Master Electrician Exam (NEC)Services, Feeders, and Branch CircuitsEasy
A master electrician is installing a new 200A, 120/240V single-phase service for a dwelling unit. The service entrance conductors are 3/0 AWG copper. What is the minimum size copper equipment grounding conductor required for the service?
- A2 AWG
- B8 AWG
- C6 AWG
- D4 AWG
Show answer & explanationAnswer & explanation
Correct answer: C. 6 AWG
According to NEC Table 250.122, for a 200-ampere overcurrent device, the minimum size copper equipment grounding conductor is 6 AWG.
Why the other options are wrong
- A. 2 AWG is significantly larger than required and not the minimum size.
- B. 8 AWG is too small for a 200A service per NEC Table 250.122.
- D. 4 AWG is larger than required, but not the minimum size.
Equipment Grounding Conductor Sizing
The process of determining the minimum size of the equipment grounding conductor based on the rating of the overcurrent protective device.
- Sized according to NEC Table 250.122.
- Protects equipment from ground faults.
- Must be capable of carrying fault current until the overcurrent device trips.
Memory trick: Grounding conductors are like safety belts; size them right for the ride.