james cohee said:
what is most efficient way to connect 400 mcm to 200 amp panel and breakers?
There are a few ways to do this.
If you want to stay with residential load centers I would buy a large enough can at least 18" x 18" X 6" plan on that going near the floor under the panel location, the 4" conduits would come in and out the bottom. Then run a 2" up to the panel.
To splice the 400s and 3/0 going to the panel you could use something like an Ilsco PBTS-3-500
The model number I posted will handle 3 conductor from 500 down to 4 AWG in and combination.
Or you could use a power distribution block,
You could get one for your combination from Ilsco, Bussman, Burndy, Ferraz Shawmut etc.
is there a 200 amp panel that accepts 4" conduit on the bottom? breakers?
Sure, you could get a commercial tub, generally 7.5" Deep, 20" wide and as tall as you want.
You could get the tub and panel board with a 200 amp main breaker that would accept 400 Kcmil in and feed threw lugs for the out going 400 Kcmil doing away with the splice box I mentioned above.
But that could be a very expensive purchase if your not normally buying that type of a equipment.
Keep in mind (if you don't know already) that commercial panel boards are sold in pieces.
The enclosure (Tub in my area)
The dead front and interior (The bus-bars)
The panel cover (Flush, surface, with door, without door, hinge on hinge)
Many time a local panel shop will assembly the interior to the job specifications