# 320 amp service cable size



## I Conduit

I'm a commercial electrician, never did a 320 amp service. My neighbor wants to upgrade his resi service to a 320 with two 200 amp panels. My questions are: (2008 code cycle)

does a 320 meter socket come with parallel lugs?

Do I use t310.15(b)(6) or t310.16 for cable size to each panel?


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## Dennis Alwon

I Conduit said:


> I'm a commercial electrician, never did a 320 amp service. My neighbor wants to upgrade his resi service to a 320 with two 200 amp panels. My questions are: (2008 code cycle)
> 
> does a 320 meter socket come with parallel lugs?
> 
> Do I use t310.15(b)(6) or t310.16 for cable size to each panel?


Firstly, lets get the terminology straight because it is confusing. A 200 amp service has a 200 amp meter base that is rated 160 amps for continuous load but rated 200 amps for non-continuous loads. A 400 amp meter base is rated 400 amps non- continuous loads and 320 amps (80%) for continuous loads.

So the service you are installing is a 400 amp service and I don't know why they call the meter 320 amps instead of 400 amps. Why do they use continuous load rating on the 400 and the non continuous load rating for the 200 amp meter. It is confusing.

Okay now the meters do come with double lugs or you can buy a combo meter panel that has the meter and the the 2- 200amp breakers already installed as one unit.

Now the question about T. 310.15(b)(6) is one that is debated much on the forums. My opinion is that T. 310.16 must be used in this case since T. 310.15(B)(6) does not state anything about a 400 amp service being used with 2-200 amp panels. I would check with your AHJ-- some are still allowing T.310.15(B)(6) to be used.


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## I Conduit

Dennis Alwon said:


> Firstly, lets get the terminology straight because it is confusing. A 200 amp service has a 200 amp meter base that is rated 160 amps for continuous load but rated 200 amps for non-continuous loads. A 400 amp meter base is rated 400 amps non- continuous loads and 320 amps (80%) for continuous loads.
> 
> So the service you are installing is a 400 amp service and I don't know why they call the meter 320 amps instead of 400 amps. Why do they use continuous load rating on the 400 and the non continuous load rating for the 200 amp meter. It is confusing.
> 
> Okay now the meters do come with double lugs or you can buy a combo meter panel that has the meter and the the 2- 200amp breakers already installed as one unit.
> 
> Now the question about T. 310.15(b)(6) is one that is debated much on the forums. My opinion is that T. 310.16 must be used in this case since T. 310.15(B)(6) does not state anything about a 400 amp service being used with 2-200 amp panels. I would check with your AHJ-- some are still allowing T.310.15(B)(6) to be used.


Thanks for your very informative and timely response. I think I will go with your advice and use table 310.16, that avoids any issues with the AHJ. I will be giving my neighbor a nice discount on labor (it's a side job) so to spend a little more for cable is not going to be a big deal.


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## brian john

It is tidbits like Denni's post that make this site more than worth the yearly membership fee's.:whistling2:

Seriously very nice Dennis, I always wondered about the 320 amp Meter can.


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## Magnettica

Yeah, but he probably just copied and pasted it from some other site. :lol: Just kidding Dennis!

Is this underground or overhead?


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## B4T

There is such a MP here that is rated for 320 amp.

It can only be used for (2) 150 amp panels.. some other places will allow (2) 200 amp. panels for a 320 service


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## Dennis Alwon

Black4Truck said:


> There is such a MP here that is rated for 320 amp.
> 
> It can only be used for (2) 150 amp panels.. some other places will allow (2) 200 amp. panels for a 320 service


I doubt it. Are you sure that is not just the ignorance of the inspectors talking?


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## B4T

Dennis Alwon said:


> I doubt it. Are you sure that is not just the ignorance of the inspectors talking?


I just did a service a year ago using the 320 MP. with (2) 150 panels and both POCO and inspector signed off on it.

They are a common item here.. half the size of a 400a MP and half the cost


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## NolaTigaBait

Black4Truck said:


> I just did a service a year ago using the 320 MP. with (2) 150 panels and both POCO and inspector signed off on it.
> 
> They are a common item here.. half the size of a 400a MP and half the cost


Don't think he' saying its wrong, he's saying you could put 2 200's on that pan is what I'm saying:jester:


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## Bob Badger

Black4Truck said:


> There is such a MP here that is rated for 320 amp.
> 
> It can only be used for (2) 150 amp panels.. some other places will allow (2) 200 amp. panels for a 320 service


I am going with 'doubt it' also. I think you have been lied too. :laughing:

Seriously, read the tag carefully. 

Maybe your power company may restrict it to that, or your inspectors are misinformed but a 320 class meter is rated 320 continuous and 400 amp non-continuous.

The combined capacity of two 200 amp 'standard' load centers are also rated 320 amp continuous and 400 amp non-continuous.

On the other hand the combined capacity of two 150 amp panels is only 240 amp continuous and 300 amp non-continuous.


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## Dennis Alwon

Black4Truck said:


> I just did a service a year ago using the 320 MP. with (2) 150 panels and both POCO and inspector signed off on it.
> 
> They are a common item here.. half the size of a 400a MP and half the cost


I am sorry -- I am surprised it would be called a 320amp meter pan. It doesn't make sense since 320 amp is not a standard service size. Now if you said there is a 300 amp MP that would make sense.




