I have 2-month old Model 3. I installed a dedicated 240V line (8G) with Eaton GFCI circuit breaker (50 amp) which is connected to 14-50R receptacle (Eaton). It has worked great. However, when I plugged the Tesla portable charge cable to the model 3, it tripped the circuit breaker within 10 seconds. After waiting for several hours, it charged without difficulty. This occurred 4 times and went to the Tesla Service. The technician checked the car and wrote me that it is most likely from electrical transient and suggested an inspection by an electrician. Is it a problem with faulty circuit breaker? Should I install suppressor for electrical transient?
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Tripping circuit breaker
- Thread starter Drapond
- Start date
It's probably the GFCI detecting some leakage. They can be very picky.
Some GFCI are sensitive to the EV charging circuits and may false trip. You can try a different brand breaker (that's legal to be used in that panel).
With a 50 Amp circuit you are better off with a Wall Connector. It will charge faster. You are capped at 32 amps. Wall Connector will allow you to go to 40 (80% of 50 Amps). Just switching to the Wall Connector might, by luck, resolve it. It likely has more filtering.
I would not assume it's a true leak, because it is a known issue, but it could be a new real leak too.
The fact that it later just worked is a classic symptom of GFCI just not liking that load.
A Wall Connector would be money well spent in you case and it might resolve it.
Search these forums for more info.
With a 50 Amp circuit you are better off with a Wall Connector. It will charge faster. You are capped at 32 amps. Wall Connector will allow you to go to 40 (80% of 50 Amps). Just switching to the Wall Connector might, by luck, resolve it. It likely has more filtering.
I would not assume it's a true leak, because it is a known issue, but it could be a new real leak too.
The fact that it later just worked is a classic symptom of GFCI just not liking that load.
A Wall Connector would be money well spent in you case and it might resolve it.
Search these forums for more info.
GHammer
Dark Star
Yea, the Eaton GFCI Breaker is the problem. The portable connector tests for ground by passing a small current which the GFCI sees as a leakage and trips. Put in a regular non-GFCI breaker and it will be fine.
eprosenx
Active Member
By 8G do you mean 8 gauge wire (AWG)? If so, I just want to verify that wire is in conduit? (if not, then it is not rated for a 50a circuit)
But that is unrelated to your question (I just wanted to safety check it).
We have seen this before. Some combination of the new UMC Gen 2 I think and newer Tesla's have issues with some GFCI receptacles. There is some possibility that it is due to insufficient noise filtering in the UMC/Tesla, or conversely, too much noise filtering. Apparently Noise can show up to the GFCI as leakage current, but then too much filtering can actually cause leakage current with the noise being bled off...
The second page of this thread might be very interesting to you:
Gen 2 charger ground faults
I would 100% verify the wiring job (ensure there is nowhere obvious that current could be leaking), and then I might call Eaton to get their opinion on it (perhaps you have a faulty GFCI breaker and they will send you a replacement).
But if you can't find anything or get anything figured out, I would be extremely tempted to just swap the breaker for a $10 non-GFCI version. Some folks on 120v 15/20a circuits have had success changing from Leviton to Eaton GFCI receptacles, but generally, when talking about breaker integrated GFCI's you only have one option of GFCI type to buy from your panel manufacturer. Ironically Eaton cross-rates a bunch of their breakers to be "classified" by UL as working in other manufacturers panels (so if they make a GFCI breaker in the "classified" category you could use that instead of your manufacturers unit), however, since you presumably already have an Eaton panel that likely does not help.
Where is this 14-50 receptacle located? Is it in a location that might ever get wet? If not, and it is in a dry location like a garage then I would probably just swap it to a non-GFCI and go on with life. The GFCI requirement showed up in Article 625 in the 2017 NEC code and it accidentally got adopted by my state (Oregon). They struck most of the other new code requirements for GFCI's, but they missed that one since it was a last minute "emergency change". There are a bajillion 14-50's out there without GFCI breakers (think RV parks) and you don't hear of folks dying all the time. Remember, the EVSE (UMC) has a built in GFCI, so a GFCI breaker ONLY protects you plugging in the wall end of the EVSE. Everything downstream of that (the connection to the car) is protected by the GFCI in the EVSE.
I should also note that if you got a Wall Connector (or other hardwired EVSE) then the GFCI code requirement goes away. When folks are comparing the $300 cost of a second UMC Gen 2 to the $500 of the Wall Connector it is always important to point out that a GFCI breaker is generally at least $100 more than an equivalent non-GFCI breaker.
There is also the option for you to try the Wall Connector with the built in 14-50 pigtail (only does 40a of continuous charging on the 50a circuit), but it is unclear if this would have the same nuisance tripping issues as the UMC (unsure if the issue lies in the UMC and the design is the same in the Wall Connector, or if the issue is with the vehicle itself and the EVSE just passes through the issue). The new corded Wall Connector has not been out long enough for us to get any feedback in the forums here on these kind of nuisance trip issues.
Good luck! And please report back on your solution!
I have changed the circuit breaker from GFCI to regular one. It seems working fine.
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