Don't use an extension cord with an EV charger. If you have to, use the heaviest, shortest one you can find.

I wouldn’t. Most EV manufacturers explicitly warn against extension cords, and for good reason. An EV charger pulls high amperage for hours—not minutes like a power tool. A standard 14-gauge cord will heat up, melt, or start a fire. Even a “heavy duty” 12-gauge cord is sketchy for a Level 2 charger pulling 32 amps.

If you absolutely must (temporary emergency, Level 1 charger only), here are the minimums:

• Use a 10-gauge cord (12-gauge for Level 1 at 12A max).
• Keep it as short as possible—25 feet max.
• Make sure it’s rated for outdoor use and 100% copper (avoid copper-clad aluminum).
• Plug it directly into a GFCI outlet, no daisy-chaining.

Even then, check the cord temperature after 30 minutes. If it’s warm, you’re playing with fire.

Better option: install a proper charger or have an electrician move the outlet. Extension cords are a workaround, not a solution.