Can I use an extension cord to trickle charge?

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gringostar

Active member
Joined
Feb 17, 2015
Messages
28
Location
Santa Ana, CA
Hi,

My outlet in the garage is far from my driveway. I'd like to use a large gage extension cord to trickle charge, but the man I bought the car from says I can't use an extension cord. I've been all up and down the manual and don't see any warnings about using an extension cord. Did I miss something? Thank you!!
 
Nissan advises against it, because along with the usual reasons involving extension cords, the plug on the Nissan EVSE (charging cable) has a heat sensor to detect an overheating outlet, and the extension cord defeats it. If you take all necessary precautions, make sure that the extension cord is heavy enough (12 gauge), and make sure that outlet is in excellent condition, it is possible to use an extension cord.
 
gringostar said:
Hi,

My outlet in the garage is far from my driveway. I'd like to use a large gage extension cord to trickle charge, but the man I bought the car from says I can't use an extension cord. I've been all up and down the manual and don't see any warnings about using an extension cord. Did I miss something? Thank you!!

Nissan says no because most people will attempt to use a 14, 16, or 18 gauge cord. The electrician that installed the outlet outside my house for my car (so he knew what it was for) said that using a 12 gauge cord is fine.
 
An extension cord negates safety features built into EVSEs. They are designed to minimize any potential contact with energized conductors. That's why the inlet cords of plug-in EVSEs are so short. The EVSE protects the long cable with ground-fault interruption. The heat sensor that Leftie pointed out is another important aspect. While I might use a heavy gauge extension in an emergency, I personally would not rely upon it for everyday charging. If you do use one, make sure that no part of it is tightly coiled, as that can allow heat to build up. But you'd be better off finding a way to move the car closer to the outlet, get an outlet closer to the car, or get an EVSE with a longer cable from the box to the car.
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If you can find one and it's not much more expensive than a 12g I might also suggest a 10g extension cord. True 12 gauge's 20a rating is more than enough for the 12a an OEM Leaf EVSE would pull but still with wire you can never really go too big. Another advantage of the 10g wiring is it provides more thermal mass to dissipate any heat. Of course, if you can't find a 10g cord or it's prohibitively expensive then I'd just go with a quality 12g cord. Actually, 50' or less and a 12g is all you need, it's when you get into 100' or more you might see less voltage drop with the fatter 10g. And as has been mentioned, keep coiling or stacking of the wire on top of itself to a minimum, it can cause heat build-up which is not good.
 
I have been using a 12ga. extension cord for about 6 months new. The outdoor plug I use is on a 20amp circut. The reason why most manuactures do not reccomend usind extension cords is this,
#1 using a cord too light for the current draw, you have to figure when charging you are running at 15 amps continusly for however long you are charging which builds up a lot of heat which in turn deteroiates the cord.
#2 TRIP HAZZARD. the cord I use is attached to the skirting ( I live in a mobile home ) with clips to hold the cord off the ground and out of harms way. I also use a medium sized traffic cone ( i picked it up at Tractor Supply ) to mark where my charging lead crosses the path to my car.
make sure all connections are water tite and check the cable occaisonally for any sign of damage.
Mike
 
LeftieBiker said:
OTOH, "Unplug charger (!) when not in use." is bad advice. It causes excessive wear on the outlet and plug.

I agree. This is from 2015 owners manual. I think Nissan's view of the L1 unit then was for occasional ad-hoc charging and they expected you'd get a Level2 EVSE for everyday charging.
 
Wow, such good information and timely too. So we were thinking of taking our 2014 Leaf to our Winter Florida home where we typically drive no more than 35-40 miles a day and the EV would be absolutely perfect for us. In order to charge it would take a 50 ft extension cord that I was going to cover with conduit and bury about 10-12 inches below the surface. Thought about buying 12 ga wire just to be safe but all this talk about heat build up is concerning to me. All our charging would be overnight, perhaps as long as 10 hours @ trickle pace. So, for those of you who know, have tried this, what do you think about this plan? Any comments and advice would be appreciated.
 
