Extension Cords for EV Charging... is it safe?

Hey everyone, I’m close to buying a 2022 Kia Niro EV. Since I’m renting and don’t drive that much, I’m planning to stick with Level 1 charging for now.

But here’s the thing: the nearest outdoor outlet to my driveway is about 40 feet away. Would using an extension cord be a problem for that? I’ve heard it can cause some efficiency loss, but is that really an issue?

Also, the outlet is part of a covered box with 4 plugs. Two of those are used for our washer and dryer (the dryer is propane-heated, so it’s just running the tumbler). Could charging the EV at the same time risk overloading the system?

You’ll want a heavy-duty 10/3 extension cord, and make sure none of it is coiled up while in use. Check that the outlet is in good shape and that the plug fits tightly.

If it’s a 15-amp circuit, I wouldn’t run the washer or dryer while charging. If it’s 20 amps, you’re probably safe, but still, avoid running both at the same time if you can. Level 1 charging pulls 12 amps, so keep that in mind and follow the 80% rule—don’t use more than 4 amps for other devices while charging.

@diallo
A thicker cord is definitely better, but 10/3 might be overkill for a 12-amp draw. #12 wire should be more than enough, and even #14 could work for a shorter cord.

Thomas said:
@diallo
A thicker cord is definitely better, but 10/3 might be overkill for a 12-amp draw. #12 wire should be more than enough, and even #14 could work for a shorter cord.

Yeah, you’re right, but it’s a small price difference for some extra peace of mind. Plus, outdoor cords can get covered with debris or stuff, so I’d rather go a bit heavier just in case.

Using an extension cord is fine, just make sure it’s rated properly.

>I’ve heard it can cause some efficiency loss?

Don’t worry too much about that. The key is to use the right type of extension cord, not one meant for indoor lamps.

Get a beefy cord, rated for at least 1500 watts or more, and keep it as short as possible. You might also want to use a cable cover if the cord is in a spot where people could trip over it.

As for using the same outlet as the washer and dryer, think of it like running a hairdryer or a vacuum cleaner while charging. You’ll probably be fine.

@Amelia
If all four outlets are on the same 15-amp circuit, charging and using the washer/dryer at the same time could trip the breaker. If it’s a 20-amp circuit or if they’re on separate circuits, you should be good.

You should be fine, but make sure the circuit isn’t shared with anything else. Also, get an extension cord rated for 20 amps/2400 watts. A 15-amp cord can overheat if you run it for long periods, especially in hot weather.

Make sure the extension cord is rated for at least 20 amps, and keep the connection points out of the weather or dry them off if necessary.

You might run into a problem sharing the outlet with your washer and dryer while charging the car. It’s not ideal.

Christopher said:
You might run into a problem sharing the outlet with your washer and dryer while charging the car. It’s not ideal.

Could you explain a bit more? I get that all of them will pull some power. It’s a 20-amp breaker, and like I said, the dryer is propane-heated, so it’s just running the tumbler and timer.

I had issues with my 2014 Nissan Leaf when using 12-gauge cords—the car’s L1 charger just wouldn’t work with them. I ended up getting a 3-foot 10-gauge extension cord meant for air conditioners, and it’s been working great for over a year now.

As for overloading the circuit, yeah, it’s definitely possible if you’re charging and using both laundry machines at the same time.