[RE-wrenches] Supply Side Tap Overcurrent Protection

[Hans Frederickson]

Steven,
I don't think the 60A disconnect for the line-side tap would qualify as part
of the required 100A rating for the residential service. You aren't using it
to supply the house loads. Unless I'm missing something, your proposal
limits the residential service load to only 60A. I suppose you could argue
it with the AHJ... but I think you're going against the intent of the code.
These sections weren't written with any consideration to grid-tied PV
feed-ins.

-Hans Frederickson

-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Steven
Lawrence
Sent: Wednesday, March 31, 2010 11:04 AM
To: re-wrenches at lists.re-wrenches.org
Subject: Re: [RE-wrenches] Supply Side Tap Overcurrent Protection

230.80

"Where the service disconnecting means consists of more than one switch or
circuit breaker, as permitted by 230.71, the combined ratings of all the
switches or circuit breakers used shall not be less than the rating required
by 230.79"


Steven Lawrence


___________________________________
Message: 1
Date: Wed, 31 Mar 2010 10:24:17 -0700
From: "Hans Frederickson" <hans at fredelectric.com>
To: "'RE-wrenches'" <re-wrenches at lists.re-wrenches.org>
Subject: Re: [RE-wrenches] Supply Side Tap Overcurrent Protection
Message-ID: <71328CBB96B745889F63E627C93E8A52 at frederickson.local>
Content-Type: text/plain;	charset="us-ascii"

Anything less than a 100A main is a no-go a for residential service:

NEC 230.79(C):
"For a one-family dwelling, the service disconnecting means shall have a
rating of not less than 100 amperes, 3-wire."

Also, I don't think any AHJ is going to accept a load calculation in lieu of
proper bus sizing in the service. What's to stop the owner from adding loads
later on? I agree with Eric... time for a service upgrade.


-Hans Frederickson
 

-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Steven
Lawrence
Sent: Wednesday, March 31, 2010 9:54 AM
To: re-wrenches at lists.re-wrenches.org
Subject: Re: [RE-wrenches] Supply Side Tap Overcurrent Protection

Why can't you do a line side tap and downsize the main breaker?  Use a 60A
main disconnect for the line side tap, and use a 60A main breaker for the
service panel.  That's similar to what I did except I downsized the 200A
main to a 150A. This also allowed a manual interlock kit in the main service
panel that can be fed from the backup load panel.  

Steven Lawrence
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