I have a project were I may need to do a line-side tap, but was wondering if we can provide a load analysis as an exception, to show that the house will never use more than the buss-bars are rated for.
Nick Soleil Project Manager Advanced Alternative Energy Solutions, LLC PO Box 657 Petaluma, CA 94953 Cell: 707-321-2937 Office: 707-789-9537 Fax: 707-769-9037 ________________________________ From: Bill Brooks <[email protected]> To: RE-wrenches <[email protected]> Sent: Sun, March 28, 2010 10:04:22 PM Subject: Re: [RE-wrenches] Supply Side Tap Overcurrent Protection Dave, All line side connections must have overcurrent protection (230.91) at the disconnecting means. Article 230.70 through 230.95 is what generally governs these connections. Without rewriting John Wiles’ articles on this subject, here are a few quick pointers. The basic rule to remember, since you don’t have your code book, is to install a disconnecting means with overcurrent protection adjacent to the existing service. No specific distance is given, but the implication, and the field experience is as close as physically possible to the existing service disconnecting means. Circuit breakers or fused disconnects are allowed if they are listed as service equipment. Fused disconnects are used more often than circuit breakers since many utilities require a visible-break switch. To give Xantrex the benefit of the doubt, their manual probably was not intended to address line side connections. If it is intended to cover these, there statement may be accepted by some jurisdictions, but it quite unlikely that a jurisdiction would ever allow it. To have line side conductors, with no disconnecting means, installed into a PV inverter wiring center just doesn’t make sense. Always install a service disconnect with overcurrent protection on every connection to service conductors—that seems like a logical and simple rule that can never go wrong. Bill. From:[email protected] [mailto:[email protected]] On Behalf Of Dave Palumbo Sent: Sunday, March 28, 2010 10:53 AM To: 'Wrench List' Subject: Re: [RE-wrenches] Supply Side Tap Overcurrent Protection 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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