I don't generally like to talk about it, but I still use a 25' 12 gauge extension cord to charge with L-1. The garage outlets are nowhere near the big doors, and the EVSE is mounted on the outside. I'm in poor health and installing the L-2 circuit has never quite happened. I've done this for 8 years and have had no issues. I'm not sure I like the idea of using an extension cord in the conduit, for the simple reason that these cords are all made in China now, and the plastic used doesn't always - or even usually - last for 10+ years. You'd be much better off with UF rated cable. And if you use 8 gauge cable the circuit can be upgraded in the future to L-2 240 volt, 30 amp charging, without having to dig the cable up and replace it. Only the wiring at the outlet and at the breaker would have to be changed around. If you use 12 gauge 2 wire (+ground), the circuit can still be upgraded to L-2 16A.
 
Amazing1 said:
Wow, such good information and timely too. So we were thinking of taking our 2014 Leaf to our Winter Florida home where we typically drive no more than 35-40 miles a day and the EV would be absolutely perfect for us. In order to charge it would take a 50 ft extension cord that I was going to cover with conduit and bury about 10-12 inches below the surface. Thought about buying 12 ga wire just to be safe but all this talk about heat build up is concerning to me. All our charging would be overnight, perhaps as long as 10 hours @ trickle pace. So, for those of you who know, have tried this, what do you think about this plan? Any comments and advice would be appreciated.
If you use 12g wire and limit your charging to 12a(OEM 120v Leaf EVSE) you shouldn't have any heat build-up, note if you used 14g which theoretically should be able to handle 12a you might have some heat built up. I kind of agree with Leftie if your burring your cable then I'd be more inclined to use UF(outdoor Romex cable) and probably use #10 gauge for future-proofing. #10 cable would be rated for 24a, well I guess if you used #8 gauge you'd be covered for the OEM 240v Leaf EVSE which can output as much as 30a, so I guess for real future proofing #8 would be best, albiet very thick and stiff cable.
 
LeftieBiker said:
I don't generally like to talk about it, but I still use a 25' 12 gauge extension cord to charge with L-1. The garage outlets are nowhere near the big doors, and the EVSE is mounted on the outside. I'm in poor health and installing the L-2 circuit has never quite happened. I've done this for 8 years and have had no issues. I'm not sure I like the idea of using an extension cord in the conduit, for the simple reason that these cords are all made in China now, and the plastic used doesn't always - or even usually - last for 10+ years. You'd be much better off with UF rated cable. And if you use 8 gauge cable the circuit can be upgraded in the future to L-2 240 volt, 30 amp charging, without having to dig the cable up and replace it. Only the wiring at the outlet and at the breaker would have to be changed around. If you use 12 gauge 2 wire (+ground), the circuit can still be upgraded to L-2 16A.

Thank you so much for that info. Just to make sure I understand you, are you saying that I would be better off purchasing good quality 12 or 10 gauge wire to be buried, then splice onto the wire the male and female plugs? And this is because the quality of the outer covering is likely to be better? Thanks
 
Just to make sure I understand you, are you saying that I would be better off purchasing good quality 12 or 10 gauge wire to be buried, then splice onto the wire the male and female plugs? And this is because the quality of the outer covering is likely to be better?

Best would be to run the cable from your breaker box, but if that isn't an option then yes. Use 12 gauge cable in that case, because you won't be able to convert it to L-2 later if it isn't wired at the breaker box. If you've never done any wiring, then try to find someone who has to attach the plug and socket ends.
 
Amazing1 said:
In order to charge it would take a 50 ft extension cord that I was going to cover with conduit and bury about 10-12 inches below the surface.
Negative. Do not run an extension cord in conduit. Do not bury an extension cord. The extension cord is the wrong material to use for that purpose.

