What gauge extension cord should I use for EV charging?

Use at least a 12-gauge outdoor extension cord, but 10-gauge is safer for longer runs. Standard indoor cords aren’t built for continuous high current and risk overheating or fire. For Level 1 charging, 12-gauge is the minimum; go to 10-gauge if the cord is 50 feet or longer. Always choose an outdoor-rated cord with a weather-resistant jacket and a tight, molded plug.