Residential Charging Stations for Electric Vehicles
You may be considering buying an electric vehicle (EV), or plug-in hybrid vehicle. These vehicles will help lessen our reliance on imported fuels but will require yet another power source – electricity. The EVs are powered by a large battery pack that will need a home-based charging system in order to “re-fuel”. In the Chevrolet Volt for example, the charger is installed in the vehicle, but other brands may have the chargers in garages or a weatherproof unit will stand outdoors along the driveway. Regardless the placement, most garages and some older houses will need to be rewired to accommodate the charging equipment.
The EV charger should be on a ‘dedicated’ circuit, meaning no other fixture or appliance is on that circuit. You wouldn’t want the circuit breaker to trip because someone used the garage door opener or turned on the lights. The National Electric Code® (NEC), states a number of safety requirements including over-current trip, leakage current to ground protection (GFCI), and an automatic shut-off feature for when, not if someone drives off with the cable still plugged in to the car.
Because the charger is operating for hours at a time, the following rule is in Section 625.14 of the 2011 NEC®: “Electric vehicle supply equipment shall have sufficient rating to supply the load served. For the purposes of this article, electric vehicle charging loads shall be considered to be continuous loads.” You should consult a licensed electrician to evaluate the capacity of your electric system to ensure that you are ready to install an EV charger. Heavier wiring to the garage and possibly to the house may be required. Many electricians suggest that a 50 ampere (amps) - 240 volt service run to the garage for a Level 2 charger (see below).