At a minimum, you can instead take power from the receptacle, perhaps with a box extension that would allow surface mounted conduit to come out of the bottom of the extension. Then run a complete conduit system from there, underground, to a little post with a receptacle box on it (I think that is available as a purpose built all-in-one product). You could protect the circuit extension with a GFCI receptacle at the power source, then you could use PVC conduit and would only need 12" of soil cover (meaning a trench 13" deep if the conduit is 1" outer diameter). Or you could use rigid metal conduit (not EMT) and you'd only need 6" of soil cover, as long as it doesn't pass under a driveway. And of course pull in a wet rated set of conductors of the appropriate size.

If any of the above is not sufficiently familiar to you, you should hire an electrician to do it. But hopefully now you have a better sense of the scope of work and the reasonable options.

Cheers, Wayne

Edit: links are by forum ad software, not by me.
 
wwhitney said:
Amazing1 said:
In order to charge it would take a 50 ft extension cord that I was going to cover with conduit and bury about 10-12 inches below the surface.
Negative. Do not run an extension cord in conduit. Do not bury an extension cord. The extension cord is the wrong material to use for that purpose.

At a minimum, you can instead take power from the receptacle, perhaps with a box extension that would allow surface mounted conduit to come out of the bottom of the extension. Then run a complete conduit system from there, underground, to a little post with a receptacle box on it (I think that is available as a purpose built all-in-one product). You could protect the circuit extension with a GFCI receptacle at the power source, then you could use PVC conduit and would only need 12" of soil cover (meaning a trench 13" deep if the conduit is 1" outer diameter). Or you could use rigid metal conduit (not EMT) and you'd only need 6" of soil cover, as long as it doesn't pass under a driveway. And of course pull in a wet rated set of conductors of the appropriate size.

If any of the above is not sufficiently familiar to you, you should hire an electrician to do it. But hopefully now you have a better sense of the scope of work and the reasonable options.

Cheers, Wayne

Edit: links are by forum ad software, not by me.


Thank You Wayne. I do now have the right information that I need. I do not need to plan for a later conversion to a Type 2 charger since our daily use of the car will be no more than 25 miles, and I suspect every other day Type 1 charging overnight will be more than sufficient. As far as the source of our electricity, it is indeed a GFCI receptacle on our back porch and I do plan on having a permanent, close to the ground weather proof outlet about 10-15 feet from the front of where my Leaf will be parked in order to charge it overnight. The outlet will be "dead" at all times other than when I am charging. Great advice. Buy good wire intended to be buried. Say no to extension cords. Got it.
 
How do plan to connect the conduit to the existing GFCI receptacle? The conduit must be sealed the entire way and I don't know of a simple way to connect conduit to a receptacle. The best I can come up with would be to get a weather tight box extension and add that to the existing junction box that the receptacle is now mounted in. That would allow the conduit to be connected to the (now enlarged) junction box. If needed, you could still install the receptacle on the box extension or just install a cover plate to make it a simple junction box. Don't just put a plug on the end of some THHN-2 wires and plug it into the GFCI receptacle since that would be an egregious code violation.

Edit to add: if you remove the GFCI receptacle and just use the box as a junction box you should probably replace its breaker with a GFCI breaker.
 
Or the GFCI box could be connected to a junction box (make sure that the new box is connected to the "Load" terminals on the GFCI outlet) in the usual way, with plain Romex, and the conduit could then be run out of the other side of the junction box. The junction box just needs to have a conduit connector in one of the knockouts.
 
Amazing1 said:
Thank you so much for that info. Just to make sure I understand you, are you saying that I would be better off purchasing good quality 12 or 10 gauge wire

Just make sure to read his earlier comment about why extension cords are advised against - it defeats the thermal sensor checking for an overheating outlet: https://mynissanleaf.com/viewtopic.php?f=6&t=32367#p607275

and make sure that outlet is in excellent condition
 
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