[RE-wrenches] Adding on to existing PV System

[Jesse Dahl]

Maybe you can put in a smaller main breaker? 

Jesse

Sent from my iPhone

On Sep 29, 2011, at 1:39 PM, "Glenn Burt" <glenn.burt at glbcc.com> wrote:

> How about feeding both systems into an AC combining subpanel before feeding the main load center?
> 
> Often the calculations required will allow you to do more backfeeding than the simple backfeeding a load center with individual breakers.
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> -Glenn
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> From: re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Jason Szumlanski
> Sent: Thursday, September 29, 2011 11:49 AM
> To: RE-wrenches
> Subject: [RE-wrenches] Adding on to existing PV System
> 
>  
> 
> We’ve been contracted to add on to an existing PV system in a residence. The existing system has a 30A 2P Breaker on a 200A rated panel with a 200A main breaker. The new system would require a 15A breaker, which would exceed the limit in NEC 690.64(B)(2).
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> The existing system has a fusible AC disconnect mounted next to the meter. This was originally intended as the utility external disconnect. The utility no longer requires a disconnect, but if we do a supply side connection, we would need a fusible AC disconnect anyway for the new system. I would collocate the new disconnect with the old.
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> Does anyone see any problem with doing a supply size connection for the new system? Any labeling snags that I might need to consider?
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> Jason Szumlanski
> 
> Fafco Solar
> 
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