easier and faster to install, but I don't think it meets the intent of 690.31(E). My understanding is that firefighters wish to have some protection from DC circuits when they're penetrating a building. We should also concerned about anyone cutting into a wall or ceiling during remodeling, etc. Flexible metal conduit is heavier duty than the cladding on MC cable, and would hold up better against a cutting tool, but FMC is not a good choice for long runs because the friction makes pulling the wire a challenge. It's also very expensive. For our residential new construction pre-wires, we install 3/4 EMT conduit. It takes quite a bit longer (and more skill) than MC, but allows more flexibility in the number of circuits used, and will be safe from any tightening in the code down the line. Regards, -Hans Hans Frederickson Estimator / Project Manager Frederickson Electric, Inc. (360) 385-1395 www.fredelectric.com -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Peter Parrish Sent: Monday, October 27, 2008 10:08 AM To: 'RE-wrenches' Subject: [RE-wrenches] FMC vs MC Cable On new construction, we like to run MC cable throughout the building shell, from the PV modules to the inverter. We of course include a properly rated DC disconnect before or just after penetrating the shell and use protection plates when we run through studs. And we probably will need to add labels soon in many jurisdictions. My question is as follows: What are the implications of using flexible metal conduit and pulling the wires ourselves vs using the pre-wired MC cable? Both jackets are Al. - Peter Peter T. Parrish, California Solar Engineering, Inc. 820 Cynthia Ave., Los Angeles, CA 90065 Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885 CA Lic. 854779, NABCEP Cert. 031806-26 [EMAIL PROTECTED] ___ 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] Getting GFDI Open Message When It's Not
Greetings wrenches, This is my first post. I ran into this with an SB3000 back in June. I called SMA tech support and spoke to Jake, who was familiar with the problem. His explanation was that there was a series of boards that got some excess lacquer sprayed on them at the factory. This lacquer coats the pins, so the jumper doesn't make a good electrical connection. Jake recommended removing the jumper and scratching off the outer layer of the pins with a razor blade before replacing the jumper. I went gently at first and it worked for a while and then failed again the next time I disconnected the system. Then I went after the pins with gusto on all four sides, removing some metal, and the inverter has been working fine since June. I would recommend having your customers keep an eye out for the GFDI OPEN disturbance if you've only fiddled with the jumper, since that connection would probably be fairly susceptible to failure, assuming the problem is with the lacquer coating. As an aside, I found the SMA tech support line to be very friendly, knowledgeable, and expedient. -Hans Hans Frederickson Frederickson Electric Port Townsend, WA www.fredelectric.com _ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Kelly Keilwitz, Whidbey Sun Wind Sent: Monday, September 22, 2008 9:37 PM To: RE Wrenches listserve Subject: Re: [RE-wrenches] Getting GFDI Open Message When It's Not Hi All, We've seen this on 2 SMA SB's (one a 3000; can't recall the other) this year. In both cases we got it to work by fiddling with the jumper. Another installer recommended that trick. -Kelly Kelly Keilwitz, P.E. Whidbey Sun Wind, LLC Renewable Energy Systems NABCEP Certified PV Installer 987 Wanamaker Rd, Coupeville, WA 98239 PH FAX 360-678-7131 [EMAIL PROTECTED] On 9/22/08 4:08 AM, design [EMAIL PROTECTED] wrote: I have also seen this GFDI OPEN message on a few SB3000US units. I have managed to get the unit to boot properly by switching it off, pulling the GFDI fuse out, slightly crimping the fuse clips to make them tighter, then putting fuse back in and switching it on. This may have actually had an affect, or it may have simply been the restart that did it. In any case it seems like this may be a more common occurrence than SMA knows. Two units required one restart, one unit took three before it finally booted correctly. Jim Grundy NABCEP Certified Solar PV InstallerT Vermont Solar Specialist Plumber PS-279 Elemental Energy, Inc. 1750 Clark Rd E. Montpelier, VT 05651 802-476-3441 (p) 802-476-5680 (f ) 802-272-8933 (c) ___ 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
