TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker and becoming a Supporting Member. For more info: Support TMC

Problems charging at 110v on GFCI circuit

Discussion in 'Model 3: Battery & Charging' started by Bushcaddy, Jun 19, 2018.

  1. Bushcaddy

    Bushcaddy Member

    Joined:
    Mar 22, 2018
    Messages:
    31
    Location:
    Wasaga Beach, Ontario
    Anyone else having problems charging at 110 volts on a GFCI plug?
    I have access to the plug described above while at work, but the GFCI keeps tripping after a couple of hours.
    I’ve tried lowering the amps to as low as 8, but it didn’t help.
     
  2. eprosenx

    eprosenx Member

    Joined:
    May 30, 2018
    Messages:
    993
    Location:
    Beaverton, OR
    Hrm, this should work just fine.

    A whole ton of questions to troubleshoot this:
    • Are you positive it is the GFCI circuit tripping and not just a regular circuit breaker?
    • Is the GFCI unit the only plug on the circuit? Or are there multiple (this matters since the "fault" could be being caused by a downstream plug)
    • Are you plugging directly into the GFCI outlet with your UMC or are you plugging in with an extension cord? Or are you plugging into an outlet downstream of the GFCI that is tripping?
    • Does it always happen? Or only sometimes?
    • Is it wet or raining at all when you are using the plug?
    • Is the circuit it is on a 15a or 20a circuit? Do you know if anything else shares the circuit (upstream or downstream of the GFCI)?
    • Does the actual receptacle you are plugging into have the sideways notch that indicates it is 20a capable? Do you have the NEMA 5-20 adapter for the UMC or just the 5-15 one that came with the UMC?
    Basically I am thinking there are a number of possible issues:
    1. The GFCI is defective - this is the simplest issue - they are $20 to $25 for a replacement. Simple fix. If it is outdoors, make sure to get a "WR" rated one for outdoor use. Hopefully you are on a 20a circuit - if so, make sure to get the 20a GFCI unit.
    2. Something is wired wrong - I am wondering if ground and neutral are accidentally "bonded" (touching) somewhere downstream of the GFCI
    3. If you are using an extension cord, perhaps it is damaged and leaking current from hot to ground or neutral to ground.
    4. It could be an actual issue with the UMC or Tesla, but that seems less likely (note that the UMC is in and of itself a GFCI unit).
    I can not say I have ever run into this... Happening after several hours is weird - that sounds like a failure induced once something gets warm.

    Please report back! I am curious what the resolution will be... P.S. If it is a 20a circuit and nothing else is using it then I would recommend the NEMA 5-20 adapter for the UMC so you can get 33% faster charging than the 5-15.
     
    • Helpful x 1
  3. Rocky_H

    Rocky_H Active Member

    Joined:
    Feb 19, 2015
    Messages:
    2,460
    Location:
    Boise, ID
    I can tell a couple of things with this. Because you said "after a couple of hours", this probably does not have to do with the GFCI part of it.

    The charge cable does an initial grounding test when you first plug it in. With some old or overly sensitive GFCI outlets, that can set them off, because the ground testing method is doing the thing a GFCI is supposed to be detecting/preventing. But, that would only happen at the initial time when you plug it in and it runs that grounding test.

    If it runs for a while and then trips later, it isn't doing anything that would relate to the GFCI. It's just getting hot and tripping a breaker for standard breaker kinds of reasons. So this is probably some kind of wiring thing with the circuit.
     
  4. Bushcaddy

    Bushcaddy Member

    Joined:
    Mar 22, 2018
    Messages:
    31
    Location:
    Wasaga Beach, Ontario
    Thanks for the suggestions guys.
    These are dedicated electric vehicle plugs in a parking garage, so they should work fine.
    The last time it happened I noticed another Model 3 in the next stall had the same problem.
    It’s definitely the GFCI and Model 3 related.
     
  5. eprosenx

    eprosenx Member

    Joined:
    May 30, 2018
    Messages:
    993
    Location:
    Beaverton, OR
    Is the location protected from the rain?

    I think code may allow you to skip the GFCI outlet if you only have one single receptacle on the circuit.

    So first off, I would try multiple plugs if you have them to see if that removes the issue. Then I would call Tesla support.

    If none of that gives you a resolution I might ask the facility to swap the plug to a simplex non GFCI plug (if you are sure you don’t have a legit problem with your UMC shorting to ground). I might test with another UMC if there is another Model 3 owner that parks there with their own UMC.
     
