Question about single phase 320 amp wire size

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Have a 225 amp main breaker panel,2 can, 60 space total, single phase, using a 320 amp continuous load/400 amp non continuous load disconnect. Print calls for 3 4/0 in 2 1/2" c. Do I size my wire going to the disconnect off the continuous load or non continuous first off? Then use 4/0 from the disconnect to the panel. Max load is 221 amps on the panel. More details the better, Just looking for a little direction, thanks?
 

Dennis Alwon

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Chapel Hill, NC
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Have a 225 amp main breaker panel,2 can, 60 space total, single phase, using a 320 amp continuous load/400 amp non continuous load disconnect. Print calls for 3 4/0 in 2 1/2" c. Do I size my wire going to the disconnect off the continuous load or non continuous first off? Then use 4/0 from the disconnect to the panel. Max load is 221 amps on the panel. More details the better, Just looking for a little direction, thanks?

Do the prints not call this out?
 
Do the prints not call this out?
Prints do not call for the size wire or conduit from transformer to meter? 310.16 for wire size and chapter 8, 9 tables for conductor properties and pipe fill, i just kinda want to make sure im doing this right, and its for a clubhouse in case you were wondering also
 

Dennis Alwon

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Chapel Hill, NC
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I believe that the wire before the disconnect can be based on the calculated load for the building. IMO, it is probably worth just paralleling 4/0 there also in order to be appropriately sized for future loads.
 
So eventhough the total calculated load is 221 amps and the meter is a 320 continuous/400 amp non, i should still size the wire off the total calculated load eventhough it is lower than what the meter is rated for? Doesnt the wire have to be sized for the size of the meter? Obviously it will never draw the full 221 amps, but the wire isnt sized properly for the meter, correct, or am i confused?
 
320 Amp meter residential service question?

320 Amp meter residential service question?

Is it ok to feed the meter socket with 4/0 and feed the panels with 4/0 as well?
..
 

kwired

Electron manager
Location
NE Nebraska
The meter won't care if it is supplying a 10 amp load or a 320 amp load as long as conductors are sized to carry whatever the load is up to the maximum rating of the meter.

You said the main breaker was 225 amps. That is all the larger the conductors need to be sized, 4/0 is large enough.

You need to disregard the fact that the meter is rated for 320 and look at it as being rated for at least 225.

If you were installing a 150 amp service you would use a 200 amp meter base with 150 amp conductors - similar concept.
 

augie47

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Tennessee
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State Electrical Inspector (Retired)
With a single service disconnecting means the overcurrent device must be sized no larger than the conductor ampacity,
This would apply to the line and load side of the meter if the conductors are provided by the customer. If POCO supplies the line side they determine that conductor size.
 

infinity

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New Jersey
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Journeyman Electrician
So the load is 221 amps and the service disconnect is 225 amps? Seems like #4/0 is good then. The other ampacities are irrelevant.
 
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