CSLB C-46 Solar ContractorElectrical and Plumbing CodesMedium
A solar contractor is installing a ground-mounted PV array on a commercial property. The metallic support structure for the array is required to be bonded. According to the National Electrical Code (NEC), what is the minimum size of the equipment grounding conductor (EGC) for the PV array structure if the PV system's maximum overcurrent protective device (OCPD) is 100 amperes?
- A8 AWG copper
- B6 AWG copper
- C2 AWG copper
- D4 AWG copper
Show answer & explanationAnswer & explanation
Correct answer: B. 6 AWG copper
According to NEC Table 250.122, for an overcurrent protective device rating of 100 amperes, the minimum size for the equipment grounding conductor (EGC) is 6 AWG copper. This ensures adequate fault current path for safety.
Why the other options are wrong
- A. 8 AWG copper is too small for an OCPD of 100 amperes according to NEC Table 250.122.
- C. 2 AWG copper is significantly larger than required for a 100-ampere OCPD.
- D. 4 AWG copper is larger than required for a 100-ampere OCPD, though it would be safe, it's not the minimum.
NEC EGC Sizing (Structure)
The National Electrical Code (NEC) requirement for determining the minimum size of the equipment grounding conductor (EGC) for PV array metallic support structures based on the system's overcurrent protective device rating.
- Uses NEC Table 250.122.
- Ensures a safe fault current path.
- Protects against electric shock and equipment damage.
Memory trick: Grounding size depends on the protector's power.