jar546
CBO
I understand that NEC 310.12(B) allows for the reduction in size of feeder conductors when they supply the entire load of a one-family dwelling, by permitting an ampacity of not less than 83% of the feeder rating. However, I'm struggling to see practical scenarios where this reduction makes sense. For example, if I have a feeder that comes from a combo panel located outside a home, with the combo panel serving as the service disconnect and meter combo, and this feeder comes into the garage to the main panel for the house, which serves 100% of the dwelling unit's load, it is code compliant. But if I install a circuit for an AC condenser unit originating from the combo panel, the feeder size cannot be reduced because it no longer serves 100% of the dwelling. This does not make sense to me.