Is this still the original UMC with your sig, or is this a replacement?
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.
Here's some more photos, I agree, it appears the heat was coming from inside the socket. Jack (Dallas SC Manager) did a great job of dropping by a replacement (with the shiny faceplate!) within a day, he'll be taking the melted unit to the factory today for further analysis to determine whether it's a warranty claim or if I need to pay (and go after the electrician).
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Is that a 6/3 cable or 8/3 cable? 8/3 might be too small and might not be safe...
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.)
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:
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There is some very noticeable melting on the right pin in this picture. There is some barely noticeable discoloration on the left pin.
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.