320A meter base - panel sizes

[jeff48356]

If I install a 320A meter base (with service conductors rated for such), would I be allowed to install two 200A panels in the basement, or would one of them need to be a 100A (or 150A)?

Since 2/0 copper (or 4/0 aluminum) is used for 200A service per the 83% rule, what would be the sizes of CU and AL conductors to be used to feed a 320A? Just wondering since 200A is the largest I've ever installed.

 

[Dennis Alwon]

A 320 amp meter base is really a 400 amp base non continuous. The 320 is for continuous loads (400x .80= 320).

So yes 2- 200 amp panels are allowed. However, since neither panel feeds 100% of the dwelling load then you cannot use the 83%. You would need to use the tables of 310.15(B)(16)

4/0 could be used if you are not over 180 amps calculated load in either panel. I assume you can take advantage of the 75C column for either pipe of SE cable.

 

[jeff48356]

A 320 amp meter base is really a 400 amp base non continuous. The 320 is for continuous loads (400x .80= 320).

So yes 2- 200 amp panels are allowed. However, since neither panel feeds 100% of the dwelling load then you cannot use the 83%. You would need to use the tables of 310.15(B)(16)

4/0 could be used if you are not over 180 amps calculated load in either panel. I assume you can take advantage of the 75C column for either pipe of SE cable.

OK, so I would probably use 3/0 THHN copper for the feeds to each panel (2/0 for neutral). What size conductors on the line side from the POCO would most likely be used?

 

[Dennis Alwon]

OK, so I would probably use 3/0 THHN copper for the feeds to each panel (2/0 for neutral). What size conductors on the line side from the POCO would most likely be used?

Are you running the line side of the meter? Power company usually does that

 

[jeff48356]

Are you running the line side of the meter? Power company usually does that

No, the POCO would run that. Since it would need to be rated for 320A, I was thinking they might use 350 kcmil CU or 500 AL.

 

[ptonsparky]

No, the POCO would run that. Since it would need to be rated for 320A, I was thinking they might use 350 kcmil CU or 500 AL.

Feel lucky if you get 4/0 Al. Maybe 250, but don’t loose sleep over either.

 

[kec]

Are you running the line side of the meter? Power company usually does that

Here in CT we have a smaller POCO that covers a county that requires we supply the underground service wire. They will assist in pulling conductors in conduit.
I will provide 350 MCM Al for a 320 meter.

 

[kwired]

OK, so I would probably use 3/0 THHN copper for the feeds to each panel (2/0 for neutral). What size conductors on the line side from the POCO would most likely be used?

Since you have multiple service disconnecting means, NEC only requires you to run conductors with enough ampacity to carry the calculated load.

As mentioned with some POCO's, 4/0 aluminum may be what you get. Quite a few probably would pull 350 aluminum to this though.