440.4(B) Air-Conditioning, Circuit Sizing – https://www.MikeHolt.com/code. The first time you’re called upon to size a conductor and overcurrent device for central air-conditioning and you look at the nameplate requirements that clearly state that a 10 AWG copper conductor and a 50A OCPD are required, it may contradict everything you’ve learned about small conductors. In fact, you may adamantly insist that 6 AWG is required by the Code and you’d be wrong! Learn why in this podcast on section 440.4(B) of the NEC.