POLL: Mobile Connector + NEMA 14-50 + GFCI Breaker Reliability

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How often does your Mobile Connector + NEMA 14-50 + GFCI setup fail to complete a charging session?

  • Never! Works 100% of the time.

    Votes: 20 76.9%
  • Rarely fails. Charge completes > 95% of the time.

    Votes: 1 3.8%
  • Occasionally fails. Charge completes 90-95% of the time.

    Votes: 0 0.0%
  • Sometimes fails. Charge completes 80-89% of the time.

    Votes: 2 7.7%
  • Often fails. Charge completes 60-79% of the time.

    Votes: 1 3.8%
  • Frequently fails. Charge completes 40-59% of the time.

    Votes: 1 3.8%
  • EPIC FAIL! Charge completes < 40% of the time.

    Votes: 1 3.8%

  • Total voters
    26

Bokonon

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#1
There are some anecdotal reports of interrupted charging sessions floating around from some Tesla Owners who charge with the Mobile Connector plugged into a NEMA 14-50 outlet on a circuit with a GFCI breaker. The typical case is a NEMA 14-50 receptacle installed near a driveway, parking space, or other outdoor/damp location, which, either per code or as a best practice, needs ground-fault protection. Since the Mobile Connector itself has a built-in GFCI, the thinking is that placing two GFCI devices in series can erroneously trigger a fault, thereby unexpectedly interrupting the charging session.

Given that there is some amount of reporting bias toward this configuration being problematic, I wanted to create a poll to help quantify the degree to which these faults occur, similar to the "phone-key failure" poll.

So, for those of you who charge your Tesla with a Second-Generation Mobile Connector plugged into a NEMA 14-50 outlet connected to a GFCI breaker: what has your experience been? Has your charging session ever been unexpectedly interrupted? If so, how often does this occur? And have you investigated the cause with your electrician (i.e. to determine whether it's being caused by a legitimate ground fault)? Or is everything just peachy?
 
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Triangles

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#2
Interesting. The way every GFI that I am aware of works, it shouldn't matter if you had 30 GFIs in series. They just look for any slight current difference between the two hots and trip if it is measured more than a few mA as that would indicate the current is going elsewhere where it shouldn't. Oh wait, I guess on a 14-50 you'd have to take into account any current on the neutral. I have no idea how a GFI would handle that. I guess I'll just shut my pie hole since I don't know what I am talking about here. LOL
 

Bokonon

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#3
Whoever just answered "Often fails, completes 60-79% of the time"... can you please elaborate on your experience with these failures? Has charging consistently failed at this rate over the course of your Tesla ownership, or has the failure rate gotten worse/better over time? And have you had any conversations with your electrician and/or Tesla about the issue?
 
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#4
I was warned by the electrician that the GFCI may trip with the UMC (they do a lot of installs for Tesla), however I have not had any such occurrences. I’ve left the UMC plugged into the 14-50 at all times.

Our county now requires the use of GFCI for EV charging. Our 14-50 is in the garage (dry location).
 

M3OC Rules

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#5
I was warned by the electrician that the GFCI may trip with the UMC (they do a lot of installs for Tesla), however I have not had any such occurrences. I’ve left the UMC plugged into the 14-50 at all times.

Our county now requires the use of GFCI for EV charging. Our 14-50 is in the garage (dry location).
I was told the same thing by an electrician who does a lot of installs.
 

TimKraynak

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#6
Hmmm. Got my first "charging interrupted" message after 5 minutes of scheduled charging last night. My case is a bit different: Mobile Connector, NEMA 14-50, but no GFCI. I have only charged the car 5 times so far. I know this is not the criteria for the post, but thought I would add my 2 cents.
 

kort677

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#7
in over 4 years of having this sort of set up I've never had a failure, the problem must be unique to the OP, his system is
probably not wired correctly
 

RocketRay

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#8
Never had an issue charging at home. Had my entire electrical panel redone for the Tesla (old panel was full, and Zinsco). New circuit works great, I charge just about every night and I always get 242-248 miles (80%).
 
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#10
Upgraded to v9 (36.7) this morning and now getting immediate GFCI trip each time charging starts. In the past 2.5 months have only had 2 charging failures. Research to be performed but expect it will result in call to electrician.
 
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#11
I've never had a problem. I also did not need a sub panel to install the new 50A breaker. I wonder if having a sub panel could be a factor ?
 

choney22

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#12
Had my electric work done in September, upgraded panel from 100 amp to 200 amp and have a dedicated 50 amp breaker for my outdoor outlet (NEMA 14-50), with GFCI. Picked up my car Friday and the three times I have plugged it in, the breaker has tripped after about 15 minutes, 45 minutes, and 40 minutes respectively. I have a call to the electrician to come by Wednesday, anyone else who has had this problem have you had a successful fix to it?

I note above someone mentioned taking the GFCI off and that solved it, not sure if code in my locale requires it or not. Will inquire with the electrician. Has anyone just swapped out the GFCI brands with success? Someone mentioned maybe doing that on another thread but no idea if that will be successful or not.
 

Toadmanor

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#13
@choney22 When I first put in my 50AMP 14-50 it was run off a 50AMP GFCI breaker. It would trip randomly after various charging times. It drove me crazy. I finally swapped out the 50AMP breaker with GFCI to just a plain (non GFCI) breaker. It has been working without ever tripping again for several months now. I do not know why it tripped previously but many said the GFCI implementation in the car does not play nice with GFCI in the breaker circuit.

Good luck.
 

choney22

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#14
@choney22 When I first put in my 50AMP 14-50 it was run off a 50AMP GFCI breaker. It would trip randomly after various charging times. It drove me crazy. I finally swapped out the 50AMP breaker with GFCI to just a plain (non GFCI) breaker. It has been working without ever tripping again for several months now. I do not know why it tripped previously but many said the GFCI implementation in the car does not play nice with GFCI in the breaker circuit.

Good luck.
Great thanks for the tip. I called electrician who will come check it all out Wednesday, and I called Tesla support just to see if they had been getting reports of this and recommended fixes. The person I spoke with stated he had heard this being an issue and that taking out a GFCI breaker would likely resolve the issue but he also offered/insisted to have a Tesla Ranger contact me to schedule a visit so they could ensure it was not anything with the car or cable and that those pieces were all working properly. Have not received call from Ranger to schedule that yet, but top notch effort on service from Tesla.
 

choney22

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#16
Had my electric work done in September, upgraded panel from 100 amp to 200 amp and have a dedicated 50 amp breaker for my outdoor outlet (NEMA 14-50), with GFCI. Picked up my car Friday and the three times I have plugged it in, the breaker has tripped after about 15 minutes, 45 minutes, and 40 minutes respectively. I have a call to the electrician to come by Wednesday, anyone else who has had this problem have you had a successful fix to it?

I note above someone mentioned taking the GFCI off and that solved it, not sure if code in my locale requires it or not. Will inquire with the electrician. Has anyone just swapped out the GFCI brands with success? Someone mentioned maybe doing that on another thread but no idea if that will be successful or not.
@choney22 Let us know what you learn from both your electrician and Tesla Ranger.


No contact with ranger yet but my electrician came by yesterday and swapped out the GFCI breaker for a standard one and I was able to charge last night without it tripping so looks like that was the problem for me.
 
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#17
No need to install a GFCI breaker, as the EVSE will have internal protection against a shock hazard. Additionally, the National Electrical Code (Article 625) does not specifically require GFCI for EVSE (Electric Vehicle Supply Equipment).