CSLB C-46 Solar ContractorElectrical and Plumbing CodesMedium
A solar contractor is installing a new residential PV system. The system's inverter has an output circuit rated for 30 amperes. According to the National Electrical Code (NEC), what is the minimum required size for the equipment grounding conductor (EGC) for this circuit if it's run in a conduit with a 75°C rated conductor?
- A12 AWG copper
- B10 AWG copper
- C14 AWG copper
- D8 AWG copper
Show answer & explanationAnswer & explanation
Correct answer: B. 10 AWG copper
According to NEC Table 250.122, for a circuit with an overcurrent device rating of 30 amperes, the minimum required size for the equipment grounding conductor (EGC) is 10 AWG copper. This table dictates EGC sizing based on the rating of the overcurrent protective device.
Why the other options are wrong
- A. 12 AWG copper is for circuits up to 20A.
- C. 14 AWG copper is for circuits up to 15A.
- D. 8 AWG copper is for circuits up to 60A, which is larger than required for a 30A circuit.
NEC EGC Sizing
The process of determining the minimum required size for an equipment grounding conductor (EGC) based on the rating of the overcurrent protective device, as specified in NEC Table 250.122.
- Based on overcurrent device rating.
- Ensures proper fault current path.
- Table 250.122 is the primary reference.
Memory trick: Grounding conductor size depends on the fuse; check the table, you can't lose!