# 400 amp service



## Dennis Alwon (May 9, 2009)

If you need 3/0 copper to each panel for 200 amp then I would parallel the 3/0. can also get by with 4/0 aluminum but then your load must be under 360 amps. 4/0 alum is good for180 but 240.4(B) allows a 200 amp ocpd


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## Dennis Alwon (May 9, 2009)

Surely you can calculate pipe sizes.No?


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## morg123452000 (Nov 4, 2013)

Dennis Alwon said:


> If you need 3/0 copper to each panel for 200 amp then I would parallel the 3/0. can also get by with 4/0 aluminum but then your load must be under 360 amps. 4/0 alum is good for180 but 240.4(B) allows a 200 amp ocpd


Thanks..i was thinking that too but my local inspector wont allow it..just trying to get some feed back...cant forget derating..i was thinking 6.. 4/0 copper in a 3 inch ridgid conduit..for the feed to meter...4/0 copper is 4 bucks a foot


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## tmessner (Apr 1, 2013)

I would parallel 250 al. Then there is no worry about the limits of 4/0 or 400 amps. We use 250 al almost exclusively for all sizes of parallels. It divides evenly by 2 for parallel conduit runs . It iss easy to work with and is reasonably priced compared to copper.


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## Dennis Alwon (May 9, 2009)

morg123452000 said:


> Thanks..i was thinking that too but my local inspector wont allow it..just trying to get some feed back...cant forget derating..i was thinking 6.. 4/0 copper in a 3 inch ridgid conduit..for the feed to meter...4/0 copper is 4 bucks a foot


I take it you are using 4/0 for de=-rating.


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## Dennis Alwon (May 9, 2009)

morg123452000 said:


> Thanks..i was thinking that too but my local inspector wont allow it..just trying to get some feed back...cant forget derating..i was thinking 6.. 4/0 copper in a 3 inch ridgid conduit..for the feed to meter...4/0 copper is 4 bucks a foot



What won't your inspector allow?


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## Forge Boyz (Nov 7, 2014)

Dennis Alwon said:


> What won't your inspector allow?


It appears he wants to put it all in one pipe. That's why he is derating it. He should just run 2 2" masts so he can run 3/0 copper or 250 aluminum.

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## mofos be cray (Nov 14, 2016)

Forge Boyz said:


> It appears he wants to put it all in one pipe. That's why he is derating it. He should just run 2 2" masts so he can run 3/0 copper or 250 aluminum.
> 
> Sent from my SM-G970U using Tapatalk


I was wondering about the one pipe too. Seems silly, I do it exactly as you describe.


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## morg123452000 (Nov 4, 2013)

Forge Boyz said:


> It appears he wants to put it all in one pipe. That's why he is derating it. He should just run 2 2" masts so he can run 3/0 copper or 250 aluminum.
> 
> Sent from my SM-G970U using Tapatalk


I was thinking of that first to solve the derating..the meter encloser only has one hub opening on top so id have to run out of the side or bottom..that might interfere with my disconnects...all advice welcome


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## Bird dog (Oct 27, 2015)

morg123452000 said:


> I was thinking of that first to solve the derating..the meter encloser only has one hub opening on top so id have to run out of the side or bottom..that might interfere with my disconnects...all advice welcome


Where are you located in the United States? Usually a 400amp service has a CT cabinet & could be large enough to run two conduits out of the top or a jbox with a separate meter can. Talk with your POCO & see what is acceptable to them. They will probably have an engineering book with drawings.


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## morg123452000 (Nov 4, 2013)

Bird dog said:


> Where are you located in the United States? Usually a 400amp service has a CT cabinet & could be large enough to run two conduits out of the top or a jbox with a separate meter can. Talk with your POCO & see what is acceptable to them. They will probably have an engineering book with drawings.


Im in maine...ill look into that...great idea!..any pictures of that setup?


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## Bird dog (Oct 27, 2015)

morg123452000 said:


> Im in maine...ill look into that...great idea!..any pictures of that setup?


All my elctrical work was in the Southeastern US. We have numerous members from your area & maybe they'll chime in. Besides, a 400amp service should be pretty basic.


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## morg123452000 (Nov 4, 2013)

Bird dog said:


> All my elctrical work was in the Southeastern US. We have numerous members from your area & maybe they'll chime in. Besides, a 400amp service should be pretty basic.


