mathcoin
Member
- Location
- California
- Occupation
- Electrical Engineering
Dear all,
I am installing an AC unit with a minimum circuit ampcity of 17.9 A, and a max fuse size of 25 A. I am installing a dedicated branch using 1/2" EMT and 12 AWG THHN-THWN-2. The ac unit is connected to a fused disconnect box with 25 A fuses. My question is if a 30 amp breaker (cannot find a 25 A GFCI) is okay for this branch or would I need to switch to 10 AWG THHN? I know 240.4(D) says 12 AWG is limited to 20 A, but NEC 310.16 says 12 AWG THHN has a 30 A ampcity. I am also aware since NEC 240.4(G) points to NEC 440 for AC units which may overrule 240.4(D). Thank you for the help.
I am installing an AC unit with a minimum circuit ampcity of 17.9 A, and a max fuse size of 25 A. I am installing a dedicated branch using 1/2" EMT and 12 AWG THHN-THWN-2. The ac unit is connected to a fused disconnect box with 25 A fuses. My question is if a 30 amp breaker (cannot find a 25 A GFCI) is okay for this branch or would I need to switch to 10 AWG THHN? I know 240.4(D) says 12 AWG is limited to 20 A, but NEC 310.16 says 12 AWG THHN has a 30 A ampcity. I am also aware since NEC 240.4(G) points to NEC 440 for AC units which may overrule 240.4(D). Thank you for the help.