Power Calculator Calculator for California
NEC 2023 power calculator math for EV charger installers working in California.
Converting between kW and amps is the entry point for nearly every California EV install spec — manufacturers publish kW, but the panel, breaker, and feeder live in amps.
Worked example for California
A 150 kW EVSE draws roughly 625 A at 240 V single-phase, or 180 A at 480 V three-phase. Apply the NEC 2023 125% continuous-load multiplier before sizing the OCPD or feeder. Pacific Gas & Electric (PG&E) typically meters DCFC sites at the 480 V three-phase service in California.
Code & Utilities
California currently enforces the NEC 2023 edition, adopted in 2023. That includes Article 625 (Electric Vehicle Power Transfer System) requirements: 125% continuous-load sizing on EVSE branch circuits, GFCI protection at outdoor receptacles, and provisions for energy management systems on shared circuits.
Major electric utilities serving California include Pacific Gas & Electric (PG&E), Southern California Edison, San Diego Gas & Electric, LADWP, SMUD. Each has its own service-upgrade timeline, EV rebate availability, and metering rules — confirm them before quoting commercial work.
Climate & Ampacity
Plan EV feeders against a 95°F ambient in California — the resulting NEC 310.15(B) correction of 0.88× is what trims a #6 THWN-2 down to its true continuous rating. Because the correction is below 0.9, conductors that "look fine" on a 30°C ampacity table will not carry their nameplate current here — always derate explicitly.
California takeaway
For three-phase math, always confirm the actual nameplate power factor — DCFC equipment is usually 0.95+ but older site-rated equipment can be lower, which changes the apparent power and the conductor pick.