Overcurrent protection for feeders and branch circuits supplying electric vehicle supply equipment shall have a rating of not less than ___% of the maximum load of the electric vehicle supply equipment.

Overcurrent protection for feeders and branch circuits supplying electric vehicle supply equipment shall have a rating of not less than ___% of the maximum load of the electric vehicle supply equipment.

• A. 200
• B. 150
• C. 100
• D. 125

Answer: (D)

Sizing overcurrent protection for EV charging circuits hinges on the fact that the EVSE can draw a sustained current at its maximum rating and may also experience inrush when a connection is made. To cover that continuous operation and still protect the conductors, the overcurrent protection must be not less than 125% of the EVSE’s maximum load. This extra margin handles inrush and prolonged loads without nuisance trips, while keeping protection effective for faults. The other options either don’t provide enough headroom (100%) or exceed the minimum without changing the fundamental requirement (150% or 200%), so 125% is the correct standard.

Sizing overcurrent protection for EV charging circuits hinges on the fact that the EVSE can draw a sustained current at its maximum rating and may also experience inrush when a connection is made. To cover that continuous operation and still protect the conductors, the overcurrent protection must be not less than 125% of the EVSE’s maximum load. This extra margin handles inrush and prolonged loads without nuisance trips, while keeping protection effective for faults. The other options either don’t provide enough headroom (100%) or exceed the minimum without changing the fundamental requirement (150% or 200%), so 125% is the correct standard.