Without cracking the book, I know that a single family dwelling requires a minimum of 100 amps, 120/240 three wire.
Apartments (multi-family) dwelling units (NOT Townhouses) have no 'Minimum' that I am aware of. It's done on calculated loads for the unit.
You should check with your local AHJ to see if there are any requirements; or perhaps one of the CA members can provide that info.
Remember I'm in New Jersey!
