I know this is a "dead horse" topic, but I'm still confused about it. This subject seems to be a source of mass confusion in the electrical trade.

So, as an example, here is an a/c unit nameplate (from an 2 ton Trane unit):

Min circuit ampacity: 15 amps

Min fuse/breaker size: 20 amps

Max fuse/breaker size: 25 amps

Line running amps: 11 amps


Does this mean that the unit can be fed by #14 protected by a 20 amp breaker?

Or #12 on a 20 amp breaker?


Do you size the conductors by the "minimum ampacity," and size the breaker by "minimum fuse/breaker"? [Linked Image]

One thing I do understand is that in this situation, the breaker only provides short-circuit protection, as the motor is protected by a thermal overload device.
-Peter

Peter