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Subject - Residental Service 325a
Billy C I have a ? on a 325a residental service. I have been a electrician for 30 years on heavy Industerial type work. I have built my on home and I installed a 2 ton heat and AC unite for each floor, 3 units rated at 50 or 60 amps each.A friend gave me a 325a meter can, he said I would need utility pnl. and a house pnl.I cant picture a 325a residental service in my mind.If I could see a cut sheet and or a one line diagram I believe I would understand it.The house pnl is a 200a and the utility pnl ????.If you could help to picture this in my mind and understand it I could finish my design and build my service.Every thing is done on the rough in except the electrical which is my part.
Billy C Maby I should have asked it another way.How about I take the 325a meter can install double barell lugs on the load side then take 2 conduit nipels to 2 disconects 1 200a and 1 150a the 200a to feed the house pnl (lighting and rec.)then the 150a to the utility pnl.Ijust install one mast 2 1/2" or 3" with 350mcm out the weatherhead.Would this be legal by the NEC.
Billy C Maby I should have asked it another way.How about I take the 325a meter can install double barell lugs on the load side then take 2 conduit nipels to 2 disconects 1 200a and 1 150a the 200a to feed the house pnl (lighting and rec.)then the 150a to the utility pnl.Ijust install one mast 2 1/2" or 3" with 350mcm out the weatherhead.Would this be legal by the NEC. yours in new friendship Billy C
frenchelectrician before we get too far in here..

let me ask you this question about meter socket i am wondering about the 325 amp socket really it is kinda oddball one to me but what socket set up for like 400 amp interment and 320 amp countious rating ?? and is this meter socket is bolted in or push on type of socket ??

i will like to help you to clearify the mess here but if for the home yeah you can use the 320 class socket aka 325 in your area but check the poco to make sure you use that type of meter other wise they will advise ya for correct one.

for most 400 amp service it is very common to run 4/0 off from load lug[s] to each breaker box as long it have main breaker there like twin 200 amp box or 200 amp / 150 amp box or single large 400 amp box and run few subfeed boxes .

but i dont know what state you are living in there and will they allow 350kcm wire or not but i will suggst to check the local codes and the electrial inspector to see what the guideline with this type of service there.

most electrican will run a pair of 3/0 or 4/0 even 250kcm wires to each breaker box but some case can run 500 kcm wire and bug it in big junction box and branch off from there [ this is not a ideal pratice for myself for safety reason ]but let other electrican get in here and help you with it


merci , marc
JimmyDee Table 310.15(B)(6) Conductor Types and Sizes for 120/240-Volt, 3-Wire, Single-Phase Dwelling Services and Feeders

Conductor (AWG or kcmil)
Copper---Service or Feeder Rating (Amperes)
1---------------150
1/0-------------175
2/0-------------200
3/0-------------225
4/0-------------250
250-------------300
350-------------350
400-------------400
As I was thinking about this situation, I realized that 320 amp service is 80% of a 400 amp service. Are we actually talking about a 400 amp service here? I've never done a residential service this big but in a church, we installed a 400 amp disconnect (fused) and then fed the panels from there. I don't think you will find a 320 amp disconnect.
I would think (don't actually know) that you could split off the meter and feed two separate panels as long as the connected main breakers don't add up to more than the service feeder ampacity.
Jim
frenchelectrician Jim:

for 300 amps and larger service for home you can have 2 main ocpd on it for common location. but if one for house and the other to garage etc. no you cant so there is a fine line there.

i am sure Ryan can get the details here but ryan have the regualtions for state of Uath. my in state of wisconsin so the regulations might be little diffrent between us.

merci , marc
Jjohnny The power company that i work with most of the time supplies us with the meter bases. When we do a 400 amp service on a house, they provide us with a 320amp meter base. The reason being is everyone knows that 400amp is overkill for most houses. When doing a 400amp service we use 2 200 amp panels and parallel 2 4/0s. The reason for the bigger meter base is for room for the connections. The power company normally doesnt run anything bigger than 4/0 from the transformer.
Electricman The power company we deal with at times supplies 320 continuous but the sockets we use are rated 400 amps. We also do the job for another utility company that requires C T s in their meter cabinet for a 400 amp residential service. Ditto on the install posted by Jjohnny..