Journeyman Electrician Exam (NEC)Grounding and BondingEasy
A residential electrician is installing a new 100-ampere service. The grounding electrode conductor (GEC) is connected to a single ground rod. What is the minimum size for this GEC, assuming the service entrance conductors are 3 AWG copper?
- A8 AWG copper
- B2 AWG copper
- C4 AWG copper
- D6 AWG copper
Show answer & explanationAnswer & explanation
Correct answer: D. 6 AWG copper
According to NEC Section 250.66(A), a grounding electrode conductor connected to a single rod, pipe, or plate electrode does not need to be larger than 6 AWG copper. The service entrance conductor size does not dictate a larger GEC in this specific scenario for a single rod.
Why the other options are wrong
- A. This is too small for a grounding electrode conductor to a ground rod.
- B. This size is significantly larger than required for a single ground rod electrode.
- C. This size is larger than required by code for a single ground rod electrode.
GEC Sizing to Rod Electrode
The minimum size of a grounding electrode conductor connected to a single rod, pipe, or plate electrode, as per NEC 250.66(A).
- Applies to single rod, pipe, or plate electrodes.
- Minimum size is 6 AWG copper.
- Not dependent on service entrance conductor size in this specific case.
Memory trick: Rod's GEC: Six is the fix!