Aldav,
If you go to the "Home Depot Pro", at the NW corner of Thomas and 32nd street.
In there they have 400amp all-in-ones for Square D and Cuttler Hammer.
That store is made for contractors like yourself.
About $800.00 each.
Like one of the posts said. It has two 200amp breakers. One feeds the 40 space panel built inside and the other 200-amp breaker will feed a remote panel.
The only thing that sucks is that the existing Underground PVC pipe, comming from the transformer, will be to small for SRP to pull in bigger feeders. In order to run a bigger PVC conduit, say 3" or 4", you usually have to saw cut the driveway.
I usually try to make the existing 200-amp panel work. Install a 100-amp sub panel like you said.
Good luck.
Tev
