EV Charger Continuous Load and Panel Impact
Continuous-load circuit ampacity (125% per NEC 625.41/625.42), breaker, conductor, new panel total.
Example
You enter
- Charger nameplate (A) 48
- Panel main breaker (A) 200
- Existing service load (A) 130
- Panel busbar rating (A; 0 if unknown) 200
- Load managed false
You get
- Continuous circuit ampacity (A) 60
- Recommended breaker (A) 60
- New panel total (A) 190
- Panel headroom (A) 10
Details, formula, and sources
Continuous-load circuit ampacity (125% per NEC 625.41/625.42), breaker, conductor, new panel total, and headroom for an EVSE.
I_circuit = I_charger * 1.25 (continuous); recommended breaker = next standard size >= I_circuit; new_panel_load = existing_load + I_circuit; headroom = main - new_panel_load.
NEC 2023 (NFPA 70). Article 625 (625.41/625.42 continuous-load and load-management); 220.83/220.87 panel load; 310.16 conductor.
Free read-only access at nfpa.org/freeaccess.
Estimate. AHJ and licensed electrician govern. Verify against the NEC edition adopted in your jurisdiction.
Field names used by the API: charger_amps, main_breaker_a, existing_load_a, busbar_rating_a, load_managed, continuous_circuit_a, recommended_breaker_a, new_panel_load_a, headroom_a
- Continuous load EVSE is a continuous load; circuit and overcurrent device are sized at 125% of nameplateNEC 2023 625.41 / 625.42
- Conductor estimate the recommended conductor is a first-principles ampacity estimate (copper, 75 C, 30 C ambient); verify against NEC 310.16NEC 2023 310.16; the AHJ governs