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mknox
Well-Known Member
I would suggest turning the amperage down on the touchscreen to the lowest you can get by with until this is resolved. I drive about 100 miles a day and can get by at 16 amps overnight. If I start charging at 7:00 PM, it's done sometime around 5:00 or 6:00 am.
A new 14-50 adapter will likely solve your problem. Call service and they'll ship you one.
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Today I could smell melting plastic as well... my UMC plug is beginning to melt at the 14-50 adapter. On my infrared thermometer it is recording 227 degrees F.
It's a replacement, but a very early replacement (the one with my car wouldn't open the charge port unless you touched it to the rear glass). So it's a part of the "known problem" children that just hasn't deteriorated to the point of melting until recently. Service center is sending one my way tonight.
I was having this problem also. I am swapping out my charger tomorrow or Saturday at the Marietta (Atlanta) service center.
Here are some pictures:
There is some very noticeable melting on the right pin in this picture. There is some barely noticeable discoloration on the left pin.
This mirrors the above picture, melting noticeable, and discoloration.
The serial number of my UMC. I didn't get a UMC with my car, the Atlanta service center gave me one of theirs which was circa early Signature cars.
Here are some pictures:
There is some very noticeable melting on the right pin in this picture. There is some barely noticeable discoloration on the left pin.
This mirrors the above picture, melting noticeable, and discoloration.
The serial number of my UMC. I didn't get a UMC with my car, the Atlanta service center gave me one of theirs which was circa early Signature cars.
Is that a 6/3 cable or 8/3 cable? 8/3 might be too small and might not be safe...
personally, I put an exterior RV NEMA 14-50 outlet inside my garage. ran 6/3 cable in conduit to the outlet box. the metal box seems safer than having a hot receptacle embedded in the drywall. very sturdy too. could probably even give it a good whack with a baseball bat without damaging it.
The HPWC uses #6 type EV cable to the car for delivering 80A, as well as internally in the HPWC. The wire used is rated at 105 degC, good to 84A.
The UMC appears to use #10, which is good for 42A at 105 degC insulation rating. It may be #8, but I don't think so.
(Note that UL listing doesn't require the 125% sizing figure for devices that have been listed and tested, so the HPWC & UMC internal wiring doesn't have to be bigger. Also note that #8 can be used for wiring a 14-50 when it's in conduit, but cannot be used if Romex is used - because Romex must be derated to the 60 deg C value regardless of internal insulation rating.)
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That's what I'm asking about - the wiring of the 14-50, not the charging cable wire. I'm wondering if 8/3 was used here to wire up that 14-50 instead of 6/3.
Duckjybe
Member
Same here. I just went out to the garage to check mine and sure enough it was almost too hot to touch! I am getting this discoloration around the right hand pin (as seen in the picture below) as well. I dialled down my current to 28A until this gets resolved.
For what it's worth, #8 wire will carry 40 amps without an issue, even if Romex. NEC just requires you derate it, meaning 8/3 Romex can't legally be installed. That said, the wiring wouldn't be a problem and #8 in conduit won't be an issue.
efxjim
Member
You have to tighten the screws quite tight onto the wire. I find people do not apply enough torque to make a proper connection. There are inch or ft\lb specifications for the connections listed for the recepticals. If one current carrying wire is getting hotter than the other one then a connection is usually loose. We used to have to tighten our 30A twist lock plugs every 6 months or so or they would start heating up due to lack of tightness. I think they worked loose from all the handling.
Duckjybe
Member
I took my UMC back to the Tesla Service centre in Toronto and they gave me a new one with a new 14-50 adapter. Unlike my old one, this one has the chrome cover over the button. Plugged in for 1/2 hour at 40A and it is still cool to the touch at the elbow (before it was almost too hot to touch). All is great. The cable gets a little warmer as you run your hand down to the rectangular box, but I would think the electronics in it would heat up a little so this is normal. I would recommend owners check their 14-50 connection for excessive heat.
Good information here. My 14-50 has been getting more difficult to work, have sig vehicle, finally stopped working yesterday, getting only red light. So switched to the 110v outlet to charge car overnight (that works fine) and called electrician to check garage 240v outlet next week, thinkng it was the wall socket. After reading this thread checked 14-50 and sure enough, light corrosion inside on pins. Used pen knife to scrape off, now working OK again. Like minor battery corrosion on ICE battery connections. I had noticed it was somewhat hot to touch when charging past few months. Plan to take car to Tesla service center for 6K tire rotation in next few weeks so will ask for replacement 14-50 when take to service. This is good forum, thanks.
Yup - watch it carefully. Mine seemed to be fine, but then one weekend I noticed a "warm smell" and it got worse quickly.
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