Apartment buildings can vary on incoming service based on when they were built. Newer ones are 277/480 or 120/208 as they are commercial. Older ones are 120/240 delta....I truly dislike the wild leg!
All single family homes around here are 120/240 services.
It was mentioned 480Y/277 + 208Y/120 with transformer or TWO SERVICES.
Why would you bring in 480v?
Central chiller on roof or basement that provides cooling for all the building or buildings in complex. Running 4 fast elevators serving 40 stories. Parking facility lighting.
That is not an apartment building it is a hotel where the guests stay for long time - even years:lol:
Seriously I can see the need to bring 277/480 into the building if it is a rather large building and especially if it has elevators, fire pump, centralized heating or cooling, and things like that.
I don't see much need for a 240 delta for apartment building. What are you going to use the wild leg for besides HVAC? Maybe in a rather large facility but then 277/480 again would likely make more sense.