  6. davewill

    davewill Member

    Joined:
    Feb 5, 2014
    Messages:
    853
    Location:
    San Diego, CA, US
    There shouldn't be a compatibility problem. I'd be inclined to point a finger at the GFCI first, the EVSE second. The car would be a distant third in my opinion. Replacing a GFCI outlet is usually cheap and easy, so I'd start there.
     
  7. ka9q

    ka9q Member

    Joined:
    Feb 2, 2014
    Messages:
    72
    Location:
    San Diego CA
    I agree that the problem is most likely the GFCI. But I can think of other possible causes, aside from an actual ground fault (which seems unlikely if it's dry -- tires are pretty good insulators). GFCIs are pretty sensitive devices, so one possible cause might be radio frequency noise from the car's charger (a switching power supply) conducting back through the supply cord. If I had this problem I'd try running it through a radio frequency noise filter, or perhaps a ferrite choke. (Yes, I'm an EE and a radio ham.)
     
    • Helpful x 1
  8. ponzu

    ponzu Member

    Joined:
    Apr 19, 2018
    Messages:
    285
    Location:
    Southern California
    #8 ponzu, Jun 26, 2018
    Last edited: Jun 26, 2018
    Not to hijack the thread... I am planning to charge from the 110v GFCI outlet at home, at least initially, so I am definitely interested in the topic and have marked it for watching.

    But on the quoted subject. Is this https://www.amazon.com/AC-Connectors-Household-T-Blade-Adapter/dp/B017EUTHC0/ref=pd_lpo_vtph_60_bs_t_1?_encoding=UTF8&psc=1&refRID=AZ3MX87DYFDY7MK74MA5 the kind of adapter you recommend? How would I know if my circuit is 20a? Is simply buying and plugging this adapter, and UMC into it, a safe enough test, as in, either it will work or it won't? I started learning about electricity as it applies to Tesla charging, but it was giving me headaches, so I stepped back into blissful ignorance.
     
  9. Rocky_H

    Rocky_H Active Member

    Joined:
    Feb 19, 2015
    Messages:
    2,460
    Location:
    Boise, ID
    For the first question, I would say go by looking at the outlets. Look around your house. Have you seen how some of the outlets in most of your rooms have just straight bladed slots? Those are called 5-15 and are the 15A version. But look at your kitchen outlets or maybe ones on the outside of your house. See how one of the blade slots is shaped like a T? If it's got that T shaped slot, that is a 5-20, which is the 20A outlet type. So if you are finding a building to go charge on, I would go by that.

    There is kind of a one way condition with electric code, though. If you see the 5-20 outlet, that definitely does mean it's a 20A circuit. They aren't allowed to use that outlet otherwise. But that bigger size 20A circuit is allowed to have 5-15 or 5-20 outlet types connected to it, so it's possible (although maybe rare) that a 5-15 outlet has a bigger circuit behind it.

    No, that's not a safe thing, to just plug it in and see what happens. That little adapter piece you linked to can get past the safety feature of the blade shape restrictions, so it can let you plug the Tesla UMC plug for a 20A into an outlet that is made for a 15A. That could then be drawing more current than the circuit is made for. Hopefully, the breaker would trip after a while, but if not, that can be a Bad Thing (TM). So you can only do that if you can get a chance to see the breaker for that circuit to know that it is a 20A that just happens to have a 5-15 outlet on it.
     
    • Informative x 1
  10. omgwtfbyobbq

    omgwtfbyobbq Active Member

    Joined:
    Aug 24, 2013
    Messages:
    1,235
    Location:
    Southern California
    No issues charging at 110V on a GFCI with a 50' extension cord. That same outlet did trip constantly when DW tried charging a Model X she rented for a few days.
     
  11. eprosenx

    eprosenx Member

    Joined:
    May 30, 2018
    Messages:
    993
    Location:
    Beaverton, OR
    The adapter I am talking about is the NEMA 5-20 one that Tesla sells here:
    Model S/X/3 Gen 2 NEMA Adapters

    The car comes with a NEMA 5-15 from the factory with the UMC (and a NEMA 14-50). (note the "5" in 5-15 means 120v, 6-xx means 208/240v)

    These Telsa adapters are special in that they send a signal to the UMC which sends a signal to the car telling it how much current it is allowed to draw.

