Time out!!
The OP clamped a leg and got 70 amps! He does not remember the Peak KW demand from the POCO, but it was 'low'.
The 800 amp service is probably overkill.
I clamped my 150A panel and measured 3A per phase. NEC calculations say I'm supposed to have a 200A service. The pole pig feeding the whole block is only 25kVA (104A). Do you think I should trust that 3A is my typical load, and put in a 10A service disconnect and a 10A ATS?
My point is that this is a HUGE house, and I doubt they put in an 800A service for the heck of it. NEC calcs take all the loads into account and tell you what your max loads
could be, and the size of the service shouldn't be changed unless it be proven via calculation to actually be overkill. It's a very reasonable size for a house with electric heat, though.
