Persistent GFCI trip by Plug-In 2014

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by Aleid, Apr 12, 2026 at 8:39 PM.

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  1. Aleid

    Aleid New Member

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    I bought my car used in 2021. My garage wiring wasn't up to code so I didn't charge it until I could afford new wiring. After that, I noticed the GFCI would trip occasionally while charging. The frequency increased so I called the electrician, who replaced the outlet. He said the frequency increased because each fault on the circuit damages the GFCI slightly; it will trip increasingly easily as that damage increases over time. After several months, the same problem happened again. The second time the electrician replaced the outlet, he put in a dedicated 20 amp circuit for charging. He said if the problem happened again with the dedicated circuit, the problem was with the car or cable.

    Guess what's happening again? The GFCI has tripped during 3 of the last 4 times I've charged the car. I might get half a charge, 75% of a charge, etc. The charging cord from the dealership appears new. I tried having the dealer troubleshoot, but all I got was a funny look; they charged the car for me, but it won't trip their breaker because I don't charge there all the time.

    Does anyone have any suggestions for me to try, or to tell the dealer to try? I don't want to replace the charging outlet every year or two...
     
    #1 Aleid, Apr 12, 2026 at 8:39 PM
  2. PriusCamper

    PriusCamper Senior Member

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    GFCI have a short lifespan, especially the cheap ones... Flip the breaker off and install one you buy at the store yourself and install yourself. Person who worked on it last probably did a substandard job with substandard parts. Very easy fix if you do it yourself!
     
    #2 PriusCamper, Apr 13, 2026 at 3:08 AM
  3. bisco

    bisco cookie crumbler

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    consider a non gfci outlet, they can be finicky with car charging, or try to find another place to charge regularly, or another evse to try.
    a hardwird evse is another solution
     
    #3 bisco, Apr 13, 2026 at 2:49 PM
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  4. BiomedO1

    BiomedO1 Senior Member

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    You don't need a GFCI outlet on that dedicated circuit; unless it's mandated electrical code. If it is a local code requirement, that electrician can't help you - because he's legally obligated to install it that way. Do what bisco said; toss that GFCI and install a single 20A outlet. That giant black block on your charging cord is your safety cut-off and has a GFCI circuit built into it.
    The other thing; is that heavy block dangling; all weight on the plug prongs? When the electrical connectors heat-up, they could move/slip, causing the GFCI to activate. That's why everything works when the electrician leaves and it acts up a few weeks later. Those internal electrical connectors loosened up due to heat and usage.
    There are specifications tied to commercial grade electrical hardware (ie. hospital grade outlet). Household outlets, not so much. You can let your imaginations run wild on that one.......

    Good Luck and hope this helps.......
     
    #4 BiomedO1, Apr 13, 2026 at 3:14 PM
  5. Aleid

    Aleid New Member

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    Thanks, all; pretty sure the GFCI is required by code here where I live. The giant black box is suspended to avoid putting strain on the plug. Electrician had installed wiring for EV charging elsewhere but hadn't seen this issue before. Anyway, thanks.
     
    #5 Aleid, Apr 13, 2026 at 8:36 PM
  6. BiomedO1

    BiomedO1 Senior Member

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    What is currently installed? A general household 15A GFCI outlet or a commercial 20A GFCI outlet? Do you know how to tell the difference?? You stated earlier that a dedicated 20A circuit was installed; there should be a 20A outlet socket there.
    Try replacing the GFCI outlet with a "certified hospital grade 20A GFCI socket"; rather than a cheap household one. See if that makes a differences. Also see how hot that plug and socket is getting in the middle of a charging cycle.
    Please elaborate on "suspended" black box????? Is it on a peg, so it doesn't dangle? All weight off the plug - No tension on the plug?

    Fun-fact; GFCI outlets are engineered to fail-open. If something happens it cuts the power; ditto with circuit breakers - to avoid burning down the house. This may be a simple case of cheap equipment used on the install. I believe a standard 15A household GFCI is $7; whereas certified commercial hospital grade 20A is $25. A big difference in quality and materials.
     
    #6 BiomedO1, Apr 14, 2026 at 10:03 AM
    Last edited: Apr 14, 2026 at 3:34 PM
  7. Aleid

    Aleid New Member

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    Thanks for the tips; I'll look into that. I used one of the top electricians in my area - they do mostly business work. The fellow told me he was replacing the regular wall outlet with dedicated 20 amp outlet because of the repeat problem with GFI failing in less than a year. This one lasted longer than the other two, but it's still only a couple years old. Nowhere else have I ever seen GFIs trip in my house; they trip in my lab at work, and there I blame shoddy materials (they've tripped randomly, nothing plugged in, since the building was new).

    For the black brick in the middle of the cord, the manual stated that it had to be supported so the plug wasn't holding up the brick. I don't have a shelf available at the right level to hold the brick, so I used the hole provided in the brick, put a little carabiner in it, and used a strong cord to suspend the carabiner from a shelf above. The wire exits the plug straight, takes a slight curve to the side before entering the black brick, but no apparent tension or drag on the plug itself. Was that what you were wondering about?

    I'll check the temp during charging. Thanks again.
     
    #7 Aleid, Apr 14, 2026 at 9:42 PM
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