How bad is this?

[DMan]

I use an extension cord. I think some water got into the seam as the garage door was opening. That’s my only thought on how this happened. Everything still works fine so all I did was move the connection right against the wall away from any water drops that may drip from the garage door. Do you guys think I need to replace the extension cord and charger too?

 

[MP3Mike]

Do you guys think I need to replace the extension cord and charger too?

If you unplug it and take pictures of both pieces would could have a better idea of the damage. (Assuming they will even come apart.)
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I would replace the extension cord, or just the receptacle on the end, and the adapter. (No need to replace the whole UMC.)

It could have just been a bad connection that got too hot.

 

[Tam]

...replace...

I agree with @MP3Mike : Replace whatever affected, not everything else.

1) First, make sure yours is currently up-to-date with heat sensor.

2) What the amperes are you using?

 

[murphyS90D]

Which plug is that? A 14-50 or a 10-30? Tesla's 10-30 adapters were recalled a year or two ago for overheating problems.

You don't have to replace the UMC, just the adapter. The heating is caused bay a bad (high resistance) connection. It is unlikely that water caused that unless it was salt water or acid rain. Water with no extraneous ions is not a good conductor.

The extension cord is done for. Is it rated for a high number of plug insertions without losing the spring tension in the contacts?

 

[DMan]

It’s a 14-50. I got the plug from Amazon about a year ago and have left everything plugged in since Day 1. I think the extension cord costs about $80. Everything still works but you guys think I should definitely still replace the extension? I can plug directly into the wall but it barely reaches the car (I keep it parked outside).

 

[Tam]

It’s a 14-50...

You might want to decrease your amperes to reduce heat and only increase to its standard setup when you are in a hurry.

 

[gsteele]

There’s a reason why the 2nd generation UMC maxes out at 32 Amps. The gen 1 14-50 seems to be marginal at 40 amps. I’d replace at least the 14-50 adapter. If anything looks discolored in the slots of the drop cord, I’d replace that end too.

 

[brkaus]

I’d replace the adapter and the cord. I’d hate to burn the house down over $140.

Something caused high resistance and heat, I doubt it’s related to the water.

Consider 32a charging when possible with the cord. It’s roughly 1/2 the heat because it’s a squared function of the current.

 

[iCharge]

It’s a 14-50. I got the plug from Amazon about a year ago and have left everything plugged in since Day 1. I think the extension cord costs about $80. Everything still works but you guys think I should definitely still replace the extension? I can plug directly into the wall but it barely reaches the car (I keep it parked outside).

I agree with others that only the 14-50 plug on the damaged end needs to be replaced. Depending upon length You have You can cut the damaged end and Replace that with the new 14-50 female plug like this Which is rated for up to 50 A
https://www.amazon.com/Camco-55353-...3HVV4MVTJ54&psc=1&refRID=1N9TTETR63HVV4MVTJ54

It goes without saying that you should follow all general precautions of wiring. More important than the 50 AMP rating is the fact that you should not have any connections that are remotely loose - at all on that end. Loose connections mean higher resistance And that leads to Conversion of electrical energy into heat energy.

happy charging !

iCharge

 

[thegruf]

Copper is a very good conductor of heat.

I would be wary the the heat has not damaged the connector between the UMC and the adaptor.
Check the UMC end very carefully when you remove the adaptor for signs of heat damage.
Any sign of discoloration at all I would change the whole UMC cable, expensive yes, but cheaper than your house.

Firstly though I woudl talk nicely to Tesla, it may well be that they will change the UMC as warranty/good will.

 

[yobigd20]

if your cord is 'hanging in the air' it will put too much pressure on the plug's connection points (umc adapter, 14-50 to external adapter, and plug in the wall) causing one or more (or all) of those connection points to overheat and melt and possibly start a fire. you should have A LOT of slack to reduce the weight pulling down at the connection points, ideally enough to be able to 'hang' the cord on something right before umc adapter in order to relieve any 'pulling' that is occurring.

 

[Rocky_H]

I'm seconding (thirding? fourthing?) replacing those two pieces, but also I do recommend about turning down the amps for your constant daily use. Those original UMCs could get pretty hot running at their maximum 40A, and for your daily use, it's usually not necessary to go that high. It's not just heat itself, but heat cycling that is hard on electronics. In other words, when it's not charging, that cord goes down to air temperature (X). Then, when it's being used, it heats all the way up to Y. So every day, it's going through a temperature change between X and Y. Metals and solder joints expand and contract with changes in heat, so the farther that temperature difference is every single day/night cycle, that's just more cumulative physical stress on the parts. So if you can turn down the amps to something like 31 to 34 amps or so instead of 40, then you can keep that temperature change between "cold" to "slightly warm" instead of "cold" to "hot". That should help the lifetime of your charging cable.

 

[eprosenx]

View attachment 375377

I use an extension cord. I think some water got into the seam as the garage door was opening. That’s my only thought on how this happened. Everything still works fine so all I did was move the connection right against the wall away from any water drops that may drip from the garage door. Do you guys think I need to replace the extension cord and charger too?

I am a little surprised I am the first person to say this here, but I would *highly* recommend that nobody charge at home on a regular basis using an extension cord. They are just extra failure points. If in a garage, I would probably just run surface mount conduit and relocate the 14-50 receptacle you have to the needed location.

I think a lot of 14-50 cords are sold with the RV market in mind where folks nearly never get anywhere near the max capacity of the circuit and if they do, it is not for hours on end like with an EV. I think 40a on a lot of 14-50's is sketch and so I suspect that was a factor in Tesla's decision to make the new UMC Gen 2 only 32 amps (among other factors).

But to pile on to what others have said, you need to replace the 14-50 adapter on the end of the UMC for sure (and it could have even damaged the UMC itself - maybe Tesla will take pity on your and replace at least the adapter for free). And the extension cord needs replaced as well. No reason to risk a fire over that. You might just get away with cutting the end off of it and putting a new receptacle on, but I would be extremely cautious of field terminated cords (and the cost of a good quality Hubbell or equivalent end might near that of a new cord).

We have seen a lot of failed 14-50 receptacles on the forums (not even considering extension cords). For that reason (among others) I have become quite a fan of hard wired EVSE's like the Wall Connector. I am crazy happy with mine. Zero issues and I charge my M3 at 48 amps. #6 AWG copper in 3/4in EMT and I sleep very well at night. ;-)

Please report back on what your solution ends up being!

P.S. And if you do end up sticking with the extension cord, it would not be a horrible idea to turn charging amps down to 32 as an added layer of safety. Note that Tesla tells you not to charge on extension cords. ;-)

 

[DMan]

I'm going to Tesla today to see what they say and also turning down the amps to 32. I've had my 2015 85D since Oct/Nov of last year. I had a 2013 S85 for a year before that and never any problems.