Brian John said:


> It is tidbits like Denni's post that make this site more than worth the yearly membership fee's.:whistling2:
> 
> Seriously very nice Dennis, I always wondered about the 320 amp Meter can.


Thanks Brian


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## B4T

I call it a 300A MP when I order it from supply house.. only on these forums is it called 320A :blink:


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## NolaTigaBait

Black4Truck said:


> I call it a 300A MP when I order it from supply house.. only on these forums is it called 320A :blink:


Cool, I call it a 400 amp meter pan. I'm better than you:thumbsup:


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## Dennis Alwon

Black4Truck said:


> I call it a 300A MP when I order it from supply house.. only on these forums is it called 320A :blink:


We are probably talking about 2 different animals. When I order a service for 400 amps I ask for a 400 amp meter base and I get a base that is marked 320 amps. It is rated 400 amps noncontinuous so it works well for a 400 amp service. The question is why they use 320 amps instead of the 400 amp nomenclature.


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## B4T

NolaTigaBait said:


> Cool, I call it a 400 amp meter pan. I'm better than you:thumbsup:


 
Not a 400.. does not use CT's.. why so much cheaper in price :thumbsup:


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## NolaTigaBait

Black4Truck said:


> Not a 400.. does not use CT's.. why so much cheaper in price :thumbsup:


Says you:thumbsup:


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## Dennis Alwon

Black4Truck said:


> Not a 400.. does not use CT's.. why so much cheaper in price :thumbsup:


The 400 amp meter bases we use do not have CT's either.


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## NolaTigaBait

Dennis Alwon said:


> We are probably talking about 2 different animals. When I order a service for 400 amps I ask for a 400 amp meter base and I get a base that is marked 320 amps. It is rated 400 amps noncontinuous so it works well for a 400 amp service. The question is why they use 320 amps instead of the 400 amp nomenclature.


Right, on the milbanks site it calls it a 320 amp base.


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## Magnettica

Black4Truck said:


> I just did a service a year ago using the 320 MP. with (2) 150 panels and both POCO and inspector signed off on it.
> 
> They are a common item here.. half the size of a 400a MP and half the cost



The cost..... my most common power company to deal with is PSEG, and if I have an approved permit for a service upgrade for a single family or 2-family, the meter is free. All I have to do is go pick it up. :thumbsup:


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## B4T

Page 8 is a pic of a 300A MP

http://www.milbankmfg.com/products/Catalogs/CatalogFiles/PDF/LIPA_NationalGrid.pdf


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## NolaTigaBait

That's the one I'm talking about. It says 320 right on top the page. Everybody calls it something different based on where you live I guess.


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## B4T

Top of page says 400A rated.. bottom of page says check with POCO.

They won't accept (2) 200 amp. panel with that MP :no:


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## Magnettica

Black4Truck said:


> Page 8 is a pic of a 300A MP
> 
> http://www.milbankmfg.com/products/Catalogs/CatalogFiles/PDF/LIPA_NationalGrid.pdf


Your POCO measures it's neutral current too?

I thought only pseg did that.


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## NolaTigaBait

Black4Truck said:


> Top of page says 400A rated.. bottom of page says check with POCO.
> 
> They won't accept (2) 200 amp. panel with that MP :no:


I'm not questioning you, I just don't understand. As the Badger stated, that pan is rated for 320 continuous and 400 overall. Each 200 amp panel is rated 160 continuous and 200 overall. I guess dealing with a POco is like dealing with local government, no one knows why and no one really cares.


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## B4T

Magnettica said:


> Your POCO measures it's neutral current too?
> 
> I thought only pseg did that.


I never noticed that before.. got to ask a POCO worker.

Sometimes things are there, but not being used


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## Magnettica

Black4Truck said:


> I never noticed that before.. got to ask a POCO worker.
> 
> Sometimes things are there, but not being used


We call it the 5th jaw. A few years ago I was wiring a 4-gang meter stack and I never heard of it either at that point and my boss told me to go install the 5th jaw. I had no idea WTH he was talking about either :no:


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## NolaTigaBait

Magnettica said:


> We call it the 5th jaw. A few years ago I was wiring a 4-gang meter stack and I never heard of it either at that point and my boss told me to go install the 5th jaw. I had no idea WTH he was talking about either :no:


The French Quarter has the 5th jaw deal on their meters also.


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## B4T

NolaTigaBait said:


> I'm not questioning you, I just don't understand. As the Badger stated, that pan is rated for 320 continuous and 400 overall. Each 200 amp panel is rated 160 continuous and 200 overall. I guess dealing with a POco is like dealing with local government, no one knows why and no one really cares.


It was brought up to the POCO suits and they could not give a clear reason why it's not excepted. 

They don't like the spotlight very much :laughing:


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## Dennis Alwon

Black4Truck said:


> It was brought up to the POCO suits and they could not give a clear reason why it's not excepted.
> 
> They don't like the spotlight very much :laughing:


What Poco requires is very different then what is given. At first you said you had a 320 MB that could only have 300 amps. This may be true because of the Poco requirements but not true based on the listing of the equipment. There was much confusion but I think we are all clear now.


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