[RE-wrenches] Adding on to existing PV System

[Glenn Burt]

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.

 

-Glenn

 

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).

 

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.

 

Does anyone see any problem with doing a supply size connection for the new
system? Any labeling snags that I might need to consider?

 

Jason Szumlanski

Fafco Solar

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20110929/f9e261de/attachment-0003.html>