Extension cord recommendation for stock 120v charger

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Luke001

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Hello all,

I was wondering if anyone uses an extension cord along with their stock charger. I have a regular 120v? Outlet in the outside of my house, but it's a bit farther than the stock cable, so was wondering if you recommend using an extension cord and what kind? I'm confused about those 14/3 12/3, 10/3 I'm assuming the lower one is better (more expensive?)
Thanks for your help
 
14/3 is max at 15 amps. 12/3 is max at 20 amps and 10-3 is max at 30 amps. Check the amps listed on the charger and select the extension cord that covers that amperage. Also the amps for the charger should not be more than 80% of the max of the extension cord rating. 80% of 15 amps is 12 amps for a 14/3. You probably will only need a 14-3
 
I would add that however the manual does not recommend using extension cables, I had to do it sometimes, and discovered that even with proper rated cable cheap Chinese-made connectors got very hot very fast. So I cut them off, got a better ones with screws, put them on the cable and heat issue gone.
 
Resistance has to do with length. So for a given load, a 14ga extension cord might be ok for lets pretend 20 feet, but you would need a 12 ga to go 50 feet. If you only needed to get an extra 6 feet, a smaller cord might be ok. As mentioned, it is frequently the interconnects that cause issues.
A 15 amp outlet[most standard duplex outlets] is wired with 14 ga wire in the wall. A 20 amp is 12 gauge. SO unless you were trying to go a very long distance, anything over 12 gauge is probably wasted.
So if you must use an extension cord, the shortest and largest gauge practical is the best answer.
 
Thank you for the explanation Fastnf! And thank you for the tip Alex800st! I remember reading somewhere about not recommending extension cord. So you modified the extension cord? Oh man, I'm too afraid to even try that. I think I'll just look for a 3rd party level charger that's long enough? Might be better.
Thank you again for your help.
 
Thank you very much for the information enirogus and Northof49! I was hoping to run the extension cord close enough to the front of the house so that I can just plug in the portable level 1 charger nearby the car, which I think is roughly 20 feet. There's a bunch of plants and stuff in the way of that outlet, so was hoping to hang the cable under the roof, that way wouldn't have to go through all the plants each time to connect. But yeah I'm also afraid that if it use the wrong extension cord it might over heat.

Thank you again for your help.
 
This is my 120v outside setup:

51396245754_a1a8ebc5b6_z.jpg


The outlet is otherwise kinda hard to reach.

As long as the extension cord is well made and of sufficient capacity, no reason not to use one.
 
Thats a long cord. Although rated for the amperage a level1 charger draws I would bet a pack of donuts it will heat up over a long period of time. There is the issue that I've read of where some charger computers are able to sense when an extension cord is used. I'm not sure how but if it were me I'd stick to 25 feet if possible and move to 10/3 which is rated for 30 amps. I'd borrow one if possible to make sure there are not any issues. I've used a 100ft 12/3 with a chop saw during house building and it gets warm after a few hours of heavy cutting.
 
My philosophy would be to not incorporate an extension cord as part of a 'permanent' setup.
There is nothing wrong with using one on a temporary basis.

If you do choose to use one on a more permanent basis, then I have the following suggestions:
  • Do not use a cord that is longer than necessary (I agree that 50' is too long, just as a general principal).
  • Step up to a gauge that is one size heavier than 'necessary' to support the expected current
  • Try to make sure that the cord is not run near anything flamable (at the ends and along the way)
  • Try to use it in a way that you are not engaging and disengaging the plugs every day (the connections are the weak link as discussed earlier)
  • Try to use it in a way where you are not constantly flexing the cord (particularly near the ends)
  • Develop a habit of feeling the temperature of the cord near the plugs during charging. This can often identify a problem before it happens.
 
I think a 12 ga cord is probably larger than the wire in the wall, so watch the interconnects for resistance and heat build up and it will most likely be fine
 
MrFixit said:
My philosophy would be to not incorporate an extension cord as part of a 'permanent' setup.
There is nothing wrong with using one on a temporary basis.

If you do choose to use one on a more permanent basis, then I have the following suggestions:
  • Do not use a cord that is longer than necessary (I agree that 50' is too long, just as a general principal).
  • Step up to a gauge that is one size heavier than 'necessary' to support the expected current
  • Try to make sure that the cord is not run near anything flamable (at the ends and along the way)
  • Try to use it in a way that you are not engaging and disengaging the plugs every day (the connections are the weak link as discussed earlier)
  • Try to use it in a way where you are not constantly flexing the cord (particularly near the ends)
  • Develop a habit of feeling the temperature of the cord near the plugs during charging. This can often identify a problem before it happens.
Click to expand...
I'll add:
  • Don't squish a cord (EVSE or extension) beneath the weight of a garage door.
 
I've been using an extension cord for months now. I started with a too long light gauge one and it definitely got warm/hot. Note that the resistance/heat generated is not just about the length and wire gauge, but also about the quality of the connections and the long one actually got almost too hot to touch at the connection to the charger. Now I'm using a heavier gauge wire and it does not get as hot as the huge wire of my 40 amp 220 volt charger which is for now dedicated to my VW.
 
I charge almost nightly with 120 V and an extension cord. The cord is about 15 feet and a 10 guage. I wanted to be extra careful. The charger uses close to 15 amps.
 
The above posts have some very good advice. The proper answer is that technically you probably shouldn't use an extension cord for the wall end. Obviously, this works fine for plenty of people (including myself).

The slightly better answer though is to get an extension for the car plug end, not the wall plug end. To do this, get a J1772 extension cable. Why is this better? It will have waterproof connectors and the extension cable will then become part of the entire charging system with monitoring by the charger/car. As usual, get the shortest length necessary. Since the extension cables aren't part of the charging spec (which maxes at either the 20 or 25ft max you see in the actual chargers), you won't find them sold by any of the reputable certified charger companies. Ie they sell certified equipment and they can't get the extension cables or adapters certified - so they don't sell them. So you're mostly stuck with various Chinese-made options - you can find these on Amazon. Lectron seems to be the most popular brand in many circles (people also seem to like their L2 chargers). If you want one made by a US company, there's the JLong brand by a company called QCCharge. It's actually also an EV repair shop in California - the owner saw some market gaps (he apparently runs in online EV circles), so he made a product line. He's got extension cords, chargers, and adapters. They're not cheap by any means, but after receiving mine - they certainly are beefy. I picked up the 40amp 20ft extension cable and a Tesla->J1772 adapter (for when I run into hotels that only have Tesla L2 chargers - which has happened). Stock goes in and out - if you call or email they'll give you an estimate, which was right in my case (a human there also sent me an email to let me know it was in back in stock!).
 
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