Hi Ray and All, 250.166 says the GEC must be sized as specified in (A) Not smaller than the neutral conductor, or (B) Not smaller than the largest conductor supplied by the system, except as permitted by (C) through (E).
A water main [as in 250.52(A)(1)] is not listed as an exception in (C) through (E). So if the GE is a water main wouldn't the GEC "need" to be 4/0, if the battery cables were 4/0? Not saying it makes sense, especially if the water main is 3/4", but this has always made me wonder. Thoughts? Garrison Riegel Project Manager | Solar Service Inc [p] 847-677-0950 | garri...@solarserviceinc.com NABCEP Certified PV Installation ProfessionalT -----Original Message----- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Ray Walters Sent: Tuesday, April 16, 2013 12:52 PM To: RE-wrenches Subject: Re: [RE-wrenches] Fuse sizing in battery circuits Hi Drake; Read down a bit more and 250.166(C) and (D) limit the size of the GEC to #4 or #6 max., depending on what electrode is used. This used to not be the case, and systems in the 90s had 4/0 cable to a 5/8" electrode: which just like your 1/2" pipe example was absolutely ridiculous. R.Ray Walters CTO, Solarray, Inc Nabcep Certified PV Installer, Licensed Master Electrician Solar Design Engineer 303 505-8760 On 4/16/2013 9:31 AM, Drake wrote: > > > So, in a standard battery system, with a charge control, ground fault > protection and an array, the DC system will likely need grounding. If > the DC system is grounded, then the battery cables are grounded also. > In 250.166 (B) it says the grounding electrode conductor (GEC) shall > not be smaller than the largest conductor supplied by the system. > > If the battery cables are "supplied by the system" doesn't this imply > that the GEC should be the size of the battery cable? This is the > logic that has led some inspectors to require a 4/0 copper wire to be > bonded to a 1/2" water pipe. This is, of course, technically absurd. _______________________________________________ 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
