A Level II EVSE with a rating of 32 amperes at 208 volts is installed. What is the minimum size copper equipment grounding conductor required to serve the installation?

A Level II EVSE with a rating of 32 amperes at 208 volts is installed. What is the minimum size copper equipment grounding conductor required to serve the installation?

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

Answer: (A)

The size of the copper equipment grounding conductor is determined by the rating of the overcurrent protection device feeding the EVSE, not by the voltage. For a Level II EVSE rated at 32 A, the feeder OCPD is 32 A. Per NEC 250.122, a 30–40 A OCPD requires a 10 AWG copper equipment grounding conductor. So the minimum copper EGC is 10 AWG. If the OCPD were larger (for example, 40–60 A), the required EGC would be larger (8 AWG copper), and so on. The 208 V rating doesn’t change this sizing rule; it’s about ensuring a proper fault-current path to trip the protection device safely.

The size of the copper equipment grounding conductor is determined by the rating of the overcurrent protection device feeding the EVSE, not by the voltage. For a Level II EVSE rated at 32 A, the feeder OCPD is 32 A. Per NEC 250.122, a 30–40 A OCPD requires a 10 AWG copper equipment grounding conductor. So the minimum copper EGC is 10 AWG. If the OCPD were larger (for example, 40–60 A), the required EGC would be larger (8 AWG copper), and so on. The 208 V rating doesn’t change this sizing rule; it’s about ensuring a proper fault-current path to trip the protection device safely.