14-50 Home charging breaker disconnecting

[Xcountryman]

I have a 50A installation with 14-50 adapter connection using the mobile connector for Model Y charging. The breaker frequently disconnects after charging starts and sometimes as charging begins. Often I'm sleeping and do not discover until next day and find out I have no charge. My app is set at 32A (limit of mobile connector) which I set manually ahead of charge time.
Why doesn't the Y charging regulator manage current at 32 A to keep breaker closed?
Should I set the app current limit below 32A?
Is my breaker faulty?

 

[Sophias_dad]

Your breaker is probably faulty, or the wires connected to it's lugs are not tight.

The UMC can't take more than 32A even if it wanted to. You can also look at the charging screen to see what it is using.

 

[Tronguy]

OK, a couple of questions.

First: How long have you had the setup? Brand new? Or has it been, I dunno, working for a year, but now it's giving you a bad time?

Second: Who installed it all?

Next, comment time. This is called, "Guessing madly". As in, "What could possibly go wrong?"

None of the following could be the problem. It's just wild guessing.

1. Dead on delivery breakers happen. Just like the lone lightbulb one takes out of a case of them that burns out the first time one turns it on. It happens.
2. In U.S. homes, there's two hots that are, each, 120 VAC to neutral. And/or safety ground. The two hots are 180 degrees out of phase with each other, so, hot-to-hot, it's 240 VAC. If you look at the breaker in your breaker box, it's a ganged dual breaker. Each of the individual breakers is 50A.
3. Having said all that: All one needs to get what you're getting is a short between either of the hots and neutral or ground. Or between the two hots.
4. So, if there's a short, where might it be? In no particular order:
   1. The NEMA14-50 could be a Home Depot special. These are known not to last long. Let the metal or plastic in one of these break and/or fail, and things might touch things that shouldn't be touched. Kapow and game over.
   2. In many sockets, there's a screw that holds down the wires back there. Sometimes, screws don't get tightened down correctly, or get loosened. Especially if the wire is not solid, a lone thin wire might escape and Touch Something Else. Kapow and game over.
   3. Wire. Not likely, but: Rodents are known to chew on wire. Not good and might lead to a short.
   4. Wire. How sure are you that the installer put in the right grade of wire? Overheated wire chars things, charred insulation doesn't insulate, and ka-pow, game over.
   5. Tesla Mobile Connector. These... have been known to fail. Fail with an internal short? Why not? Swap out with another TMC to check.
   6. The Car. Lots of electronics in a car. Sometimes that electronics fails. A potential test: Take the car, the TMC, and the adapter and all to another NEMA14-50 somewhere and see if that blows somebody else's breaker.

But wait, there's more! Get your hands on a clamp-on ammeter. (Or find an electrician willing to work with you who (a) has one and (b) has the expertise to use one, with malice aforethought.) You're saying that this pop-of-the-breaker is pretty blame reliable. What that says to me: If it's not the breaker that's bad, then you're probably running current pretty blame close to the actual breaker rating. When one does that, the general rule is that the breaker doesn't pop right off, but pops after a while. Or maybe something gets warm, expands, something hits something, and the ka-pow strikes.

So, get the breaker panel off so one can see the wires going into the duplex breaker. DON'T DO THIS IF YOU'RE NOT USED TO WORKING WITH HIGH-POWER ELECTRICS!!!. With the TMC not plugged into the socket, first check with the clamp-on ammeter that both hots have zero current. If you've got current with nothing plugged into the socket, well, don't go any further. Turn off the breaker, verify no voltage on the hots, and start troubleshooting with an ohmmeter to the hots and/or grounds.

Plug in the TMC, but don't plug it into the car. Check with the clamp-on ammeter if there's any current on either of the hots. 50 mA is OK, I guess, but if you've got amperes with the car not plugged in, stop: The TMC has a problem.

