500 kcmil feeding a 400 amp service

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don_resqcapt19 said:
The code sections are 230.42 and 230.90(A) Exception #3.
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I agree and that was what I was trying to get to yesterday in this thread.

With two service disconnects 240.4(B) has noting to do with it.
 
Here's 2 paragraphs, one is what's in the NEC, the other I made up all by my lonesome.

230.42(B)
(B) Specific Installations. In addition to the requirements of 230.42(A), the minimum ampacity for ungrounded conductors for specific installations shall not be less than the minimum rating of the service disconnecting means installed.

230.42(B)
(B) Specific Installations. In addition to the requirements of 230.42(A), the minimum ampacity for ungrounded conductors for specific installations shall not be less than the minimum rating of the service disconnecting means specified in 230.79(A) through (D).

Would the real 230.42(B) please stand up ?!

I don't see that the real 230.42(B) ever requires "minimum ampacity for ungrounded conductors" larger than 100a [230.79(C)].

Am I missing something ?

David
 
Dennis Alwon said:
Maybe I am missing something but it seems clear that 400 amps and 500mcm are compatable in this situation.
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Only because there is more than one service disconnect.

Because of that 230.90(A) Exception #3 can be used.
 
If there is only one service disconnect then wouldn't Exception No. 2 apply? This refers them to ratings that conform with 240.4(B)
 
Mr. Bill said:
If there is only one service disconnect then wouldn't Exception No. 2 apply? This refers them to ratings that conform with 240.4(B)
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I agree. It seems that exception 2 allows 240.4(B)
 
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