[RE-wrenches] One renewable disconnect.

[John Wadley]

I think the NEC passages I am recalling (300.3 C 1, 690.4 B) refer to mixing DC and AC in the same conduit, enclosure, etc.  I cannot find anything that would prevent me from disconnecting both wind and solar from the grid in one switch enclosure using a multi-pole switch.  They will be electrically connected (at least on one phase) immediately afterward via the line-side tap.  Anyone know of other restrictions that I am missing? 

Best Regards,
John Wadley, MSEE, PE
NABCEP Certified Solar PV Installer (TM)
Wadley Engineering
214-557-3841

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From: wadleyjk at hotmail.com
To: re-wrenches at lists.re-wrenches.org
Subject: One renewable disconnect.
Date: Wed, 2 Mar 2011 14:36:19 -0700








Wrenches,
      I am designing a system with both wind and solar backfeed and I'm having an issue with the utility.  They say we need to have a single renewable disconnect switch before the grid backfeed.  The solar is designed to backfeed 3-phase through a meter, then a fused AC disconnect to the line-side to avoid upsizing the MDP.  The wind inverter output is 120/240V split-phase (10A) which I had planned to do load-side backfeed through a wind meter with a seperate AC disconnect since it was so small.  To meet the single renewable disconnect requirement, I'm thinking I may need to backfeed the wind on the load-side to one of the three phases.  I guess my question is can I use a single 5 pole fused AC disconnect to control both with one switch handle or is that an NEC violation wrt to merging separate systems within the same conduit?  Or, should I keep them in separate switch boxes with some kind of gang handle?  I have a 3-phase aggregation panel for the solar inverters (6 total, 2 per phase, 240 delta), but if I integrate the wind there in order to simplify the AC disconnect issue, the solar meter will register both solar and wind production.  What is the best practice in this situation?

Thanks,
John Wadley, MSEE, PE
NABCEP Certified Solar PV Installer (TM)
Wadley Engineering
214-557-3841

CONFIDENTIALITY: This communication, including attachments, is for the exclusive use of the addressee(s) and may contain proprietary, confidential or privileged information. If you are not the intended recipient, any use, copying, disclosure, or distribution or the taking of any action in reliance upon this information is strictly prohibited. If you are not the intended recipient, please notify the sender immediately and delete this communication and destroy all copies.

 		 	   		  
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