    If you bought that adapter and plugged your 5-15 UMC adapter that came with the car into it, then it would be totally safe to plug into any outlet since it still would not draw more than 12 amps (it is only allowed to draw 80% of the rating of the circuit due to the face that EVSE's are considered "continuous loads - this is a safety factor). Doing this however would tell you absolutely nothing and be kind of silly. ;-)

    Now if you bought the Tesla 5-20 adapter AND that adapter from Amazon you could break one of the safety features of the NEC. Basically that 5-20 adapter tells the UMC which tells the car that it can draw 16 amps. If you plugged it into a 15 amp circuit you would (eventually) blow the breaker assuming the breaker functioned (this is the second line of defense).

    Now comes the somewhat complex thing: The NEC allows you to put either 15 amp (straight vertical blades) or 20 amp receptacles (left blade is horizontal) on a 20 amp circuit. 20 amp receptacles will accept either 15 or 20 amp plugs. 15 amp circuits can only have 20 amp receptacles.

    It is *super* common to have all 15 amp receptacles on 20 amp circuits in the US. Kitchens are required to have two 20 amp circuits but they nearly always just use 15 amp receptacles. So looking at outlets may not tell you much. What you really want to do is go look at the circuit breakers. If it is a 20 amp breaker it is a 20 amp circuit (unless someone heaven forbid used 14 gauge wiring instead of the required 12 gauge - this is super dangerous and would need fixed).

    My garage had a 20 amp circuit and 12 gauge wire, but all the receptacles were 15 amp ones. Many were cracked anyway so I replaced them all with the 20 amp receptacles just for fun in case I wanted to run something that needed the 20 amp receptacle (like my UMC at 120v 16a...). If you have a 20a circuit and want to charge your Tesla using 120v for some reason, I would recommend swapping a receptacle (or all of them on the circuit if you wish - not required) as I did. I would try to charge from the outlet that is "first in the daisy chain" closest to the panel generally so you are going through the smallest number of connector hops.

    Now to your question on that adapter:
    So I did not know those existed, I think it is cool and I ordered one! Though I am not 100% sure on the safety factor. The use case would be that you know there is a 20a circuit but it only has a 15a receptacle and you want to be able to charge at the fully 16 amps (which is what you get on a 20a circuit for continuous draw). From my understanding, what I have seen is that the 15a outlets have the exact same guts in them as the 20a ones, just they don't have the sideways notch. So the theory is that you can draw 20a no problem from the 15a outlet (though UL may disagree with this assessment - I presume they only test 15a outlets to 15a?)

    So in general, I would not recommend the use of this adapter (even though I bought one for fun). If it is your own house and it is a 20a circuit, then just replace the receptacle for a safer solution. I might consider using this adapter if I have no better option and I am darned sure it is a 20a circuit and I am there to actively monitor it at all times for heat and have a fire extinguisher handy. It could come in handy for a 33% boost in charge rate if you are stuck with just a 120v circuit.

    P.S. If the right side notch is horizontal or both are horizontal then it is a 240v circuit of 15 or 20 amp ampacity.
     
    • Helpful x 2
    • Informative x 1
    • Like x 1
  12. ponzu

    ponzu Member

    Joined:
    Apr 19, 2018
    Messages:
    285
    Location:
    Southern California
    #12 ponzu, Jun 27, 2018
    Last edited: Jun 27, 2018
    Thank you for taking the time to explain. The GFI in the garage is on a 15a circuit according to the photo of the breaker board I had taken for an electrician who was bidding on installing a new 240v circuit for a proper charging solution. The one for the kitchen GFI is 20a, but that's no help. So are the ones for the laundry room (upstairs), refrigerator, "hood" (I think I know what that means), "D.W." (dishwasher) and something labeled "G.D.". That could be "Garage Door" and if so, it's on garage ceiling and may or may not be a dual outlet. Can't wait to find out tonight. If I am to take advantage of the spare 20a outlet (may or may not be NEMA 5-20; TBD tonight), I will likely do it with the help of the appropriate gauge and rating extension cord. This is because unlike some of the forum members, I plan on carrying my UMC with me daily as I will be able to charge at work for free. I do understand which Tesla adapter I need, and I am glad that my initial misunderstanding helped you find a NEMA 5-15 to 5-20 that you found useful.

    This https://www.amazon.com/AC-WORKS-20AEX-050-Household-Anti-Cold/dp/B0733PH2Y8/ref=sr_1_11?s=hi&ie=UTF8&qid=1530136941&sr=1-11&keywords=nema+5-15+to+5-20+extension+cord&th=1 looks like it will work regardless of which outlet was installed on the 20a circuit for the G.D. if G.D. = garage door.

