Journeyman Electrician Exam (NEC)Wiring Methods and MaterialsEasy
A residential electrician is installing a new 120-volt, 15-amp branch circuit for a bedroom. The circuit will use 14 AWG copper conductors. What is the minimum size equipment grounding conductor (EGC) required for this circuit?
- A14 AWG
- B10 AWG
- C16 AWG
- D12 AWG
Show answer & explanationAnswer & explanation
Correct answer: A. 14 AWG
According to NEC Table 250.122, for a circuit with an overcurrent protective device rated 15 amps, the minimum size copper equipment grounding conductor is 14 AWG. The EGC size is determined by the rating of the overcurrent device, not necessarily by the size of the circuit conductors, although it is often the same or smaller.
Why the other options are wrong
- B. Incorrect. 10 AWG would be required for a 30-amp circuit.
- C. Incorrect. 16 AWG is generally too small for a 15-amp circuit EGC.
- D. Incorrect. 12 AWG would be required for a 20-amp circuit.
EGC Sizing for Branch Circuits
The NEC requirement for determining the minimum size of the equipment grounding conductor for a branch circuit, based on the rating of its overcurrent protective device.
- Prevents dangerous voltage on non-current-carrying metal parts.
- Sized according to NEC Table 250.122.
- Must be capable of safely carrying fault current during a ground fault.
Memory trick: Overcurrent Protects, Grounding Connects.