Level 2 Charger Breaker Size Calculator
Size the breaker and wire for a Level 2 EV charger using the NEC 125% continuous-load rule. Enter your charger's output current to get the required breaker size, minimum copper wire gauge, and charging power.
The charger's max output, not the breaker. Common: 32 A, 40 A, 48 A.
Required breaker
50 A
- Min. copper wire (75°C)
- 8 AWG
- Continuous load (125%)
- 50 A
- Charging power
- 9.6 kW
NEC sizes the breaker at 125% of a continuous load (625.41, 240.6) and the wire is the minimum 75°C copper (Table 310.16).
This assumes the breaker and charger terminals are rated 75°C (NEC 110.14(C)); 60°C-rated terminations, long runs (voltage drop), aluminum, or high heat may require a larger gauge.
A real install also needs GFCI protection (NEC 210.8 / 625.54), a permit, and inspection. Your local Authority Having Jurisdiction (AHJ) may amend the NEC. Always confirm with a licensed electrician and local code.
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Open calculatorSources & standards
This tool's methodology and data follow US standards and authoritative public datasets: