Most of our work is with 400 amp services. You use 2 - 200 amp panels and either a meter disco combo with 2 -200 mains in it or we build a service using a 320A meter base and 2 - 200 amp disco's. It depends on whether the poco in the area will give us the meter base for free or if we have to buy it from them. If they charge, we just put that money (usually about $180) towards the cost of the combo unit and save the labor time.
#43337 - 10/11/0409:45 AMRe: 400 AMP 1PH RESIDENTIAL SERVICE
Just installed one the other day! One of our projects is an upper end survey of fine million dollar plus homes and half will have the 400A service. The Hydro company wants us to use an outdoor meter with built in CTs (Microlectric brand), from there we bring the service to the main switch and add a splitter. We normally put a 200A panel near the main service, and add 100A subpanels as needed off the splitter throughout the residence (usually top floor, kitchen, and near the backyard for the pool equip, hot tub, etc.)
#43338 - 10/11/0408:07 PMRe: 400 AMP 1PH RESIDENTIAL SERVICE
That's is pretty much how I was doing it until lately. I found a Murray panel that has a double main break in it. A 400 amp bus which the line lugs goes directly to a factory installed 200 amp breaker with provisions on the line bus for a second 200 amp breaker. So in essense you have up to 70 circuits on one 400 amp service because you can add a 40 ckt MLO. Also your allowed an additional 125 amp breaker in this 400 amp panel for an additional MLO. This is allowed with the use of a regular 400 amp 4 jaw meter socket. Milbank makes the U2448-x model socket. In the long run you save quite a bit as long as it's allowed in you areas.