Feeder protection

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preben

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I have a slightly unusual situation for the service/load center for a single family dwelling.
The main 200A circuit breaker is in an outdoor panel with a load center and auxiliary load lugs.The panel is located 35' from the house on a pedestal.
In the house we have a 200A convertible main lug.The feeder cable from the main disconnect to the main lug is USE 2/0 in a conduit.As the feeder wires ampacity exceed 200A, is it necessary to use an additional and smaller breaker in the main lug? Does NEC 240-21m apply here?
 
Re: Feeder protection

240-21(m)? You must be using a 1996 NEC?

Section 240.21 deals with Feeder Taps which is not what you are describing. The code generally requires conductors to be sized not less than the OCD that protects them. By increasing you conductor size, you do increase the current-carrying capacity of the feeder, but the overcurrent protection still limits the current to the rating of the panelboard.

So no, 240.21 does not apply, and you do not need an additional breaker in the panelboard. Check out section 384 I believe if you are indeed on the 1996 version.
 
Re: Feeder protection

2/0 USE CU ampacity is 175 Amps according to Table 310-16. I would think that the conductors are not protected by a 200 Amp breaker.
 
Re: Feeder protection

If you consider this feeder as the main power feeder, then Table 310.15(B)(6) would be permitted to be used. 2/0 is good for 200A per that table.
 
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