Journeyman Electrician Exam (NEC)Services, Feeders, and Branch CircuitsEasy
A client requests a 120-volt, 20-ampere branch circuit for general-purpose receptacles in a dwelling unit. What is the minimum size copper equipment grounding conductor (EGC) required for this circuit?
- ANo. 12 AWG
- BNo. 8 AWG
- CNo. 14 AWG
- DNo. 10 AWG
Show answer & explanationAnswer & explanation
Correct answer: A. No. 12 AWG
According to NEC Table 250.122, for an overcurrent protective device of 20 amperes or less, the minimum size copper equipment grounding conductor is No. 12 AWG.
Why the other options are wrong
- B. No. 8 AWG is significantly larger than required for a 20-ampere circuit.
- C. No. 14 AWG is typically used for 15-ampere circuits, not 20-ampere circuits.
- D. No. 10 AWG is larger than required for a 20-ampere circuit.
EGC Sizing (Branch Circuit)
The minimum size of an equipment grounding conductor (EGC) for a branch circuit is determined by the rating of the overcurrent protective device, as specified in NEC Table 250.122.
- NEC Table 250.122 is used for sizing EGCs.
- EGC size is based on the overcurrent device, not the load.
- Copper is the most common material for EGCs.
Memory trick: EGC size matches the overcurrent protector's punch.