Adding an EV charger to a residential service load calculation requires special handling per NEC 625.42. Level 2 EVSE outlets are treated as continuous loads — meaning the branch circuit must be sized at 125% of the outlet rating, and the full demand is included in the service calculation. Under NEC 2026, the 125% continuous factor is waived when an EVEMS (Energy Management System) per NEC 625.48 is installed, which can meaningfully reduce the impact on service sizing. This calculator shows both the NEC 2023 and NEC 2026 calculated service size for a dwelling with an EV charger, so you can compare the EVEMS benefit for your specific installation.
Adding 40A Level 2 EVSE (9,600W) at 125% continuous = 12,000 VA added to the optional-method calculation. Without EVEMS: service demand increases by 12,000 VA — may push from 150A to 200A service. With NEC 2026 EVEMS exception: EVSE added at 100% (9,600 VA), reducing the impact and potentially keeping a 150A service adequate.
This is a variant of the full Dwelling Load Calculator — which supports both the NEC standard and optional methods with all appliances, HVAC, and EV charger loads.
Try all options in the full Dwelling Load Calculator →