Charging an EV? Don't Use an Extension Cord

Many electric vehicle manufacturers provide a Level 1 charging cord when you buy an EV or a plug-in hybrid (PHEV). These "trickle chargers" don't require special equipment to use and connect to a standard 120-volt electrical outlet at home or elsewhere. The cable length can range from 6 feet to 20 feet or more depending on vehicle make and model.

If that charging cable isn't long enough to plug into a nearby outlet, you may be tempted to use an extension cord. Here's why you shouldn't.

Charging an electric car requires more electricity than the amount common home appliances need. Therefore, electric car chargers contain thicker wires that can handle more power than smaller gauge wires in typical extension cords.

"While some electric car owners have reported using a typical extension cord, we don't recommend it," says Kelley Blue Book Executive Editor Brian Moody. "In fact, Kia and other automakers specifically say not to use an extension cord in the owner's manual. An electric car pulls more power than a typical home appliance, and using a typical extension cord when charging can harm your home and car."

Owner manuals are explicit with their warnings, such as this one from Chevy to Bolt owners: "Do not use extension cords, multi-outlet power strips, splitters, grounding adaptors, surge protectors, or similar devices."

A Level 1 cable offers a slower "trickle" charge and supplies a few miles of range per hour, which is suitable for many PHEV owners. Pairing an extension cord with the charger restricts the voltage transfer. This setup will take even longer to boost your battery, in addition to creating safety concerns.

Since charging an electric vehicle draws a large amount of power, an extension cord may overheat if you connect it to the charging cable. The chance of fire increases because the extension cord attempts to transmit more energy than it was made to carry. Overheating cords can melt plugs and receptacles, and the fire danger is greater when left unattended overnight or while you’re not home.

Another safety risk is electric shock. An EV charging cable is more volatile when connected to an extension cord. Rerouting the power supply from your electrical outlet through an extension compromises the stability of this power transfer. Inserting and removing the plug then becomes a riskier task.

Consult a licensed electrician if you’ll be connecting an EV or PHEV to a Level 1 charging cable for long-term, at-home charging. An electric vehicle supply equipment (EVSE) professional can ensure you have a dedicated circuit to support the power load.

No. EV manufacturers advise against using an extension cord to charge an EV.

Charging an EV with an extension cord may result in slower charging times, electric shock, and even electrical fires.

It is possible to charge an electric car with an extension cord, but there is a significant safety risk involved. Always plug your EV charging cable directly into a dedicated wall outlet.

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