UMC very hot to the touch

Warm is normal, but hot to the touch is not! Best to leave the amps dialed way down and call the service center. They should then replace it for you.

SeminoleFSU said:

Thanks Chris. This is what I figured. Do you know if there's ever been a published nominal temperature threshold spec for the UMC's? I have a couple friends with handheld temp sensors that are in the restaurant and HVAC biz who might let me borrow theirs to shoot the UMC while charging at 40amps to get some more exact numbers outside of "scalding to the touch"

Click to expand...

The brick has a temp sensor built into it that automatically lowers the current, so that portion shouldn't be scalding hot. I'm guessing that you are talking about the 1ft wire section along with the UMC end. When that joint fails, it gets hot, and eventually melts the adapter end. Tesla service will replace it if you let them know.

I'm not aware of an official spec, but I'm sure there is. Probably X amount of degrees above ambient temp. All I can say is being warm is normal and nothing to be worried about (there is a lot of power going through there after all). But hot to the touch is bad and indicates a failure. Fortunately there doesn't seem to be much in between (such as really warm, or only too hot after a while).

I personally wouldn't mess with it, warm is normal, hot is not, period. known issue, known burn and f1r3 hazard. my advice to anyone who encounters this would be to unplug the car end immediately, which should not be hot and will stop the flow electricity... and call Tesla ASAP!

And you also might want your electrician to check out the house wiring. Loose connectors can also be the culprit.

Definitely verify that all connections are plugged in well and solid. If you are comfortable working with electrical, you can also CUT THE POWER TO THE CIRCUIT through the circuit breaker, verify the outlet is dead with an appropriate voltmeter, then open your 14-50 outlet at the wall end (assuming this is the outlet) and ensure the wire connections are screwed in solid and proper.

yesterday I plugged in the car and noticed about an hour later that the car had stopped charging. when I got home I noticed that the main circuit breaker in the electrical panel in the house where the tesla outlet is connected had tripped. once I turned it back on I went to check the umc and noticed two things:

- umc cable was very hot
- neema 14-50 plug at the end of the umc end had somehow become dislodged and was not flushed against he receptacle, it was plugged in but about 1/8th of an inch loose, you could see the metal pins in the plug a little bit

I have read about loose umc issues and am thinking that this looseness is what might have caused the overheating and the circuit tripping. does that make sense to you guys?

will continue to monitor. seems like a design with some kind of a latch to keep it from coming loose would be better.

If the UMC plug was loose in the NEMA 14-50 outlet, then you need a new outlet. Normally when plugging in and unplugging the UMC, it should take a lot of effort and will never just casually fall out. It sounds like yours is worn down and not making good contact with the plug anymore. Time for a replacement. Also, disconnect the adapter from the UMC cable and check for melting. If the heat damaged the UMC or adapter, you'll want to replace that too.

Until you get that outlet replaced, I would highly recommend reducing the amperage or better yet, switch to the 120v adapter.

ChrisPDX said:

If the UMC plug was loose in the NEMA 14-50 outlet, then you need a new outlet. Normally when plugging in and unplugging the UMC, it should take a lot of effort and will never just casually fall out. It sounds like yours is worn down and not making good contact with the plug anymore. Time for a replacement. Also, disconnect the adapter from the UMC cable and check for melting. If the heat damaged the UMC or adapter, you'll want to replace that too.

Until you get that outlet replaced, I would highly recommend reducing the amperage or better yet, switch to the 120v adapter.

Click to expand...

+220V

PLEEZE heed ChrisPDX's very sound advice! Catastrophic results could occur!

+100V from Japan: loose=danger