Using the app or the control panel, prevent the car from charging. Plug the TMC into the car. Check for amps on the hots. If you've got amperes and the car's not charging.. and not running the air conditioning, or trying to heat the battery, there may be a problem with the car. Further, if you have current, one should have the same current on both hots. That is: If you've got 5A on one hot and 10A on the other, something's wrong - it should be the same, and implies a path to ground or something that shouldn't ought to be there.

Now get the car charging at 32A. Using that clamp-on ammeter, check for equal current on both hots. If you've got 38A on one and 32A on the other, there's something wrong.

Now, if a combo of the TMC and the car shows something wrong, it's unknown whether it's the car or the TMC. Or both. But at this point, if I were you, document everything and get busy with the mobile app for an appointment with a Tesla Service Center, and let them sort it out.

Honestly don't know which fault you've got. My gut reaction is 60% probability with the wires/socket/breaker, 20% with the TMC, 20% with the car, but that's just me guessing at a distance.

Finally: I'm electrically inclined. The above stuff I know how to do and have done, and I've messed with stuff from 0.9V to a couple of thousand. As part of the work I do and have done. I'm not an amateur. If you're the kind of guy who thinks twice about putting in a 120V socket, get an electrician. Really.

 

[exxxviii]

Ditto first post. Occam's razor. Replace the breaker first.

 

[L_Mont]

Is your 50 Amp breaker a GFI breaker? A GFI breaker has a test push button on it.

 

[ATPMSD]

@Tronguy offered a lot of good information and good advice. Here are some first steps I would take:

1. If the 14-50 outlet is a Leviton of another cheap outlet replace it. You need a Bryant or Hubble outlet which will run you $80 or so. Even if this is not the current problem, a cheap outlet will eventually be a problem.
2. Check to ensure the connections at the outlet are tight. It is not at all uncommon for them to loosen up a bit as the seasons change during the first year. Trip the breaker before opening the outlet, of course.
3. If the breaker in the panel is not a GFCI breaker it needs to be replaced. GFCI breakers are required by code. Test it as suggested by @L_Mont
4. If everything is good so far, the next thing I would do is open panel and ensure the two hots, neutral and ground wires are connected as they should be. I would then ensure all connections are tight (trip the breaker before tightening the two hots connected to it) but, as suggested by @Tronguy, don’t tough anything in the panel unless you are comfortable doing so.
5. If you are still having a problem follow the additional advice offered by @Tronguy.

 

[Xcountryman]

All good pointers. My home installation is two years old. Worked well for most of that time. Recent breaker problems. Have some more troubleshooting to do. Breaker is a GFCI but I am suspecting a faulty one. After several resets this evening it charged up successfully. Thanks to all of you.

 

[1965Falcon]

Ditch the GFCI unless it's outside and required by code, to many issues with those and they have a limited number of triggers.

 

[L_Mont]

I had many time the GFCI breaker trip when it was humid and then car charging port was wet from the rain. I sprayed silicon lubricant on the charging connector and the charging port. I removed the excess spray with a paper towel.

The silicon spray lubricant does not conduct electricity (better than air) and is hydrophobic. Some GFCI breaker are very sensitive to leakage.

 

[davewill]

Ditch the GFCI unless it's outside and required by code, to many issues with those and they have a limited number of triggers.

Modern code requires GFCI on EV charging outlets. While there are a few places still using older code, the fact that the GFCI breaker was installed suggests the poster's locale probably requires it.

 

[TheLex]

I have a 15 amp AFCI breaker that keeps popping. It turns out this was caused by the heat of the combo breaker on the buss bar across from it. The combo breaker apparently wasn't making complete contact with the buss, causing arcing. When the electrician pulled the breaker, we could see the burn mark on the bottom of the breaker where it snaps on to the buss bar. Apparently the heat of the intermittent contact was enough to cause the opposite breaker to trip.

So now we're having both buss bars replaced and converting all the combo breakers to single units where possible. Not cheap.

 

[integraguy2001]

did you ever figure out what was the issue?