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-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@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
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