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Ground Fault Cable Error Message

Everything worked fine the first time I charged my 2018 Model S 100D. Tonight, when I plugged the mobile connector into the charger port--for ONLY the second time--the lighted ring started quickly flashing green, then went solid red. The dashboard error message was something like "ground fault cable".

I was on the phone with Tesla customer support for 45 minutes and went though the following:
  • Unplugging and plugging into the NEMA 14-50 receptacle. Still have the red ring when I try to plug into the charge port, and the "T" (in TESLA) on the connector flashes red twice, then pauses, then the pattern repeats again and again. Ground Fault error message on dashboard.
  • Turning the local sub panel breakers off and on. Same as above.
  • Turning the breakers on the main panel off and on. Same as above.
  • Plugging the regular 110 outlet connector into a regular outlet. Same as above.
Since the problem recurred in two different outlets on different circuits, Tech support seemed to think the problem is a my mobile connector is what has the fault.

Does anyone else have any thoughts? Should I drive to the Service Center tomorrow or call my electrician?

I've read some people discussing "dialing down" the amperage on the car's controls, but I have no idea if that would help or how to do it.

I'm in over my head. :-(
 
I think it sounds like you have a bad mobile connector. If you have a voltmeter or a test light you can check the 120v outlet. Between the small blade and ground you should get around 120V or the light should light up. Same between the small blade and big blade. Between the big blade and ground should be 0V, or no light.
Assuming this all checks out, then the problem is the mobile connector.
 
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I think it sounds like you have a bad mobile connector. If you have a voltmeter or a test light you can check the 120v outlet. Between the small blade and ground you should get around 120V or the light should light up. Same between the small blade and big blade. Between the big blade and ground should be 0V, or no light.
Assuming this all checks out, then the problem is the mobile connector.

Is this a voltmeter? I have no idea how to use it, but it seemed like a good idea at the time to have one on hand. The thing is, I only plan to use the NEMA 14-50 for charging. The only reason I plugged the mobile connector into the normal 3-prong outlet was to rule out the NEMA 14-50 outlet being faulty. Since the mobile connector didn't work with either outlet, you're probably right about the fault being with the mobile connector. Man! Good for ONE charge and then KAPUT!

Which begs the question, do you recommend having a back-up mobile connector? The ones sold online on the Tesla store only have a one-year warranty, whereas the one that came with the car have something like 5 years,
 

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That Sperry thing is not a voltmeter but it will test the grounding wich is what you want to do.
Stick it into the normal 3-prong outlet and press the black button on it, if the two yellow lights to the right of the device lights up the outlet is fine, any other combination of lights means the outlets is faulty.
 
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Everything worked fine the first time I charged my 2018 Model S 100D. Tonight, when I plugged the mobile connector into the charger port--for ONLY the second time--the lighted ring started quickly flashing green, then went solid red. The dashboard error message was something like "ground fault cable".

I was on the phone with Tesla customer support for 45 minutes and went though the following:
  • Unplugging and plugging into the NEMA 14-50 receptacle. Still have the red ring when I try to plug into the charge port, and the "T" (in TESLA) on the connector flashes red twice, then pauses, then the pattern repeats again and again. Ground Fault error message on dashboard.
  • Turning the local sub panel breakers off and on. Same as above.
  • Turning the breakers on the main panel off and on. Same as above.
  • Plugging the regular 110 outlet connector into a regular outlet. Same as above.
Since the problem recurred in two different outlets on different circuits, Tech support seemed to think the problem is a my mobile connector is what has the fault.

Does anyone else have any thoughts? Should I drive to the Service Center tomorrow or call my electrician?

I've read some people discussing "dialing down" the amperage on the car's controls, but I have no idea if that would help or how to do it.

I'm in over my head. :-(


In my local area we have a spate of people, usually the redneck denier types, rolling up those foam ear plugs and sliding them into the charger outlet ports. Check before blaming the hardware.
 
Which begs the question, do you recommend having a back-up mobile connector? The ones sold online on the Tesla store only have a one-year warranty, whereas the one that came with the car have something like 5 years,
If that Sperry tester says the outlet is OK but the UMC gives a ground fault, it seems likely your UMC has some fault (from manufacture), which has only manifested itself after the first use.

Many owners choose to have a fixed charger installed (often a Tesla HPWC) and keep the UMC in the car, for use when travelling. Wall chargers are typically weatherproof, so these are pretty much essential for anyone charging outside. Others (like myself) choose to use a UMC when charging in a garage, at home. I bought a second UMC on ebay, so I keep one in the car and the other permanently connected in the garage.

While waiting for a replacement UMC, you can still charge at superchargers and destination chargers, as these have their own charging cables.
 
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Tezzie, if your 120 V outlet works with other devices or according to the test procedure Jhelin mentioned, then it's very likely your Mobile Connector needs to be reset / replaced. The service center can help you with that. See if they can do a test for you as well with yours and if needed, the new one to make sure everything works.

The amperage setting is available from the car's charging screen (accessible using the energy symbol at the top of the screen).

Just so you're aware, Tesla can also be reached at [email protected].

Congrats on your car! Hopefully this will be the only issue you have.
 
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The UMC is more sensitive than most equipment that you'll plug into a socket at home.

I've experienced similar issues in the past - specifically at Chargepoint stations. Charging at 5A reduced the frequency of the fault error. I was able to draw 8-9A at times without an issue. To illustrate my point about the sensitivity of the UMC, other EVs charged on the same Chargepoint stations without issue.

I recommend trying to charge at another house or at a commercial location before trying to get Tesla to replace your UMC.
 
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