    There is a 50ft version for $18 more. This seems to be 12 gauge, not sure what 12/3 means. Maybe 3 wires for a total of 12 gauge?
     
  13. TaoJones

    TaoJones Beyond Driven

    Joined:
    Nov 10, 2014
    Messages:
    2,912
    Location:
    The Americas

    Just some semi-random $0.02 here during your pursuit of an optimal solution:

    “G.D.” might also stand for garbage disposal.

    May want to consider acquiring a 2nd UMC to take with for office charging. This provides some redundancy in case one or the other cables fail.

    Other than that, congrats for having not only office charging available, but gratis as well.
     
  14. ponzu

    ponzu Member

    Joined:
    Apr 19, 2018
    Messages:
    285
    Location:
    Southern California
    Dang, you must be right re: G.D. = garbage disposal.

    I considered getting a second UMC. If the ceiling outlet for the G.D.=garage door is not dual and not NEMA 5-20, then I will plug in the UMC at home into the 5-15 GFI on garage wall as originally planned. Really curious as to whether it will trip or not.

    If I get in bed with the solar panel installer who is courting me, he will install a 240v circuit to the garage for an extra $200 on top of the $18K solar job.

    And thanks!
     
    • Like x 1
  15. eprosenx

    eprosenx Member

    Joined:
    May 30, 2018
    Messages:
    993
    Location:
    Beaverton, OR
    G/D is nearly guaranteed to be garbage disposal. Can you post pictures of your panel (breakers and list of circuits and sticker with technical details on the panel on the door)?

    Garage doors are not on dedicated circuits generally. Try turning off the circuit and operate the door.

    I would highly recommend a better than 120v charging solution.

    If you are going to buy a second UMC I probably would just buy a wall connector. It is only $200 more and the install cost should be similar. You can charge 50% faster too if you have the long range model 3. 48 amps vs 32 on the UMC.
     
    • Helpful x 1
  16. dhrivnak

    dhrivnak Active Member

    Joined:
    Jan 8, 2011
    Messages:
    3,295
    Location:
    NE Tennessee
    I wired my house 18 years ago and I have had to replace 3 plugs over the years, ALL have been GFI plugs. Coincidence?? I think it more likely they are made cheaply and have to be replaced on occasion. Note this was 3 different plugs in 3 different locations. Not a single normal plug has had a problem. I also had the GFI plug on my Roadster 110V plug crap out as well.
     
  17. eprosenx

    eprosenx Member

    Joined:
    May 30, 2018
    Messages:
    993
    Location:
    Beaverton, OR
    Yeah, GFCI units have a massive failure rate.

    They are vastly more complicated than a regular outlet since they have electronics in them v.s. just metal and plastic.

    I think the specific pieces of the electronics that do the detection are also susceptible to damage by surges and bad power quality and such...
     
    • Like x 1
  18. jimmyz80

    jimmyz80 Member

    Joined:
    Dec 26, 2014
    Messages:
    418
    Location:
    Apex, NC
    For anyone still following this thread, I had a similar problem in my garage. My UMCv1 from my Model S worked just fine on my GFCI garage outlets, but the UMCv2 from my Model 3 would pop them instantly. They were no-name Chinese junk from the home builder, and I just replaced them with these Eaton GFCI outlets, which seem to have totally resolved the problem. I plugged and unplugged the UMCv2 at least a dozen times and the GFCI never popped a single time.

    https://www.amazon.com/Eaton-Self-Test-Resistant-Receptacle-Wallplate/dp/B0189B79IM/
     
    • Love x 1
  19. eprosenx

    eprosenx Member

    Joined:
    May 30, 2018
    Messages:
    993
    Location:
    Beaverton, OR
    Thanks for the feedback! Great data!

    Sounds like whatever the UMC gen 2 does for testing causes more sensitive GFCI units upstream to trip than whatever the gen 1 did? (or maybe the gen 1 did not auto test its GFCI at all?)
     
  20. Rocky_H

    Rocky_H Active Member

    Joined:
    Feb 19, 2015
    Messages:
    2,460
    Location:
    Boise, ID
    Yeah, it's such a borderline sensitive marginal issue, that it wouldn't surprise me if one version used a slightly higher current than the other, which just tilts the balance scale on some GFI outlets.
    No, they certainly did test it. I've been hearing about this off and on for years--long before the Gen 2 UMCs came along.
     
    • Informative x 1

Share This Page

  • About Us

    Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.
  • Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


    SUPPORT TMC