Size the breaker at 125% of the charger’s continuous current. That means a 40 A breaker for a 32 A charger, a 50 A breaker for a 40 A charger and a 60 A breaker for a 48 A charger. The National Electrical Code treats EV charging as a continuous load, which is where the 125% rule comes from. The wire must be sized for the breaker, and a licensed electrician should confirm both.
Breaker Sizing Chart
| Charger current | Minimum breaker | Typical copper wire* |
|---|---|---|
| 16 A | 20 A | 12 AWG |
| 24 A | 30 A | 10 AWG |
| 32 A | 40 A | 8 AWG |
| 40 A | 50 A | 6 AWG |
| 48 A | 60 A | 6 AWG or larger |
*Wire size depends on cable type, run length, temperature rating and local code. Treat this as orientation, not a design.
Common Mistakes
- Setting the charger above the circuit’s 80% limit, for example 40 A on a 40 A breaker.
- Using an old dryer circuit without checking its rating; see can I plug a Level 2 charger into a dryer outlet.
- Ignoring panel capacity: the breaker can be right but the panel overloaded. A load calculation is needed.
- GFCI double protection on receptacles causing nuisance trips; see does an EV charger need GFCI.
Match the Charger to the Breaker
Many chargers can be set to a lower current to match an existing circuit. The EVDANCE EV-ACS4005T 40A NACS portable charger offers 16/24/32/40 A steps, and the EVDANCE EV-ACT5006T 48A Level 2 wall charger can be configured for its circuit at installation.
Frequently Asked Questions
What breaker do I need for a 40 A EV charger?
A 50 A breaker with wire rated for 50 A.
Can I use a 40 A breaker for a 40 A charger?
No. Set the charger to 32 A or install a 50 A circuit.
What breaker for a 48 A charger?
60 A, normally hard-wired.
Related Reading
- How Many Amps Does an EV Charger Need?
- What Size EV Charger Can I Have at Home?
- Why Does My EV Charger Keep Tripping the Breaker?
- Wallbox Home Charger Installation Guide 2026
Key Takeaways
- Breaker = 125% of charger current.
- 40 A breaker for 32 A, 50 A for 40 A, 60 A for 48 A.
- Have an electrician confirm wire size and panel capacity.