ECN Forum Forums Code Related Discussion NEC & other Code issues Sizing of service lateral from 320 Amp meter base?

Can anybody tell me how to size the service cable from the feed through meter to two 200-amp panels at a residence. I am removing the existing CT's and meter because an addition will put the meter inside of the house. They are also going to a heat pump and removing the circuits for the electric ceiling heat for a house that is about 3000 square feet. So the load will be reduced at least 50%. The service calculates at about 140 amps max. I am planning on leaving both of the existing 200-amp panels which will be fed from this service lateral. Thanks for your help guys!

Common install here (NJ) is 200 amp SEU cable (4/0 al-2 insulated, 1 bare) to each 200 amp MCB panel. Provided that panels are within acceptable distance. Option would be conduit & 4/0 al conductors.

I'm assuming that you are talking about the 'load' side of the meter, and the disconnects are in each panel?

John

4/0 SEU (AL) or 2/0 SEU (CU) to each panel is the norm here in Virginia as well. We are lucky, the power company handles all final connections at the meter, so all we have to do is mount the meter socket and bring the cables into it. They do the rest.

Thanks for your input, guys. I have a single 3" conduit, so I did some research in section 230 on service ampacity. As long as the computed load is less than the service ampacity, the cable can have a smaller ampacity than the overcurrent rating of the service. I didn't want to run parallel cables from the 320-amp meter to each panel. It looks like 350-alum will be plenty big for the two panels. It will splice in the old CT cabinet. (The CT's are going away). Thanks again for your replies!