Becoming an EV driver, you may quickly realize that Level 1 (120v) charging may not deliver enough energy to cover your daily driving needs, and Level 3 public charging may be inconvenient to use on a daily basis. So now that you’re thinking about installing a Level 2 (240v) charging station in your garage, you will need to consider the household circuit breaker requirements.
How many amps are required for Level 2 charging at home? Most Level 2 charging stations have configurable amperage modes. So a 40 amp home charger may be able to be restricted to 32, 24, 20, 16, and in some cases as low as 10 amps.
Electrical codes in the US and Canada require that your constant load does not exceed 80% of the circuit breaker capacity. Therefore, a charger connected to a 30 amp circuit should be restricted to 24 amps.
If your home has high power 240 volt appliances like a clothes dryer or electric kitchen stove, the circuit breaker is very likely capable of supporting Level 2 EV charging. But you will need to find out the amperage rating of the circuit breaker, and work backwards to find a product that will not exceed 80% of that rating. Working with high voltage electricity is dangerous and requires special care, consultation and wiring from a licensed electrician is almost always recommended.
If your electrical box is capable of delivering enough power for Level 2 charging, the bulk of the installation work is running high gauge wiring from the circuit breaker to the parking location, this will typically cost a few hundred dollars depending on the length of the run. However, if your electrical box requires upgrades to support a higher load, this may inflate the cost into thousands.
Most contemporary homes will support at least 40-50 amp circuits without requiring additional upgrades, allowing the driver to charge at 32 or 40 amps. This is more than enough power to recharger a passenger car overnight. However, some heavy duty Level 2 chargers such as the Ford Charge Station Pro (for the F-150 Lightning) are capable of pulling up to 80 amps. Most homes will require electrical upgrades to support a 100 amp circuit.