Everything is basic after its done once ..lol


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## Forge Boyz (Nov 7, 2014)

morg123452000 said:


> I was thinking of that first to solve the derating..the meter encloser only has one hub opening on top so id have to run out of the side or bottom..that might interfere with my disconnects...all advice welcome


Are you using a 320A meter base? That's what it sounds like to me. Do you have your calculated load for the building? That may help you out in this case. And for this job you should maybe think about not using parallels to go up the mast. Then you wouldn't have to worry about derating. You might be able to get away with 500 MCM copper depending on your load.

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## morg123452000 (Nov 4, 2013)

Forge Boyz said:


> Are you using a 320A meter base? That's what it sounds like to me. Do you have your calculated load for the building? That may help you out in this case. And for this job you should maybe think about not using parallels to go up the mast. Then you wouldn't have to worry about derating. You might be able to get away with 500 MCM copper depending on your load.
> 
> Sent from my SM-G970U using Tapatalk


Yes a 320 meter encloser 500 sounds pricey..ill price it monday...thanks might be the best solution


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## kb1jb1 (Nov 11, 2017)

I was watching the You Tube again the other day and was surprised to see many areas allow the 320 meter pan for a 400 amp service. Here , PSE&G won't. Trans S or CT cabinet. Now I see why many here post about using the 320 amp self contained pan for a 400 amp service. But can you legally sell it as a 400 amp service? Can the HO turn around and sue for not providing a true 400 amp service?


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## morg123452000 (Nov 4, 2013)

kb1jb1 said:


> I was watching the You Tube again the other day and was surprised to see many areas allow the 320 meter pan for a 400 amp service. Here , PSE&G won't. Trans S or CT cabinet. Now I see why many here post about using the 320 amp self contained pan for a 400 amp service. But can you legally sell it as a 400 amp service? Can the HO turn around and sue for not providing a true 400 amp service?


Im going to check and see if i can buy one ...all the supplyers around here sell the 320s
The power company has to aaporove it....cant see why they wouldnt being higher current


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## varmit (Apr 19, 2009)

You say that this is a commercial service? Most areas will not allow a 320 amp meter base for a 400 amp commercial service. Also, you will not be able to downsize the service conductors as in residential. If you parallel the service conductors, the minimum size is 3/0 copper or 250 aluminum for a 400 amp commercial service. If you used a single set of service conductors to the meter base, they would need to be 500 kcmil copper or 750 aluminum.

If you can prove that the connected load will be less than 300 amps, you may be able to use the meter base, that you have, and install a 300 amp service. 

As always, any advice that you receive on an online forum needs to be verified with your local AHJ, as service requirements can vary considerably from one location to another.


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## morg123452000 (Nov 4, 2013)

varmit said:


> You say that this is a commercial service? Most areas will not allow a 320 amp meter base for a 400 amp commercial service. Also, you will not be able to downsize the service conductors as in residential. If you parallel the service conductors, the minimum size is 3/0 copper or 250 aluminum for a 400 amp commercial service. If you used a single set of service conductors to the meter base, they would need to be 500 kcmil copper or 750 aluminum.
> 
> If you can prove that the connected load will be less than 300 amps, you may be able to use the meter base, that you have, and install a 300 amp service.
> 
> As always, any advice that you receive on an online forum needs to be verified with your local AHJ, as service requirements can vary considerably from one location to another.


Thanks im going to ask AHJ next week


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## Dennis Alwon (May 9, 2009)

I would call the power company. I would almost bet they wont allow a 320 amp meter for a commercial load. Depending on the type of building many loads are continuous so a 320 amp base can only have 320 amps of continuous load.

What kind of building? Most are 3 phase also.


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## morg123452000 (Nov 4, 2013)

Dennis Alwon said:


> I would call the power company. I would almost bet they wont allow a 320 amp meter for a commercial load. Depending on the type of building many loads are continuous so a 320 amp base can only have 320 amps of continuous load.
> 
> What kind of building? Most are 3 phase also.


240/120 single phase


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## Forge Boyz (Nov 7, 2014)

Dennis Alwon said:


> I would call the power company. I would almost bet they wont allow a 320 amp meter for a commercial load. Depending on the type of building many loads are continuous so a 320 amp base can only have 320 amps of continuous load.
> 
> What kind of building? Most are 3 phase also.


That is really going to depend on the power company. I can't recall if I have ever installed a 400A CT cabinet, but I have put in 320A bases on a regular basis. We can even use a 320A 3 phase meterbase for a 480V service, as long as it has a cold sequence disconnect ahead of it.

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