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Model 3 and GFCI woes :(

I was searching the interwebs and came across this site and some of the posts involve GFCI 110v outlets and the Tesla vehicle chargers. We picked up a Model 3 the other day and it wont charge at home. Home was just built, literally, and it seems all of the breakers in the panel are GFCI so the receptecles themselves dont have it built in, its at the break box itself. Building code specifically states I cannt replace the GFCI breaker with a standard one as the garage is consider outdoor use. Any suggestions here?

We previously owned a Model S and never had these type of issues and we took that vehicle everywhere and it never once failed to charge regardless. I wonder if Tesla changed something with teh Model 3 charger?
 
I should note, the GFCI breaker does not trip. It still works fine. Nothing is on that same circuit that I am aware of, unless the house is wired strangely. All of my testing I did showed the circuit is not shared at all. The Tesla Model 3 charger blinks 3 red lights, which accoring to their documentation states "Relay/contactor fault."
 

Rocky_H

Well-Known Member
Feb 19, 2015
7,851
9,882
Boise, ID
That is always going to be a bit finicky. Search here for other threads on "GFI" or "GFCI". The ground test that the mobile charge cable does is the very thing that GFCI's are supposed to be detecting for, so they really don't like that if they detect it. But they are supposed to have threshold for it to allow a very little bit, and the amount of current the Tesla UMC uses is very tiny and usually underneath that tripping threshold, but old GFCI's frequently drift out of spec and keep nuisance tripping on that. I don't really know what to advise in your case, though, since you said it's all very new.
 

Rocky_H

Well-Known Member
Feb 19, 2015
7,851
9,882
Boise, ID
I should note, the GFCI breaker does not trip. It still works fine. Nothing is on that same circuit that I am aware of, unless the house is wired strangely. All of my testing I did showed the circuit is not shared at all. The Tesla Model 3 charger blinks 3 red lights, which accoring to their documentation states "Relay/contactor fault."
Oh. Well that is probably a different thing then. I've seen that they've had a fairly high amount of bad UMC units, so you might just have a bad one that needs to be replaced. Try using that to charge at a few other places, and see if you have that same fault light on different locations and circuits.
 
That is always going to be a bit finicky. Search here for other threads on "GFI" or "GFCI". The ground test that the mobile charge cable does is the very thing that GFCI's are supposed to be detecting for, so they really don't like that if they detect it. But they are supposed to have threshold for it to allow a very little bit, and the amount of current the Tesla UMC uses is very tiny and usually underneath that tripping threshold, but old GFCI's frequently drift out of spec and keep nuisance tripping on that. I don't really know what to advise in your case, though, since you said it's all very new.

I requested the home builder send someone out to take a look and make sure everything is properly conencted. The home was buil 90 days ago but its always possible the GFCI breaker is bad I guess.
 
Oh. Well that is probably a different thing then. I've seen that they've had a fairly high amount of bad UMC units, so you might just have a bad one that needs to be replaced. Try using that to charge at a few other places, and see if you have that same fault light on different locations and circuits.

Works everywhere else. Just not at the house. We thought it was the UMC but after testing concluded it was fine. I asked Tesla to swap it out anyway and the problem persists.
 
Oh. Well that is probably a different thing then. I've seen that they've had a fairly high amount of bad UMC units, so you might just have a bad one that needs to be replaced. Try using that to charge at a few other places, and see if you have that same fault light on different locations and circuits.
Yeah, it sounds more like a grounding problem or a miswired outlet. Exactly what does the UMC do? If there's flashing lights, the flashing pattern will indicate what the problem is.

BTW, if they used the type of connection that stabs into the back of the outlet and uses a spring to hold the wire, I'd suggest moving the wires under the screws instead. If it stabs in, but the connection is then tightened by a screw, then it should be OK so long as the wire was stripped properly.

Electrical Outlets: Side Wire versus Back Wire
 
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Yeah, it sounds more like a grounding problem or a miswired outlet. Exactly what does the UMC do? If there's flashing lights, the flashing pattern will indicate what the problem is.

BTW, if they used the type of connection that stabs into the back of the outlet and uses a spring to hold the wire, I'd suggest moving the wires under the screws instead. If it stabs in, but the connection is then tightened by a screw, then it should be OK so long as the wire was stripped properly.

Electrical Outlets: Side Wire versus Back Wire


The UMC flashes with 3 red lights. The error is not very helpful.
 

jmaddr

Active Member
Mar 29, 2019
1,150
1,142
Florida
- Have you tried another outlet at your house? On a different circuit?
- Check the manufacturer of the GFCI breaker in the panel. Goto HD/Lowes and get another manufacturer (Siemens/GE/etc) and see if there is any difference.

However, in the end I think you are chasing something that is really a waste of resources. 120V charging really isn't tenable. Why not call an electrician and have them wire a 240V outlet?
 
Tested on the neighbors home and had the same results.

Tried an outlet on another circuit and had the same results.
That suggests it is a bad interaction between your car and the particular breakers that were used. There's a slight chance it could still be a bad batch of breakers if they did both homes at the same time, but it's very unlikely. The main issue is whether the problem is specific to your car or the breakers. The way to figure out if it's only your car is to invite another Tesla to come charge at your home. Meanwhile, get a different model/maker of AFCI/GFCI breaker and install it in place of one of your existing ones. If that fixes the problem, the answer is to just replace all the breakers. Hopefully the builder will foot the bill for that.

I am going to get a 240v installed but I want to make sure there isn't something wrong with my homes wiring before I do such.

Having the same problem at the neighbor's pretty much rules out a wiring problem in your home unless it's something they did on BOTH houses. It's not clear you would have the same problem on a 240v circuit, anyway. Is there any way you can plug into a dryer or range plug on a test basis before having the electrical work done?

I hesitate to suggest this, but another thought would be to install a very temporary plug by wiring a 50a breaker to a 14-50 outlet that you would install and let hang out the front of the panel long enough to test with. The parts could be reused when you do the real install. NOTE: I am NOT recommending you do this. It's something I might try if I couldn't think of a better way to diagnose the problem. If it seems like a good idea to you and you feel confident you could do it safely...
 
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If the GFI breaker doesn't trip then the problem has nothing to do with the GFI breakers.

If you still think the problem is the breaker (why?), go to Home Depot or Lowes and get a $10 GFI outlet tester. Plug it in, push the button, and the breaker should trip. The tester's light pattern will tell you if the outlet is wired correctly. example tester

The UMC manual says that for the relay/contactor fault: Unplug the Mobile Connector from the vehicle and then plug it back in. Try a different outlet. If the error persists, contact Tesla..

Sounds like a bad UMC or fault with the car's charging system.
 

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