Dan:
As I read it, the ampacity of the wire need only be 1/3 of the OCP. And
yes, the OCP for this tap is the 200 amp main, although it can be construed
that the circuit breaker at the down-stream end of the feeder provides
protection as well (if you short the bus the feeder is supplying, the
down-stream CB prevents the feeder from melting due to the 3X ampacity of
the upstream protection).
Also at issue is the question: is the romex wire protected "by other
means"? Judgement call.
See citation below from 240.21(B):
(2) Taps Not over 7.5 m (25 ft) Long. Where the length of
the tap conductors does not exceed 7.5 m (25 ft) and the tap
conductors comply with all the following:
(1) The ampacity of the tap conductors is not less than
one-third of the rating of the overcurrent device protecting
the feeder conductors.
(2) The tap conductors terminate in a single circuit breaker
or a single set of fuses that limit the load to the ampacity
of the tap conductors. This device shall be permitted
to supply any number of additional overcurrent devices
on its load side.
(3) The tap conductors are protected from physical damage
by being enclosed in an approved raceway or by other
approved means.
End of citation
William Miller
At 01:06 PM 10/25/2011, you wrote:
William,
The tap conductor ampacity must not be less than the rating of the breaker
protecting that circuit, which in this case (if I understand the configuration
correctly) would be the main breaker in the panelboard.
Any smaller gauge would require its own OCP device of appropriate rating
if it's to be code-compliant.
Dan
--- On Tue, 10/25/11, William Miller <[email protected]> wrote:
From: William Miller <[email protected]>
Subject: Re: [RE-wrenches] Feeder without a dedicated breaker
To: "RE-wrenches" <[email protected]>
Date: Tuesday, October 25, 2011, 2:54 PM
Jamie:
Thanks for getting me started. I did not think to consider this as a
tap, but it appears to match the criteria.
William Miller
At 11:38 AM 10/25/2011, you wrote:
William, I would start with Article 240.21(B).
Jamie Johnson
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