[RE-wrenches] Supply Side Tap Overcurrent Protection

Bill Brooks billbrooks7 at yahoo.com
Sun Mar 28 22:04:22 PDT 2010


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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