# 400 amp services



## racerjim0 (Aug 10, 2008)

First off, around here we have several different counties/cities/jurisdictions that use different NEC code book years with various exceptions to those books. 
Now for the question/opinion part:
I used to do a lot of 400 amp services with 500 mcm in 4" conduit.
Since 500 mcm can no longer be used for 400 amp stuff anymore is everyone just running parallel 3/0 wire. I think its time to get rid of my 500 mcm stash. I know my tugger won't have a problem with it!


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## RePhase277 (Feb 5, 2008)

racerjim0 said:


> First off, around here we have several different counties/cities/jurisdictions that use different NEC code book years with various exceptions to those books.
> Now for the question/opinion part:
> I used to do a lot of 400 amp services with 500 mcm in 4" conduit.
> Since 500 mcm can no longer be used for 400 amp stuff anymore is everyone just running parallel 3/0 wire. I think its time to get rid of my 500 mcm stash. I know my tugger won't have a problem with it!


You feel free to send all that 500 to me. I'll take good care of it:thumbsup:


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## jefft110 (Jul 7, 2010)

racerjim0 said:


> First off, around here we have several different counties/cities/jurisdictions that use different NEC code book years with various exceptions to those books.
> Now for the question/opinion part:
> I used to do a lot of 400 amp services with 500 mcm in 4" conduit.
> Since 500 mcm can no longer be used for 400 amp stuff anymore is everyone just running parallel 3/0 wire. I think its time to get rid of my 500 mcm stash. I know my tugger won't have a problem with it!


The 500cu is still good for 400a sf. dwelling.

Commercial: parallel 3/0cu in separate conduits will work, otherwise 4/0cu.


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## Shockdoc (Mar 4, 2010)

jefft110 said:


> The 500cu is still good for 400a sf. dwelling.
> 
> Commercial: parallel 3/0cu in separate conduits will work, otherwise 4/0cu.


Parallel 3/0 is about $3 cheaper per ft. than 500mcm and easier to pull . Why feed the copper gods ?


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## jefft110 (Jul 7, 2010)

Shockdoc said:


> Parallel 3/0 is about $3 cheaper per ft. than 500mcm and easier to pull . Why feed the copper gods ?


Yeah, I agree but if I had a stash of 500 laying around like the op said he had, I'm using it.


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## Dennis Alwon (May 9, 2009)

Racer if the calculated load on the building is 380 amps or less then the 500 cu is still good for a 400 amp breaker.


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## Shockdoc (Mar 4, 2010)

jefft110 said:


> Yeah, I agree but if I had a stash of 500 laying around like the op said he had, I'm using it.


 By all means, I would too.


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## wirenut71 (Dec 5, 2010)

I just finished building a 400amp service for an office building using 4" conduit and 500mcm.


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## jefft110 (Jul 7, 2010)

Dennis Alwon said:


> Racer if the calculated load on the building is 380 amps or less then the 500 cu is still good for a 400 amp breaker.


Right. 380 is not a standard breaker size and 400 is the next one up.


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## nitro71 (Sep 17, 2009)

jefft110 said:


> Right. 380 is not a standard breaker size and 400 is the next one up.


But how would that work if you feed two 200 amp disconnects? I'm a little foggy on that application. Say your load calc is 380 amps and you feed the meter with that 500 CU. Can you use two 200 amp discos? Without digging into it I'm "betting" you can?


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## HARRY304E (Sep 15, 2010)

nitro71 said:


> But how would that work if you feed two 200 amp disconnects? I'm a little foggy on that application. Say your load calc is 380 amps and you feed the meter with that 500 CU. Can you use two 200 amp discos? Without digging into it I'm "betting" you can?


:laughing: You can run the 500's in parallel and use a 400 amp breaker..


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## nitro71 (Sep 17, 2009)

HARRY304E said:


> :laughing: You can run the 500's in parallel and use a 400 amp breaker..


But what if I don't have a 400 amp breaker :whistling2: and only have a two 200's :thumbup:


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## HARRY304E (Sep 15, 2010)

nitro71 said:


> But what if I don't have a 400 amp breaker :whistling2: and only have a two 200's :thumbup:


Thats fine you can use 500's on 200 amp breakers.Just don't lode up each breaker with 400 amps.


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## nitro71 (Sep 17, 2009)

Thanks Harry, course I should do some research but I'm tired. Yawn..


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