A bathroom’s 20-ampere branch circuit will use copper conductors with 60°C terminations at 30°C ambient temperature. No ampacity adjustment, correction or special exception applies. The load does not require a conductor ampacity above 20 amperes. Under 2023 NEC 240.4(D), what is the minimum conductor size?

ICC E1 exam practice question · Branch Circuit & Feeder Requirements

A bathroom’s 20-ampere branch circuit will use copper conductors with 60°C terminations at 30°C ambient temperature. No ampacity adjustment, correction or special exception applies. The load does not require a conductor ampacity above 20 amperes. Under 2023 NEC 240.4(D), what is the minimum conductor size?

A14 AWG
12 AWG
C10 AWG
D8 AWG

Where to look it up

https://codes.iccsafe.org/content/PHXRC2024P1/chapter-37-branch-circuit-and-feeder-requirements

Why B is correct

12 AWG copper has 20-ampere ampacity in the 60°C column and a 20-ampere small-conductor protection limit. The corresponding limit for 14 AWG copper is 15 amperes. Source: ICC official 2024 IRC, unchanged provisions reproduced in the Phoenix adopted edition. https://codes.iccsafe.org/content/PHXRC2024P1/chapter-37-branch-circuit-and-feeder-requirements

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