# apartment service wire question



## farm (Oct 1, 2014)

I have a 1200amp 3ph 120/208v switch feeding a bank of 29 single phase meter centers at an apartment complex. The individual apartments have 125amp main breaker load centers. What size ser cable? Size per 310.15 for dwelling services even though the voltage coming in is 120/208v three phase but, the individual pats are single phase?

I have 2/0 aluminum wire for the project.


Thanks, Mark


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## Black Dog (Oct 16, 2011)

farm said:


> I have a 1200amp 3ph 120/208v switch feeding a bank of 29 single phase meter centers at an apartment complex. The individual apartments have 125amp main breaker load centers. What size ser cable? Size per 310.15 for dwelling services even though the voltage coming in is 120/208v three phase but, the individual pats are single phase?
> 
> I have 2/0 aluminum wire for the project.
> 
> ...


The voltage does not matter and 1/0 AL would be fine.

Welcome aboard.:thumbsup:


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## aftershockews (Dec 22, 2012)

Black Dog said:


> The voltage does not matter and 1/0 AL would be fine.
> 
> Welcome aboard.:thumbsup:


1/0 for 1200 amp service? Or is this for the 125 amp feeders?


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## bkmichael65 (Mar 25, 2013)

Black Dog said:


> The voltage does not matter and 1/0 AL would be fine.
> 
> Welcome aboard.:thumbsup:


1/0 AL ser is only good for 100 amps. 1/0 CU would be good for 125 amps


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## backstay (Feb 3, 2011)

bkmichael65 said:


> 1/0 AL ser is only good for 100 amps. 1/0 CU would be good for 125 amps


I think if you read 310.15(B)(7) you will find 1/0 is ok for 125 amps.


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## bkmichael65 (Mar 25, 2013)

backstay said:


> I think if you read 310.15(B)(7) you will find 1/0 is ok for 125 amps.


You're right. For some reason I missed that these were feeding apartments


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## don_resqcapt19 (Jul 18, 2010)

backstay said:


> I think if you read 310.15(B)(7) you will find 1/0 is ok for 125 amps.


That section does not apply as the system is not a 120/240 volt, 3 wire single phase system. 

You are not permitted to use the reduced conductor sizes for a single phase 120/208 volt system as being asked about in this thread.


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## Going_Commando (Oct 1, 2011)

don_resqcapt19 said:


> That section does not apply as the system is not a 120/240 volt, 3 wire single phase system.
> 
> You are not permitted to use the reduced conductor sizes for a single phase 120/208 volt system as being asked about in this thread.


This man knows of what he speaks. 2/0 AL is the correct choice for said installation.


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## farm (Oct 1, 2014)

for the 125amp apartment panels. I have 2/0 ser.


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## davidy (Oct 23, 2014)

i wouldnt use alluminum period


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## niteshift (Nov 21, 2007)

Wouldn't it be 2/0 *SER* for the 29 apt. panels?


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## aftershockews (Dec 22, 2012)

Are we looking for the correct wire size for the service or is it for the individual feeders?


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## farm (Oct 1, 2014)

From meter bank to each apt panel


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## aftershockews (Dec 22, 2012)

farm said:


> From meter bank to each apt panel


Ok, then #2 thhn cu and your good.


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## Rochsolid (Aug 9, 2012)

davidy said:


> i wouldnt use alluminum period


Why is that? All we use is Aluminum feeders for our larger projects. Current project we just pulled 1000 mcm Al.


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## niteshift (Nov 21, 2007)

farm said:


> for the 125amp apartment panels. I have 2/0 ser.


My bad, didn't notice you already said SER.


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