Case: the EV charger on a 100-amp service
In one paragraph
A handyman-turned-contractor hangs a 48-amp hardwired charger on a 60-amp breaker in a full 100-amp panel, no permit, no load calculation, and the main breaker trips at dinner the first night the car charges. The homeowner calls Priya Natarajan, who runs the Article 220 numbers on the kitchen table and works three honest rungs: a 200-amp service upgrade, a charger turned down behind a listed load-management system, and the utility's twelve months of demand data under 220.87 to see whether the house is really as full as the paper says. On this house the code's 7,200 volt-ampere floor for any EVSE means only the upgrade closes, the homeowner picks it, and the charger stays de-energized and tagged until the service can carry it. The names are invented; the arithmetic is the code's.
The rule
An EVSE is added to a dwelling load calculation at 7,200 volt-amperes or its nameplate, whichever is larger (2025 CEC 220.57), and the service must carry the resulting demand under 220.82 or, for an existing dwelling, under 220.83 or the utility-data method of 220.87; the branch circuit is protected at 125 percent of the EVSE's maximum load (625.41) and may be sized to the setting of a listed energy management system (625.42). Installing an EV circuit is an alteration of the electrical system that requires a permit (89.108.4.1), which state law requires the jurisdiction to issue administratively (Gov. Code 65850.7(b)).
Why it matters
The EV call is where a contractor either does thirty minutes of arithmetic or hangs a box that trips the whole house, and the difference is visible to the customer the first evening. The case is about the calculation, the load-management rung most new contractors do not know exists, and the permit the first installer skipped.