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
