EVSE (Car charger) using an extension cord

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marmathsen

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Seattle, Washington ...ish
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Electrical Contractor
I have a client who wants us to install a 240V 50A EVSE receptacle at their residence. If we mount it to the house, it's not long enough to reach her car so she was planning to use an extension cord like a bunch of her neighbor's are doing. I told her this was a bad idea because there is a lot of current for several ours at a time and in an outdoor corrosive environment, and that's not an appropriate application for an extension cord.

My question is, Is there an actual code or something I can point to that would back up my claim? Is there any sort of cord or installation that safely allow the use of an extension cord?

I had recommended she purchase an EVSE with long cord. Looks like Art 635 of 2020 NEC allows up to 25' total length.

If these options aren't going to work then we may need to go underground to get closer but I'm trying to exhaust other options before that.
 
J1772 extensions are available for the load side of the EVSE. I’m not sure this is any better than a line-side extension, but I know a couple of people using them without issue.
 
ramsy said:
400.12 (1 & 7) for obvious uses not permitted for extension cords.
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I'm surprised that "continuous use" isn't on that list of Not Permitted. These are cord types so they could be hard wired and I guess that would make sense.

Is it actually permitted to use a regular extension cord for continuous use?

Rob G, Seattle
 
marmathsen said:
I'm surprised that "continuous use" isn't on that list of Not Permitted. These are cord types so they could be hard wired and I guess that would make sense.

Is it actually permitted to use a regular extension cord for continuous use?

Rob G, Seattle
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You can in certain instances. It was pointed out in a few posts back that tracking solar arays are permitted to do this other spot I've seen that's compliant for perminant continuous use is pendant drops using SO type cords.
 
marmathsen said:
Is it actually permitted to use a regular extension cord for continuous use?
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Not for unlisted assemblies from Amazon.com, or elsewhere, per 400.6(B)

If listed, Article 400 doesn't exclude continuous loads, so 125% adjustment should apply per 625.41 & 42.

Unless UL 817 listing standard already includes continuous-load testing for ampacity markings?
 
625.17(C) Overall Cord and Cable Length. The overall usable length shall not exceed 7.5m (25 ft) unless equipped with a cable management system that is part of the listed electric vehicle supply equipment. Finding a listed assembly may be an endeavor of its own but if found is allowed per code.
 
Filthy said:
625.17(C) Overall Cord and Cable Length. The overall usable length shall not exceed 7.5m (25 ft) unless equipped with a cable management system that is part of the listed electric vehicle supply equipment. Finding a listed assembly may be an endeavor of its own but if found is allowed per code.
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Especially one for outdoor use.
 
retirede said:
J1772 extensions are available for the load side of the EVSE. I’m not sure this is any better than a line-side extension, but I know a couple of people using them without issue.
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Would you agree that these likely are not allowed?

My interpretation of 625.17(C) is that, with the exception of a listed cable management system, there is no situation where you can exceed a total length of 25ft. Furthermore, even you were only using a J1772 extension in order to get to the maximum 25ft, wouldn't it need to be listed as part of the EVSE system, which I think 625.17(D) is referring to.
 
marmathsen said:
Would you agree that these likely are not allowed?

My interpretation of 625.17(C) is that, with the exception of a listed cable management system, there is no situation where you can exceed a total length of 25ft. Furthermore, even you were only using a J1772 extension in order to get to the maximum 25ft, wouldn't it need to be listed as part of the EVSE system, which I think 625.17(D) is referring to.
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625.17 (B) clearly states that the cable must be either 1. A type listed in table 400.4
OR
2. Integral with the supply equipment.

It would seem that 1. allows cables that are not part of the equipment.

To me, the sections you cite aren’t clear if they are referring to only the cable that is part of the equipment, or the total length including extensions. The latter would make the most sense, but it doesn’t explicitly state that.

Section (D) refers to cables between equipment modules, not the one going to the EV.
 
retirede said:
625.17 (B) clearly states that the cable must be either 1. A type listed in table 400.4
OR
2. Integral with the supply equipment.

It would seem that 1. allows cables that are not part of the equipment.

To me, the sections you cite aren’t clear if they are referring to only the cable that is part of the equipment, or the total length including extensions. The latter would make the most sense, but it doesn’t explicitly state that.
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Valid point. I guess so long as the extension cable is itself listed per 625.6 then maybe extensions are approved.

retirede said:
Section (D) refers to cables between equipment modules, not the one going to the EV.
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I might quibble on this point though. 625.17(D) reads:
Interconnecting Cabling Systems.
Other cabling systems that are integral parts of listed EVSE and are intended to interconnect pieces of equipment within an EVSE system using approved installation methods shall be permitted.

And EVSE is defined as:
Electric Vehicle Supply Equipment (EVSE).
Equipment for plug-in charging, including the ungrounded, grounded, and equipment grounding conductors, and the electric vehicle connectors, attachment plugs, personnel protection system, and all other fittings, devices, power outlets, or apparatus installed specifically for the purpose of transferring energy between the premises wiring and the electric vehicle.

Which the EV connector is the part that connects to the vehicle. So I THINK that would bring us back to the thought that the J1772 extension needs to be "integral part of listed EVSE".

So then maybe something like the link below (20' EVSE + 40' extension) may be allowed since the EVSE is listed, if you can make the argument that the extension is "integral". Although of course it'd be well over the 25', so there's that...

https://ev-lectron.com/products/j17...e-ev-charger-40ft-j1772-extension-cord-bundle

Sometimes these code rabbit holes make my head hurt...😵‍💫

Rob
 
marmathsen said:
Valid point. I guess so long as the extension cable is itself listed per 625.6 then maybe extensions are approved.


I might quibble on this point though. 625.17(D) reads:
Interconnecting Cabling Systems.
Other cabling systems that are integral parts of listed EVSE and are intended to interconnect pieces of equipment within an EVSE system using approved installation methods shall be permitted.

And EVSE is defined as:
Electric Vehicle Supply Equipment (EVSE).
Equipment for plug-in charging, including the ungrounded, grounded, and equipment grounding conductors, and the electric vehicle connectors, attachment plugs, personnel protection system, and all other fittings, devices, power outlets, or apparatus installed specifically for the purpose of transferring energy between the premises wiring and the electric vehicle.

Which the EV connector is the part that connects to the vehicle. So I THINK that would bring us back to the thought that the J1772 extension needs to be "integral part of listed EVSE".

So then maybe something like the link below (20' EVSE + 40' extension) may be allowed since the EVSE is listed, if you can make the argument that the extension is "integral". Although of course it'd be well over the 25', so there's that...

https://ev-lectron.com/products/j17...e-ev-charger-40ft-j1772-extension-cord-bundle

Sometimes these code rabbit holes make my head hurt...‍

Rob
Click to expand...

But there is no definition for “EVSE system”.
And just because 625.17(D) describes something that’s “permitted”, it doesn’t mean that everything else is not permitted.

+1 on the headache!
 
ramsy said:
Not yet, but being considered.
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Note that I am not advocating the use of an extension cord, I think it's use in a parking lot on an ongoing basis provides all kinds of opportunities for bad things to happen. But I don't think it's an electrical code issue either. Maybe a fire code thing.
 
I have posted this before, but it is a check list of things to remember when installing an Electrical Vehicle charger.
 

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  • Article 85 - Electric Vehicle Charging Station and Checklist.pdf
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