Use a 10-gauge or 12-gauge outdoor extension cord for EV charging.

Yes, you need a heavy-duty outdoor cord — at least 12-gauge, but 10-gauge is safer for longer runs.

Standard indoor extension cords (16-gauge or even 14-gauge) aren’t built for the continuous high current an EV pulls. Over a few hours, that thin wire heats up, voltage drops, and you risk tripping breakers or starting a fire. Go thicker. 12-gauge is the minimum for Level 1 charging (120V, 12A continuous). If your cord is 50 feet or longer, step up to 10-gauge to minimize voltage drop.

Outdoor rating is non-negotiable. You need a cord with a weather-resistant jacket (marked “W” or “outdoor”) and a three-prong grounded plug. Even if you charge in a garage, moisture and dust get everywhere. Don’t trust a “garage” cord that’s really indoor.

Also check the plug ends. Some cheap outdoor cords use loose-fitting connectors that can overheat over time. Look for a tight, molded plug — ideally with a rating for “EV use” or “heavy duty.” Tesla and other manufacturers often recommend against extension cords entirely, but if you have to use one, this is the way.

Don’t skimp — this is a fire and safety risk, not a place to save twenty bucks.