A customer has a 3500 sq ft home and wants to upgrade his 200 amp 1Ph panel because it is full and he wants to add a 240v 50a spa, a 240v 20a waterfall and a 500 sq ft guest house with elec heat, kitchen etc. If I do this the power co will have to pull in new feeders from the transformer and I'll have to use 2 - 200 amp panels. One main 200 amp panel feeding another 200 amp load center. (As far as I know they don't make a all-in one 400 amp panel). These are outdoor panels which are mostly used here in AZ. Cost is around $1000 just for the parts. Option 2: is possibly adding a 100 amp sub panel off the exhisting 200 amp panel, (having to make room for the 100a feeder breaker), this would be less expensive. I'm going to amp clamp the load, also will figure the total load service calculation from the back of the code book. Any suggestions, comments, or ideas on this? Thanks,
The Golden Rule - "The man with the gold makes the rule"
All of the big manufactures (GE, Square D, Cutler-Hammer, Siemens, Etc.) make 400 amp combination service entrance devices. You can get them with a single 400 amp breaker feeding the internal 40 circuit loadcenter or with 2-200 amp breakers, 1 feeding the internal loadcenter and the second to feed a remote panel. Square D only make one with the 2-200 amp breakers but I know GE and Cutler-Hammer makes both styles. If you need some part numbers let me know.
what type heat does the main house have. that is my rule of thumb guide to service sizes, along with sq footage. if they have gas, i'd probably use the existing service. if they have heat pumps, they're probably stretched thin already. either way heres a real time saver for figuring the load: http://www.vickrey-s.com/SFDLoadCalc.asp
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.