What size riser is needed for 320/400 overhead metercan?

[rt66electric]

Well crap.. can't find code book (loaned it to sombody??)

A residential customer needs a upgrade to a 320/400 overhead metercan and dual 200 amp breaker boxes.

What size riser pipe (3in grc?)

What size copper wire(350mcm or 500mcm ??).

The serviceman from POCO could not answer.

loads severed are... all electric large house

(2) heatpumps w/elect backupstrips

(2) hot water tanks

stove,dryer, etc

above ground pool
detached machine shop mill, lathe (rotary converter)

Old POCO transformer blew up on a cold 5 deg night...Later smoked the service entrance splices, etc etc

 

[Dennis Alwon]

500 kcm copper is good for 380 amps so if your load doesn't exceed that you can go with it

 

[augie47]

Sounds like an ideal candidate for a load calculation. Your "400" sounds a lot like a "guess" and may lead to another meltdown.
a 400 kcmil would be allowed on a 400 amp residential service but with your shop equipment and bevy of other electrical I wouldn't encourage the minimum. Mike has a fairly easy to use load calculator in his "Free Stuff" on the home site.

 

[kwired]

With more than one service disconnect, this is only required at minimum to be able to carry the calculated load.

Even though you have 2-200 amp mains, legally this conductor could be 150 amp conductor if the load calculation is only 150 amps. 320/400 amp meter and mains is kind of overkill if that is the situation though, usually there is a need for more than 200 amps if choosing to use such gear.

Otherwise since it is a dwelling and 310.15(B)(7) can be used it would need to be 400 copper to get full 400 amp rating out of it, should be able to parallel 2/0 copper also, but would need make ampacity corrections if all in same raceway.