I think the intent of 230-40 Exception 1, is to allow for different types of services, e.g., 120/208 3phase, 120/240 1 phase, for building with one or more occupancies. But I do admit it can be read many ways. I wonder what the purpose of saying ...to each occupancy or group of occupancies.
I think the building should have a main outside. After all the reason for the main is to let the firemen go into the building, in the event of a fire, without a risk of electrocution.
A building with common areas does not allow this without a main outside.
Does someone have a definition of occupancy as the NEC uses it?
