Section 625.40/Electric Vehicle Charging Equipment
NEC 625.40 covers branch circuit sizing for EVSE including continuous load calculations and automatic load management systems.
Branch circuits supplying electric vehicle supply equipment (EVSE) must be sized based on the maximum load of the EVSE. For continuous loads (charging sessions exceeding 3 hours, which is the typical case), the branch circuit must be rated at 125% of the maximum load. A 40-amp Level 2 charger requires a 50-amp circuit (40 x 1.25). The 2023 NEC added Section 625.42 requiring that branch circuits for EVSE be calculated as a continuous load unless the EVSE is listed for a different duty cycle. Section 625.44 permits an automatic load management system (ALMS) to reduce the total calculated load when multiple EVSE share a feeder.
Why this section exists
Electric vehicle adoption is accelerating and EV charging represents a significant electrical load. A single Level 2 residential charger draws 32-48 amps continuously for hours, often doubling the home's peak electrical demand. In commercial buildings and parking garages, dozens or hundreds of EVSE can create enormous feeder and service demands. The NEC provisions ensure circuits are properly sized for the continuous nature of the load and provide the ALMS option to make large-scale EV charging economically feasible without massive electrical infrastructure upgrades.
What plan reviewers look for
Plan reviewers check the panel schedule for EVSE circuit sizes and verify the 125% continuous load calculation. They check the feeder and service load calculations to confirm EV charging loads are included. For multi-unit installations, they verify whether an ALMS is used and that it is listed for the application. They check for dedicated circuits (EVSE typically requires a dedicated branch circuit) and verify overcurrent protection sizing.