Trick first off 14 AWG is rated anywhere from 20 to 25 amps depending on the insulation and terminations.
On typical branch circuits 240.4(D) requires us to use a 15 amp over current device.
However for HVAC units 240.4(G) applies and we can use 14 AWG up to the rating in 310.16 and the short circuit and ground fault protection can be as allowed in 440.6
Bob Badger Construction & Maintenance Electrician Massachusetts
