A Level 2 charger runs on 240 volts and adds roughly 20 to 40 miles of range per hour for most cars. Size it with the 80 percent rule: a 40 A circuit supports a 32 A charger (7.7 kW), a 50 A circuit 40 A (9.6 kW) and a 60 A circuit 48 A (11.5 kW, hardwired). Match the connector to your car (J1772 or NACS), and have an electrician check panel capacity.
Level 1 charging from a standard 120-volt outlet adds only a few miles per hour. Most owners install Level 2 at home. The choice comes down to circuit size, connector and installation.
Circuit size and charging speed
EV charging is a continuous load, so the circuit is sized at 125 percent of the charger current, the 80 percent rule.
| Circuit | Max charger current | Power at 240 V |
|---|---|---|
| 30 A | 24 A | 5.8 kW |
| 40 A | 32 A | 7.7 kW |
| 50 A | 40 A | 9.6 kW |
| 60 A | 48 A | 11.5 kW |
Your car’s onboard charger also caps the rate. Buying a 48 A charger for a car that accepts 32 A gives no speed benefit today, though it may help with a future car.
Plug-in or hardwired
Plug-in chargers use a NEMA 14-50 or 6-50 outlet; use a quality industrial-grade outlet and a 50 A circuit, and expect a 40 A maximum. Hardwired installs allow 48 A and are often required outdoors.
Connector
| Connector | Used by |
|---|---|
| J1772 | Most non-Tesla EVs sold in North America through the mid-2020s |
| NACS (SAE J3400) | Tesla, and a growing number of other automakers’ newer models |
Pick the connector your car uses and keep an adapter for the other.
Panel capacity
A new 40 to 60 A circuit may exceed your panel’s spare capacity. An electrician can do a load calculation. Load-management features or a smart panel can share capacity with other large loads. See our backup power comparison if you are planning a battery too.
Smart features and listings
Look for UL or ETL safety listing, ENERGY STAR certification, scheduling for off-peak rates and support for your utility’s rebate program. Browse power and energy.
Common questions
What size breaker do I need for an EV charger?
The breaker must be rated for 125 percent of the charger's continuous current. A 32 A charger needs a 40 A circuit; a 48 A charger needs 60 A.
Plug-in or hardwired charger?
Plug-in chargers on a NEMA 14-50 outlet are limited to 40 A on a 50 A circuit. Hardwired units can go higher and avoid outlet wear.
What is the difference between J1772 and NACS?
They are different connector shapes. NACS (SAE J3400) is the Tesla-style plug many automakers are adopting; adapters exist between the two.
Do I need a permit to install an EV charger?
Usually, yes. Most jurisdictions require an electrical permit for a new 240-volt circuit.