Opps! My bad, I was thinking of a single phase system, not the three phase system shown in the article. For the three phase system Kent is correct in counting 180A of supply per bar. Mark Frye Berkeley Solar Electric Systems 303 Redbud Way Nevada City, CA 95959 (530) 401-8024 <http://www.berkeleysolar.com/> www.berkeleysolar.com
_____ From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Mark Frye Sent: Tuesday, March 29, 2011 10:17 PM To: 'RE-wrenches' Subject: Re: [RE-wrenches] sizing a sub-panel used to combine multipleinverter outputs I think Kent and I agree. For the case where the subpanel is not dedicated a PV sub-panel he is calculating for 2 - 50A breakers and I calculated for 3 - 50A breakers. Mark Frye Berkeley Solar Electric Systems 303 Redbud Way Nevada City, CA 95959 (530) 401-8024 <http://www.berkeleysolar.com/> www.berkeleysolar.com _____ From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Kent Osterberg Sent: Tuesday, March 29, 2011 9:26 PM To: RE-wrenches Subject: Re: [RE-wrenches] sizing a sub-panel used to combine multiple inverter outputs Per 705.12(D) the sub-panel could be any distribution equipment on the premises. So the question becomes: is the sub-panel capable of supplying branch circuits or feeder loads? If yes, then the sum of the breakers (potentially) feeding the bus is 180 amps so a 150-amp rating is required and the inverters would have to feed the opposite end of the bus bars. If no, the code is not clear on the requirement, but obviously the 80-amp breaker in the main panel limits the maximum current flowing through the sub-panel. Kent Osterberg Blue Mountain Solar
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