Two Level II EVSE circuits installed in the same PVC conduit. Each EVSE is served by a 40-ampere circuit at 240 volts with an EGC run along with the circuits. What size copper EGC is required for this installation?

Two Level II EVSE circuits installed in the same PVC conduit. Each EVSE is served by a 40-ampere circuit at 240 volts with an EGC run along with the circuits. What size copper EGC is required for this installation?

• A. 10 AWG
• B. 8 AWG
• C. 6 AWG
• D. 4 AWG

Answer: (A)

The key idea is how equipment grounding conductor (EGC) size is determined for circuits. For copper EGCs, NEC 250.122 sets the size based on the overcurrent protection device (OCPD) rating of the circuit. A 40-ampere circuit requires an 8 AWG copper EGC. When two circuits share an EGC in the same raceway, you size the EGC to handle the fault current for the largest OCPD in that group; since both circuits are 40 A, the EGC still needs to be 8 AWG. A 10 AWG EGC would be appropriate only for a 30 A circuit, not for a 40 A circuit. The conduit type (PVC) doesn’t change this requirement. Therefore, the correct copper EGC size is 8 AWG.

The key idea is how equipment grounding conductor (EGC) size is determined for circuits. For copper EGCs, NEC 250.122 sets the size based on the overcurrent protection device (OCPD) rating of the circuit. A 40-ampere circuit requires an 8 AWG copper EGC. When two circuits share an EGC in the same raceway, you size the EGC to handle the fault current for the largest OCPD in that group; since both circuits are 40 A, the EGC still needs to be 8 AWG. A 10 AWG EGC would be appropriate only for a 30 A circuit, not for a 40 A circuit. The conduit type (PVC) doesn’t change this requirement. Therefore, the correct copper EGC size is 8 AWG.