[RE-wrenches] Supply Side Tap Overcurrent Protection

[Bob-O Schultze]

Dave,
OK, here's my shot at this. Your mileage may vary. I think 240.86(A) applies here. Unless the CB in the Xantrex XW has a higher interrupt ratting (AIC) than the available fault current from that supply side tap and the CB is so marked (240.83(C), a disconnect using appropriate current limiting OCD devices is required. I've never done a supply side tap without the disco being fused with current limiting fuses, nor have I ever heard of one that wasn't current limit protected being approved.
Good Luck, Bob-O
ps you travel without your Code book? :)


On Mar 28, 2010, at 10:52 AM, Dave Palumbo wrote:

Wrenches,
 
I am tasked with reviewing an installation by a licensed electrician in Vermont and would like help with the following:
 
Grid-tied PV system with battery back-up. AC point of connection is a supply side tap (done on customer side of utility meter ) then traveling 5 feet of #2 THHWN in 1” EMT to the 60 Amp 240vac Lockable Utility Disconnect (unfused) and continuing 15 feet #2 THHWN 1” EMT to Xantrex XW 60 Amp breaker.
 
I had said that the 60amp 240vac lockable disconnect needed to be fused, and received the following reply from the installing electrician.
 
<< “The Xantrex XW Power Distribution Panel contains the required over current protection (60 amp
double pole circuit breaker) negating the need for a redundant fuse at the Utility Disconnect switch.” >>
 
I am on a short trip in Florida and away from my code books. Can someone provide guidance and code reference please? I am concerned about the 20 foot distance of the un-protected circuit from the supply side tap and also the interrupt rating of the 60 Amp breaker in the Xantrex distribution panel.
 
David Palumbo
Independent Power LLC
Offices in Lamoille and the Champlain Valley
802.888.7194
www.independentpowerllc.com

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