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Issues with 110v gfic outlets

Discussion in 'Model 3' started by Railhawk52, Apr 9, 2018.

  1. Railhawk52

    Railhawk52 Member

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    I’ve been noticing issues when charging my model 3 with a 110v gfic outlet. I have an outlet in my garage and the model 3 trips the outlet just when it ramps up to 3 amps.

    I though it was an issue with the outlet and the wiring, but other heavy appliances work on it like my vacuum cleaner (pulls about 10amps). I tried lowering the amperage on the Model 3 to 5 amps and the same thing happens, the outlet trips.

    So I figured this was just a screwy outlet.

    At work we have 110v outlets specifically designed for electric cars (gfic as well). Every time I’ve plugged into these outlets I’ve had the same issue, they eventually trip. Sometimes right away, sometimes after 30 min.

    Last week, my car tripped the circuit again at work so I went up there to investigate. I noticed another Model 3 parked right next to me. It was plugged in but it had also tripped the circuit.

    The oddest thing is that there were leafs around us and they were charging fine and today a Model S is parked exactly where I was last week and it has been charging for over 5 hours now without tripping (I’ve checked).

    So what gives? I’ve contacted Tesla service and am having the car looked at (for other issues as well as this one) but I’m wondering if this is an issue with the gen 2 UMC, or with the software onboard the Model 3s that control the charger.

    Any thoughts on what could be causing this would be greatly appreciated.

    I have successfully charged the car from a 240 volt outlet with no issues.
     
  2. boaterva

    boaterva Supporting Member

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    So, actually it's a 120 VAC outlet... :D GFCI's measure current from hot to neutral, and if it loses any, it will complain, by tripping. It assumes some could be going through another path (you?) and cuts it off.

    The car software wouldn't have any impact on the GFCI, that's all local to the current itself being used/lost at the wall plug by the UMC.

    Also, 240 VAC charging doesn't use a neutral (it's hot to hot) and there isn't any GFCI, in any case, so that's even more evidence that the car is not at fault.

    I'm wondering if the construction of the Gen 2 UMCs has some sort of an issue, since this wasn't noted that I'm aware of with the Gen 1's.... I believe the construction was redone completely (as well as the connections/pigtail parts and the max current limited to 32 from 40 Amps). But it's weird that the current used would be 'uneven' for the 12 Amps case (I assume that's what you're using it on).

    There isn't anything for Tesla to do, besides perhaps swap the UMC. It would be interesting to test with another Gen 2 and a Gen 1!

    Here's some (perhaps too technical at the end. :) ) more information:
    Chasing “Ghost Trips” in GFCI-Protected Circuits
     
    • Like x 1
  3. eSpiritIV

    eSpiritIV Member

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    You have to be careful that you and the neighbor at your work are not charging on the same 15A or 20A circuit, as multiple receptacles could be wired together sharing the same breaker.

    Are you sure its not an AFCI circuit breaker vs a GFCI?
     
  4. boaterva

    boaterva Supporting Member

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    Good point, lots of places have Arc Fault now...
     
  5. Railhawk52

    Railhawk52 Member

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    The Model 3 at work was on a completely different outlet. I’m not positive if the outlets are all on one circuit or not, but it’s perplexig that we have a Model S that can charge with no issues but the Model 3s seem to have issues and trip the outlet.

    Is there a way to tell a gfic from afci by just looking at the outlet? I have no idea where the actual breaker is in the deck where we park.
     
  6. Craig-Tx

    Craig-Tx Member

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    Was it tripping the circuit breaker? Or tripping the GFCI circuit? Most GFCI receptacles have two buttons (TEST and RESET) If it's those then it's the GFCI circuit. If it's tripping the circuit breaker, you would have to reset it in the electrical panel.

    If it's the GFCI circuit, I wonder if the Gen 2 UMC does some test to make sure it is properly grounded by sending a small current to ground. This small current may be enough to trip a GFCI circuit.
    In any case, this needs to be brought up to Tesla Service if it is happening in multiple locations. Either there is an issue with your UMC, or there is an issue with the UMC design.

    I'll add this to my list of things to try when I get my car.
     
  7. Craig-Tx

    Craig-Tx Member

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  8. rhaekar

    rhaekar Member

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    I've been using a GFCI at home and at work with no problem while I wait to get my HPWC installed. I just plug it in and go, haven't had to adjust the current or anything.
     
