That complicates it a bit. If you have 200A coming in from the grid, and another 200A coming in from the inverters (4 x 48A = 192A), you will need to size the wire to the transfer switch for 400A. In a fault condition, you could potentially see that much amperage on those wires before the 200A grid breaker trips (which will cause the grid-tie inverters to shut down).
Brian Teitelbaum AEE Solar -----Original Message----- From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of penobscotso...@midmaine.com Sent: Thursday, June 15, 2017 4:33 PM To: RE-wrenches Subject: Re: [RE-wrenches] Question Sorry, 200 amp main breaker in a 400 amp rated panel. > Hi Daryl, > > From your description, yes, if you are attaching to lugs connected to > busses and then to the 400A main breaker, with no other overcurrent > device between, you would have to size the wire for the 400A rating. > > Brian Teitelbaum > AEE Solar > > -----Original Message----- > From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] > On Behalf Of penobscotso...@midmaine.com > Sent: Thursday, June 15, 2017 4:10 PM > To: RE-wrenches > Subject: Re: [RE-wrenches] Question > > I re-read and see that I need to clarify my earlier question. The 400 > amp, > 120/208 panel has a main breaker that will be used for the utility > input, coming in on 3/0 copper. The four 60 amp breakers will be used > because the four 10 kW inverters maximum ac output is 48 amps each (x > 1.25 =60 amps ocpd). On the opposite end of the 400 amp panel there > are main lugs which will be used to feed the generator transfer > switch, essentially, because the inspector says we cannot put more > than "two in, one out" on the gentran. These wires to the gentran are > what I am wondering how best to size. Common sense tells me they > should be rated the same as the main panel breaker from the utility. Is this a correct assumption? > > >> Esteemed wrenches, >> We're working often in the Bahamas and now that net metering is >> approved there, the inspectors are far behind in their comprehension. >> That said, we are currently required to combine the utility with the >> PV in a main load center before going to the generator transfer >> switch. I have a 400 amp rated load center with a 200 amp, 120/208 >> main breaker on it, as well as four 60 a, 3 pole breakers that will >> be fed from four >> 10 kw inverters. My question is, will it be necessary to use wire >> rated at 400 amps or can I use wire rated for the main breaker? Thank >> you for your input. It might be a stupid question, but I am stymied >> here....it might just be the Lyme, not sure.....oh, and it's CEC 2015 >> down there, but I suspect it will align with NEC 2014. >> >> Thanks again, >> Daryl DeJoy >> NABCEP Certified PV >> Penobscot Solar Design >> >> _______________________________________________ >> List sponsored by Redwood Alliance >> >> 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 >> >> List-Archive: >> http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillis >> t >> .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: RE-wrenches@lists.re-wrenches.org > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist > .htm > l > > 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: RE-wrenches@lists.re-wrenches.org > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/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: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.htm l 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: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
