EV Panel Load Calculator

Check whether an existing house can take an EV charger before you quote it. Pick the 2023 NEC optional calculation for an existing dwelling (220.83) or the measured-demand method (220.87), and every step shows with its section.

For an existing house, 220.83 adds general lighting and receptacles at 3 VA per square foot, 1,500 VA for each small-appliance and laundry circuit, and the nameplate of every fixed appliance, the charger included. The first 8,000 VA counts in full and the rest at 40 percent. When heating or cooling is added or replaced on the same job, 220.83(B) takes the larger of the two out of that pool and counts it at 100 percent.

With a year of utility demand data, 220.87 starts from the highest demand on record, adds 25 percent, then adds the new charger. Divide the total by 240 V and compare it with the service rating.

The charger circuit itself is sized at 125 percent of the charger's current, because EV charging is a continuous load (625.41): a 48 A charger takes a 60 A breaker and conductors with at least 60 A of ampacity (210.19(A)(1)).

A pre-check for electricians. Verify the result against the code edition your state adopted and with the inspector before you quote. It does not replace the permit calculation.