I have always wondered why the Code panels decided on 800 amps as the cut off point for going to the next larger Over Current device instead of 1200 amps. NEC 240.4(B)
In section 230.90 Exception 3 the two to six disconnects can have a combined rating greater than the conductors if the calculated load is less than the conductors.
If the calculated load is less than 1200 amps but, has a single disconnect then using three 500 mcm (1140 amps) is prohibited.
I don't think I have ever seen a 1,200 amp service loaded to its maximum. Most have less than 1,000 amps of load at the extreme.
Always seemed like a waste of copper to me.
