Re: [RE-wrenches] conductors and the 120% rule
Changes to http://www.google.com/url?sa=trct=jq=esrc=ssource=webcd=3cad=rjauact =8ved=0CEoQFjACurl=http%3A%2F%2Fwww.slideshare.net%2Fsolpowerpeople%2Finte rconnection-ruleei=FZcYU5e_LsSi0QH5yICQCQusg=AFQjCNGypW0SbS6-POHt4d82Sxc-- kZ0igsig2=Kz2661LzDghXtx9GwuhOfwbvm=bv.62577051,d.dmQ 2014 NEC Interconnection Rule 705.12 Here's a link to a powerpoint (slideshare.net) by Richard Stovall which clarifies 705.12 using some excellent illustrations. Maybe some have seen it already. Works for me. Contact me off-list if you'd like a pdf version. Kirk Herander VT Solar, LLC dba Vermont Solar Engineering NABCEPTM Certified Inaugural Certificant NYSERDA-eligible Installer VT RE Incentive Program Partner 802.863.1202 From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Brian Mehalic Sent: Wednesday, March 05, 2014 10:02 AM To: RE-wrenches Subject: Re: [RE-wrenches] conductors and the 120% rule A very clarifying change is what I'd call it! First off, rather than being based on the actual breaker size on the inverter output circuit, calcs are instead based on 125% of the inverter rated output current. 705.12(D)(2)(1) addresses Feeders - but only applies when the inverter output circuit connection is made somewhere other than the opposite end of the feeder from the utility supply. This addresses concerns about whether the feeder conductor needs to be larger due to the presence of the additional source of supply, and so long as the inverter isn't connected to the feeder in the middle of it then the existing conductor size should be okay (because if it is at the opposite end of the feeder than there is nowhere where the utility and inverter current will be additive). 705.12(D)(2)(3) addresses Busbars and allows several options, including the familiar 120% rule as you stated in your original post. Also check out 705.12(D)(2)(3)(c) - depending on the load breakers in the subpanel, the 120% rule may not even need to be used (if the sum of the inverter and load breakers is less than or equal to the busbar rating). And remember, even if your AHJ hasn't adopted 2014 yet it is worth having a conversation with them to see if they'll allow you to design the system based on the new Code - after all, in a certain sense, the 2014 NEC is what they meant the 2011 NEC to say! Cheers, Brian Mehalic NABCEP Certified Solar PV Installation ProfessionalT R031508-59 IREC ISPQ Certified Affiliated Instructor/PV US-0132 PV Curriculum Developer and Instructor Solar Energy International http://www.solarenergy.org On Tue, Mar 4, 2014 at 5:21 PM, Kirk k...@vtsolar.com wrote: Is this a code change in 2014 vs 2011 or merely a clarification? Vt has not adopted 2014 yet. What was the original rationale for the 120% rule to apply to conductors in addition to a panel bus? Kirk Herander VSE On Mar 4, 2014, at 6:20 PM, Brian Mehalic br...@solarenergy.org wrote: If the subpanel is at the end if the feeder, and there are no taps in between the main and the sub then I don't see any reason that the conductors need to be any larger than 200 A as there is no where on the feeder conductors where grid and PV current will be additive. The changes in 705.12 in 2014 address this in large part. Brian On Mar 4, 2014, at 2:41 PM, Kirk Herander k...@vtsolar.com wrote: Solaredge 20 kw, 480 3-phase. Good point, but that may be irrelevant. The feed-in subpanel is also powering unrelated loads, which use the neutral as a conductor from the main panel. So 4 conductors from the main. Kirk Herander VT Solar, LLC dba Vermont Solar Engineering NABCEPTM Certified Inaugural Certificant NYSERDA-eligible Installer VT RE Incentive Program Partner 802.863.1202 From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Allen Frishman Sent: Tuesday, March 04, 2014 4:32 PM To: RE-wrenches Subject: Re: [RE-wrenches] conductors and the 120% rule what inverter(s) are you using?In many cases the Neutral is not considered a Current Carying Conductor by the Manufacturer and therefore you only have 3 CCC. Al Frishman AeonSolar (917) 699-6641 tel:%28917%29%20699-6641 - cell (888) 460-2867 tel:%2%29%20460-2867 www.aeonsolar.com http://www.aeonsolar.com/ On Mar 4, 2014, at 4:20 PM, Kirk Herander wrote: Approx.. 50 - 60ft. Kirk Herander VT Solar, LLC dba Vermont Solar Engineering NABCEPTM Certified Inaugural Certificant NYSERDA-eligible Installer VT RE Incentive Program Partner 802.863.1202 From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Ray Walters Sent: Tuesday, March 04, 2014 4:05 PM To: RE-wrenches Subject: Re: [RE-wrenches] conductors and the 120% rule What is the length of the conduit to the subpanel? That will determine whether to apply the derates. R.Ray Walters CTO, Solarray, Inc
