Small Fire, NBD, right?

[Tam]

...I figured that would have disconnected...

I have no background in electricity but by reading on the web, this is my opinion:

It's quite troubling that the triple heat protections couldn't prevent the overheating problem:

1) Software that detects current fluctuations would reduce the charge rate 25%.
2) Newer 14-50 plug as pointed out by the articles you linked.
3) The built-in plug's fuse didn't trip.

What are the Ampere readouts each time you charge?

If the black wire was not torqued down, it should now be loose after such an overheating episode.

There are 3 out of 4 prongs that have burned marks:

1) The black wire one (hot wire) prong is the worst.
2) The Red wire (neutral) prong is second worst: Tesla does not use this prong. So, where's the heat from?***Edit: Sorry. See @JohhnyG below: Red is NOT neutral. Red is LOAD line.
3) The Green wire (ground) prong is the third worst.
4) The White wire (hot wire) prong seems to be intact--***Edit: Sorry. See @JohhnyG below: White is NEUTRAL.

--------------------

To prevent this from happening again in future, I would:

1) monitor the heat when charging: either using non-touch thermometer or by hand.
2) dial down the Amperes from the 17" screen display.

Or:

Hardwired HPWC.

 

[JPP]

I have mentioned this before--I do not remove/reinsert my NEMA 14-50 adapter into by NEMA 14-50R @ home. I have 2 adapters, and keep 1 in the UMC bag. If I need to take my UMC with me (....far more infrequent now with more Supercharging), I disconnect the UMC at the adapter. The wear & tear is on that connection, not the spring loaded fingers inside the NEMA 14-50R. Yes, I know that the UMC to adapter connection will fail, but it's an easier fix. And, yes, the Gen. 2 UMC now has a different system of adapters and pigtails.

 

[CA_Vagabond]

Bad connection at the outlet, bad receptacle, or a high resistance heating connection from the between the blade of the plug and the receptacle. Replace the plug of the MCU and the receptacle. Maybe also pull some new wiring to the receptacle.

 

[JohnnyG]

I have no background in electricity but by reading on the web, this is my opinion:

It's quite troubling that the triple heat protections couldn't prevent the overheating problem:

1) Software that detects current fluctuations would reduce the charge rate 25%.
2) Newer 14-50 plug as pointed out by the articles you linked.
3) The built-in plug's fuse didn't trip.

What are the Ampere readouts each time you charge?

If the black wire was not torqued down, it should now be loose after such an overheating episode.

There are 3 out of 4 prongs that have burned marks:

1) The black wire one (hot wire) prong is the worst.
2) The Red wire (neutral) prong is second worst: Tesla does not use this prong. So, where's the heat from?
3) The Green wire (ground) prong is the third worst.
4) The White wire (hot wire) prong seems to be intact.

--------------------

To prevent this from happening again in future, I would:

1) monitor the heat when charging: either using non-touch thermometer or by hand.
2) dial down the Amperes from the 17" screen display.

Or:

Hardwired HPWC.

1) It is very possible that the UMC did kick-off or reduce power due to line resistance or current fluctuations, but it's also designed to re-engage to try to keep your car charged. It will only permanently shutdown if it detects multiple failures in succession.
2) This didn't appear to be an issue with the UMC 14-50 plug adapter.
3) The thermal fuse internal to the plug may not have gotten hot enough, due to the point of failure and heat source being internal to the receptacle.

If the black load line was loose, which created arcing, which created heat, it would have caused expansion, and possibly minor arc-welding, bridging the gap. In most cases it wouldn't appear loose after an arcing heating incident. Overheating does not make a wire loosen.

** The Red Wire is not Neutral!!!!! Please, let's not kill our fellow Tesla owners!! **
Red and Black are your hot load lines.
White is your neutral line.
Green is ground.
The black load line is clearly the origin of failure. The other wires will be heat soaked and subsequently damaged due to thermal conduction and, to a lesser degree, convection. The same reason why the receptacle housing is damaged.

If monitoring temperature is a serious concern, I would suggest setting-up a wireless conductive temperature probe. It can alert you via a mobile app.

 

[plumazul]

1) It is very possible that the UMC did kick-off or reduce power due to line resistance or current fluctuations, but it's also designed to re-engage to try to keep your car charged. It will only permanently shutdown if it detects multiple failures in succession.
2) This didn't appear to be an issue with the UMC 14-50 plug adapter.
3) The thermal fuse internal to the plug may not have gotten hot enough, due to the point of failure and heat source being internal to the receptacle.

If the black load line was loose, which created arcing, which created heat, it would have caused expansion, and possibly minor arc-welding, bridging the gap. In most cases it wouldn't appear loose after an arcing heating incident. Overheating does not make a wire loosen.

** The Red Wire is not Neutral!!!!! Please, let's not kill our fellow Tesla owners!! **
Red and Black are your hot load lines.
White is your neutral line.
Green is ground.
The black load line is clearly the origin of failure. The other wires will be heat soaked and subsequently damaged due to thermal conduction and, to a lesser degree, convection. The same reason why the receptacle housing is damaged.

If monitoring temperature is a serious concern, I would suggest setting-up a wireless conductive temperature probe. It can alert you via a mobile app.

I agree. The black marks on the other plugs is just soot thrown off from the one that was arcing.

 

[Tam]

...** The Red Wire is not Neutral!!!!! Please, let's not kill our fellow Tesla owners!! **
Red and Black are your hot load lines.
White is your neutral line.
Green is ground.
The black load line is clearly the origin of failure....

I messed up! Thanks for the corrections!

 

[K-MTG]

Any updates from the SC...

 

[stillandbox]

Any updates from the SC...

I just got home from the SC. They already had all of the pictures I posted here...which is creepy...

They will be keeping the car for the “unforeseeable future” after looking at the car for about 10 minutes (I also have other issues such as awful wind noise & need my display replaced, so that may play a roll in the stay also). Currently have a Cadillac loaner :-(

 

[SMAlset]

I just got home from the SC. They already had all of the pictures I posted here...which is creepy...

They will be keeping the car for the “unforeseeable future” after looking at the car for about 10 minutes (I also have other issues such as awful wind noise & need my display replaced, so that may play a roll in the stay also). Currently have a Cadillac loaner :-(

Update?