  9. Railhawk52

    Railhawk52 Member

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    Thanks for the reply. It’s a GFIC circuit. I shudder every time I hear the sound of that button popping up .

    Have a service appointment for Friday and I’ll be sure and keep you all updated. I may ask if I could borrow a gen 1 charger from them to see if that fixes my issue. Then it would narrow down the problem to the gen 2 UMC.
     
  10. ElectroCat

    ElectroCat Member

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    How many people are hurt, poisoned and die, collecting resources, manufacturing and installing GFI outlets compared to the number of people they help?
    Always wanted to know if its less or more?
    Or are they false security and just a cash cow?
     
    • Like x 1
  11. Craig-Tx

    Craig-Tx Member

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    Please do. One thing to keep in mind is that GFCI circuits are fairly basic and not entirely accurate. While they are deigned to trip at a set leak current (~5 mA) remember most of these are installed by the builder and are therefore the absolute cheapest they could find using the cheapest design / parts available. Over time, they may wear out. Typically this results in them not actually tripping, but I've seen some that simply wouldn't reset.
    Also it's not uncommon for the GFCI outlet to feed other outlets (such as bathrooms, outside, etc). If some of those outlets are having minor issues, they may have small amounts of current leak that when added to the UMC small current leak are over the trip threshold.
    One example I can think of is if the outside outlets are fed from the same GFCI, it's not uncommon for years worth of weather to cause a bit of corrosion, etc. in the outside outlets. A bit of moisture in the receptacles may be enough to trip a GFCI. If you're unsure, trip your GFCI outlet (hit the TEST button) and go test other outlets to see what else went off. Focus on areas that are near water (outside, bathrooms, Kitchen, Laundry, wet bar, Jacuzzi (how fancy is your house), etc.)

    GFCI devices are not complicated devices, nor do they use any hazardous components. Yes, they occasionally do become irritating, but I'd say that if they save a single life, the cost is worth it.
     
  12. Cosmacelf

    Cosmacelf Well-Known Member

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    GFCIs go bad. My experience is that, outdoors, they last about 5-10 years.

    When a Tesla Mobile connector first starts, it checks to see if the plug has a valid ground. It does this by leaking a tiny bit of current to ground. Which is exactly what a GFCI tests for. The Mobile Connector test is supposed to be small enough or fast enough to not trip a functioning GFCI, but older and weaker ones will trip.

    Now if the GFCI trips later on in the charge session, then that’s a different fault scenario, but again, just replacing the GFCI will most often clear up the problem.

    Bottom line, I would replace the GFCI before I tried anything else (if it’s on a 20A circuit, make sure to use a 20A GFCI).

    I just read the other gen 2 GFCI tripping thread. Sounds like the gen 2 stresses the GFCI more than the gen 1 did. I would still replace the GFCI with a new one and see if that makes the gen 2 work.
     
    • Informative x 1
  13. gregd

    gregd Active Member

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    Some GFCI outlets are fussier than others. I have one in my house (built in the early 1980's) that constantly trips whenever I plug my Roadster in. When I added the 14-50 outlet in the garage, the electrician suggested that I add a set of 120v outlets next to it, as the incremental cost would be practically nothing. Those outlets, both GFCI protected, work just fine with the same car. (They're also 5-20's, vs 5-15's, so make for a good backup in case the 14-50 isn't working or is being used by another car.)

    It could be that they are just a newer design, or that the original one is just more sensitive than it needs to be (Roadsters are known to be a little leaky, but well within safe margins). The original one has always been touchy, as it also trips whenever I key up my ham radio on 15 meters CW, so it's not a matter of it going bad. It could also be a matter of other things on the same circuit, as the original also feeds the other bathrooms, kitchen, and outdoor plugs. Your garage plug may be similarly challenged.

    The only thing I can suggest is to swap out the GFCI fixture with a new one, perhaps getting one that isn't quite so fussy. I think the new ones are Leviton brand, if that helps.
     
  14. mspohr

    mspohr Well-Known Member

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  15. Railhawk52

    Railhawk52 Member

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    You were right, switching out the GFCI outlet did the trick. The electrons are now flowing! Still no clue about my work chargers. Haven’t been able to grab a charger this week to further investigate.
     
  16. Cosmacelf

    Cosmacelf Well-Known Member

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    Trust me, it's the GFCIs at work too.
     
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