ok so he installs 3 15 amp breakers for conversation sake this is lower than his 70 amp feeder size, provided this is his calculated load. He would have to install a disconnect?
Or he could just install a 15A-1P spare to get his total to 60A. It would be cheaper than providing a main disconnect, but more expensive than a handle tie.He could use a MWBC and handle ties to make it a one or two circuit installation. Correct or a main breaker.
This is one area of the Code where I just scratch my head in wonder. To be a fly on the wall during CMP discussions about this one...