[RE-wrenches] Supply Side Tap Overcurrent Protection

[Nick Soleil]

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 <billbrooks7 at yahoo.com>
To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
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:re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org] 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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