What is the required overcurrent protection size for feeders and branch circuits supplying electric vehicle supply equipment, based on maximum load?

The required overcurrent protection size for feeders and branch circuits supplying electric vehicle supply equipment (EVSE) is based on the maximum load that the equipment will draw. According to the National Electrical Code (NEC), the overcurrent protection must be sized adequately to handle the maximum anticipated load while also allowing for a margin of safety.

In this context, the 125% rule is applied to the maximum load of the EVSE. This means that the overcurrent protective device must be rated at least 125% of the maximum load to ensure that there is enough capacity to handle potential inrush currents or fluctuations in load that could occur during operation. By sizing the overcurrent protection at 125%, any overload conditions are adequately addressed without tripping the circuit under normal operating conditions.

Options that represent 100%, 110%, or 150% are not suitable because they either do not meet the NEC requirement for ensuring safety and reliability under maximum load conditions or exceed the necessary protection standards. Thus, the proper and recognized size for overcurrent protection according to the NEC is indeed 125%.