[RE-wrenches] Question

Brian Teitelbaum bteitelbaum at aeesolar.com
Thu Jun 15 16:19:10 PDT 2017


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-bounces at lists.re-wrenches.org] On
Behalf Of penobscotsolar at 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
>
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