Journeyman Electrician Exam (NEC)Special Occupancies, Equipment, and ConditionsMedium
A solar photovoltaic (PV) array is installed on a residential rooftop. The array consists of multiple modules connected in series and parallel. What is the minimum required size for the equipment grounding conductor (EGC) for a PV array circuit that has an overcurrent protective device rated at 40 amperes, if the conductors are copper?
- A4 AWG copper
- B6 AWG copper
- C8 AWG copper
- D10 AWG copper
Show answer & explanationAnswer & explanation
Correct answer: D. 10 AWG copper
According to NEC Table 250.122, for an overcurrent protective device rated at 40 amperes, the minimum size for a copper equipment grounding conductor is 10 AWG. This table is used to size EGCs based on the rating of the overcurrent device.
Why the other options are wrong
- A. This size is much larger than necessary and is not compliant as a minimum for a 40 A OCPD.
- B. This size is significantly larger than required, leading to unnecessary cost.
- C. This size is larger than required for a 40 A OCPD.
PV EGC Sizing (NEC)
The determination of the minimum cross-sectional area for the equipment grounding conductor in a photovoltaic system based on the rating of the associated overcurrent protective device, as per NEC Table 250.122.
- Based on the overcurrent protective device rating.
- Ensures safe fault current path.
- Refer to NEC Table 250.122 for sizing.
Memory trick: Grounding conductor size: OCPD rating is the guide, Table 250.122 is where to confide.