An attic has a 120/240V, 60A service panel. A new circuit is to be added for a heating system. The branch circuit wire size must be selected based on the ampacity of the heating system. If the heating system has a maximum load of 20A, what is the minimum wire size required?
- A14 AWG
- B12 AWG
- 10 AWG
- D8 AWG
Exam tip
Always refer to the appropriate tables in the NEC for selecting the correct wire size based on the load requirements.
Why C is correct
The correct answer is 10 AWG. According to Table 310.16(B)(1) of the 2023 NEC, a 20A load requires a minimum wire size of 10 AWG. Options a, b, and d are incorrect as they do not provide the necessary ampacity for the heating system.