[RE-wrenches] sizing a sub-panel used to combine multiple inverter outputs

[Mark Frye]

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-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at 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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