Re: [RE-wrenches] Extra Low Voltage
Me again, Maybe that was confusing. Just to clarify this question, I will break it down as follows: What qualifications do you need to legally work on electrical systems in your country/state? Is the circuit voltage a factor, and if there is a different rule for ELV systems, then how is ELV defined? What other factors are applicable such as status (homeowner, installer, paid/unpaid) and location (inside home, wet location, etc)? Thanks for any observations. Hugh On 5 Mar 2014, at 08:34, Hugh Piggott wrote: hi All, I am trying to find some general statements that can be made about the global legal position on who may or may not work on/install extra low voltage (ELV) systems or equipment such as batteries, PV, turbines etc. I understand that in the USA this is a matter for state legislation rather than federal. I'd be interested to learn what rules people follow regarding such work and who can do it, for themselves or for money, in what environment (inside or outside the home for example, dry or wet etc) and at what voltages? The definition of ELV seems to change depending on various factors, one of which is whether it is separated (floating and well insulated) or not. Many of us work with battery systems, and not everyone is a certified electrician. I'd love to know some ground rules. thanks! Hugh Hugh Piggott Scoraig Wind Electric Dundonnell Ross shire IV23 2RE, UK +44 77 1315 7600 h...@scoraigwind.co.uk www.scoraigwind.co.uk ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Extra Low Voltage
New Mexico used to have a low voltage electrician. It was for communications guys, and was limited to under 50 v. Actually pretty useless, since most systems had inverters. Also it wasn't that much harder to just get a regular electrical license. Also, some considered even 24 v systems to be over 50 v, since the Voc in cold weather could exceed 50v. Generally, for maintenance/ battery replacement on off grid stuff, no one worries about it. If you are doing new construction, pulling permits, then you need to have much more than just the license. Insurance, bonding, worker's comp, etc. are also all required. R.Ray Walters CTO, Solarray, Inc Nabcep Certified PV Installer, Licensed Master Electrician Solar Design Engineer 303 505-8760 On 3/6/2014 6:33 PM, Hugh Piggott wrote: Me again, Maybe that was confusing. Just to clarify this question, I will break it down as follows: * What qualifications do you need to legally work on electrical systems in your country/state? * *Is the circuit voltage a factor*, and if there is a different rule for ELV systems, then how is ELV defined? * What other factors are applicable such as status (homeowner, installer, paid/unpaid) and location (inside home, wet location, etc)? Thanks for any observations. Hugh On 5 Mar 2014, at 08:34, Hugh Piggott wrote: hi All, I am trying to find some general statements that can be made about the global legal position on who may or may not work on/install extra low voltage (ELV) systems or equipment such as batteries, PV, turbines etc. I understand that in the USA this is a matter for state legislation rather than federal. I'd be interested to learn what rules people follow regarding such work and who can do it, for themselves or for money, in what environment (inside or outside the home for example, dry or wet etc) and at what voltages? The definition of ELV seems to change depending on various factors, one of which is whether it is separated (floating and well insulated) or not. Many of us work with battery systems, and not everyone is a certified electrician. I'd love to know some ground rules. thanks! Hugh Hugh Piggott Scoraig Wind Electric Dundonnell Ross shire IV23 2RE, UK +44 77 1315 7600 h...@scoraigwind.co.uk mailto:h...@scoraigwind.co.uk www.scoraigwind.co.uk http://www.scoraigwind.co.uk/ ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
