I have never understood why a building official would want to adopt a code to require a higher rating of a circuit then what is allowed per NEC?
heres how I feel, with the many cheap cords and wiring in appliances we get these days, and the fact that many older appliances are still in use, and cords that unknowingly get replaced on appliances can be a hazard when plugged into circuits with a higher rating, I have seen Christmas lights with very small wire I.E. 22 awg or smaller that have no chance to trip a 20 amp circuit, but would a 15 amp circuit, so why in the world would they make a code to only allow 20 amp circuits, what are they thinking?
I have had home owners want all 20 amp circuits in a house, and after I tell them there increasing the possibility of having a fire with using older appliances with possible bad cords and or using these cheap Christmas lights that come from over seas, they change their mind real quick, I guess after a neighbor who had a fire because his cat chewed into the cord from his lights on his Christmas tree and the wire just glowed red hot instead of tripping the 20 amp breaker that it was plugged into, I changed my thinking, before this I was one who thought bigger was better.
I know that most equipment today is required to have at the minimum 20 AWG cords, which will trip a 20 amp breaker on a bolted fault, but add any resistance or voltage drop to the circuit such as an extension cord and you could just get to a point a 20 amp breaker wont open, and sure the same could be true with a 15 amp breaker, but I think I would rather have the 15 amp breaker to at least lessen the possibility?
I'm glad that here our state followed this reasoning also when it was suggested to require all circuits to be 20 amps in a house.
so for me its 15 amps for any general purpose receptacles, more breakers/circuits if they want, but not 20 amp circuits.