# 400 MCM and 400 amp main service.



## Chris Kennedy (Nov 19, 2007)

240.4(B) requires you to protect your 400's at 350A.


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## nitro71 (Sep 17, 2009)

310.15(B)(6) has no bearing on a church. You need to size your conductors off Table 310.16. You could take parallel runs of copper 3/0 XHHW. The 400 you mentioned is only good for 335 amps at 75 degrees.


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## varmit (Apr 19, 2009)

NO

You must use the 75C column to determine your wire size. 400 kcmil at 75c = 335 amp rating. Only residential services allow reduced wire size. Unless you must reuse the existing conduit, it is usually more cost effective and much easier, to parallel (2) sets of 3/0 in (2) conduits.


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## alpha3236 (May 30, 2010)

You didn't mention if you had a 400A main breaker. If you are using a meter main combo, they typically do not have a main, only provisions for sub breakers up to ,I believe 250A. Your meter socket is only rated 320A continuous, and in this case the size of the Service Entrance Conductors is based on the calculated load.


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## solar man (Aug 21, 2010)

Thanks for the help everyone!

I have installed 3" rigid and will have room for the wire.


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## Chris Kennedy (Nov 19, 2007)

Welcome to the Forum.


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## ampman (Apr 2, 2009)

solar man said:


> Thanks for the help everyone!
> 
> I have installed 3" rigid and will have room for the wire.


 so which wire did you decide on:whistling2:


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## frenchelectrican (Mar 15, 2007)

Let see .,,

240mm² { 500 MCM }

Or 

2X 120mm² { 4/0 AWG }

who will vote on that ??

Merci.
Marc


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