Hi Jay, Is this for an inverted output circuit? If so then I think the NEC reference you’re looking for is 705.95(B). That says you can size the neutral to the same size as the EGC if the neutral is used only for instrumentation, voltage detection or phase detection.
A number of single phase inverters these days do not require a neutral at all, so if the AHJ will not accept downsizing it may be worth changing inverters. Garrison > On Sep 22, 2018, at 6:07 PM, Glenn Burt <[email protected]> wrote: > > Here is the code reference explaining this conductor size disparity from 2017 > NEC: > > "According to Table 310.15(B)(16), a 3/0 AWG, Type THW copper conductor > has an ampacity of 200 amperes. However, for a 3-wire, single-phase > dwelling unit service, as shown in Exhibit 215.2, 310.15(B)(7) permits a > service conductor (or a main power feeder conductor) with an ampacity > of 83 percent of the service rating. This permits a minimum of 2/0 AWG, > Type THW copper conductors or 4/0 AWG, Type THW aluminum conductors > for services or a main power feeder rated at 200 amperes" > > -Glenn > > -----Original Message----- > From: RE-wrenches <[email protected]> On Behalf Of > Dana > Sent: Saturday, September 22, 2018 10:32 AM > To: 'RE-wrenches' <[email protected]> > Subject: Re: [RE-wrenches] Neutral sizing > > What about 4/04/02/0 aluminum, service feed? Or is that utility excepted? > > ---------------------------------------------------------------------------- > Dana Orzel Great Solar Works, Inc. > C - 208.721.7003 [email protected] > Idaho Contractor - # 028765 Idaho PV # 028374 > NABCEP # 051112-136 www.solarwork.biz > "Responsible Technologies for Responsible People since 1988" > Please consider the environment before printing this email. > > > -----Original Message----- > From: RE-wrenches <[email protected]> On Behalf Of > Marco Mangelsdorf > Sent: Friday, September 21, 2018 10:39 PM > To: 'RE-wrenches' <[email protected]> > Subject: Re: [RE-wrenches] Neutral sizing > > At the risk of sounding like a grandpa Wrench...I've never had or seen a > neutral conductor be smaller than current carrying. > > marco > > -----Original Message----- > From: RE-wrenches [mailto:[email protected]] On > Behalf Of Jay > Sent: Friday, September 21, 2018 3:47 PM > To: [email protected] > Subject: [RE-wrenches] Neutral sizing > > Hi all, > > I’m wondering if there is code reference to size of neutral vs power > conductors. > > County is requiring neutral same size as mains 240vac. > As it’s 500 mcm due to VD (200 amp service) it’s a non trivial expense. > > I know that where I live, the utility brings in a smaller neutral than L1/L2 > > Thanks in advance > > Jay > > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: [email protected] > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/[email protected]/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org > > > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: [email protected] > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/[email protected]/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org > > > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: [email protected] > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/[email protected]/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org > > > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: [email protected] > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/[email protected]/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org > _______________________________________________ List sponsored by Redwood Alliance List Address: [email protected] Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/[email protected]/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
