NEMA 14-50 Plug Meltdown / Near Fire

[dsgerbc]

There is a thread here where someone purchased all the different manufacturer versions they could find and compared them. Leviton was by FAR the worst.

Is this the one?

 

[Snerruc]

I had a similar experience to op. Do not trust Tesla’s recommendations for electricians. I used one and he screwed up about as bad as can be done. It had to be completely redone after the plug and receptacle fused. And melted.

 

[eprosenx]

Is this the one?

This one:

Definitive 14-50 NEMA Outlet Guide

I have been buying the Bryant one from Zoro since it is good quality and relatively cost effective.

 

[nwdiver]

How did you come to own a Gen 1 UMC? IMO that's probably the culprit. I've had two of those die on me... I suspect that was one reason the Gen 2 is 32A. What current were you pulling when it died?

 

[SSedan]

If it were the Gen 1 itself that failed I don't think it would have shown up as a loose wire.
IMO the Gen 2 is 32amp since some 14-50 are only 40amp installs.

Isn't Canada's continuous loaf limit below the USA 80% too? This allows one PN.

 

[mswlogo]

That is a UMC 1 adapter not third party.

It would not had been so severe if it was a UMC 2. It would have sensed it and not pulled as many watts.

For the record I hate 14-50 outlets period for charging. Especially if using adapters or extension cords.

Be careful that the cables are fully seated in on the wall connector before cranking down on them. It’s tight quarters and hard to confirm your all the way in. Especially if you use the riser block.

 

[Uncle Paul]

Good idea to put your hand on your plug connection from time to time during a charge. The connector may be warm, but not so hot you pull your hand quickly away.

This is one ot the reasons that Tesla offers their own reasonably priced wall mount.

Worth buying a good quality 14-50 connector when you are doing your original installation.

 

[nwdiver]

If it were the Gen 1 itself that failed I don't think it would have shown up as a loose wire.

Sure it would... the poor connection in the UMC generates heat. There's physical contact between the UMC and the plug (I hope). Metal conducts heat pretty well. Everything heats up, expand, loosen and some things melt.

 

[Jaywlker]

How did you come to own a Gen 1 UMC? IMO that's probably the culprit. I've had two of those die on me... I suspect that was one reason the Gen 2 is 32A. What current were you pulling when it died?

I believe 40 amps.

 

[nwdiver]

I believe 40 amps.

Since my 2nd UMC died I always charge at ~20A unless I need more. 20A is more than enough ~95% of the time. The heat generated from current is squared so 40A generates 4x as much heat as 20A.

 

[SMAlset]

I'm glad that nothing more serious happened!

Note that plugging the UMC directly into the outlet rather than using the 3rd party adapter (what kind was it?) might have prevented this, since the UMC has a thermal cutoff sensor.

Instead of the HPWC we went with a NEMA 14-50 and instead of using the mobile with adapters we bought the corded 14-50 mobile connector. So are you saying that's a safer way to have gone?

 

[SMAlset]

Curious OP were you ever seeing any of the status lights indicating a problem?

BTW as mentioned we have the corded 14-50 mobile connector which we bought around the time we bought our Model S (so maybe 3/2017 or 4/2017). Even though we both use it to charge our cars (MS and Model 3) we have dialed down the amps in our scheduled charging to I think 29-30A. It takes a little longer but it still fully charges even my Model 3 LR (310mi) to 90% by morning and starting from 20% (use the 11pm - 6am PG&E plan for cheapest rate).

 

[nwdiver]

Instead of the HPWC we went with a NEMA 14-50 and instead of using the mobile with adapters we bought the corded 14-50 mobile connector. So are you saying that's a safer way to have gone?

I've been using the 14-50 mobile connector for >2 years now and it seems A LOT more robust than the v1 UMCs. The connection point for the adapters was very minimal. Even charging @40A for hours on trips my 14-50 MC doesn't get very hot.

All the fuss about different brands of 14-50 outlets is almost comical. Current is delivered to your car in a chain... from the breaker to the wire to the outlet through the UMC to your car. Just like any chain it's only as good as its weakest link. A $10 Leviton might be brass and the $80 Hubbell... slightly stronger brass.... but the v1 UMC was a EFFING paper clip. Upgrading the brass link isn't going to make the chain stronger if one of the links is a paper clip!

 

[Lloyd]

Buy the Hubbell 14-50r when you replace it. It is much better built.

https://www.amazon.com/Hubbell-253-1454-HBL9450A-Receptacle/dp/B000J15QW2

The difference in price is dramatic. Amazon has the Leviton listed for $8.15. The Hubbell is $102.50. I believe I paid in the $60 range several years ago.

 

[nwdiver]

Buy the Hubbell 14-50r when you replace it. It is much better built.

https://www.amazon.com/Hubbell-253-1454-HBL9450A-Receptacle/dp/B000J15QW2

The difference in price is dramatic. Amazon has the Leviton listed for $8.15. The Hubbell is $102.50. I believe I paid in the $60 range several years ago.

Do you really think that's the weakest link in the electrical chain?

 

[Eno Deb]

Instead of the HPWC we went with a NEMA 14-50 and instead of using the mobile with adapters we bought the corded 14-50 mobile connector. So are you saying that's a safer way to have gone?

Not sure how you're jumping to that conclusion. The wall charger obviously has one less contact surface for the current to travel through, but as long as your outlet is in good working condition, the corded mobile connector will be fine. It also has the same temperature sensor in the plug as the UMC gen2 adapters.

My comment was referring to things like extension cords and 3rd party adapters (that some people use if they don't have the right UMC adapter for their outlet). Those effectively defeat the temperature sensing capability of the UMC since the sensor is no longer in direct contact with the outlet.

 

[Rottenapplr]

View attachment 416959 View attachment 416958 View attachment 416954

My main house breaker tripped tonight. Upon investigating, I saw black smoke curling up my garage wall and smelled burning plastic, from where my 14-50 plug is located. Turns out my electrician had installed the plug with a loose black conductor, causing the outlet and plug to meltdown. At this point I am much more relieved than upset because I was able to stop what could have been a disaster. I will be double-checking every connection myself going forward in the install of a HPWC to replace the 14-50! If you smell burning plastic, investigate!

Did you get the work inspected by the city for a permit after the install?

 

[eprosenx]

Buy the Hubbell 14-50r when you replace it. It is much better built.

https://www.amazon.com/Hubbell-253-1454-HBL9450A-Receptacle/dp/B000J15QW2

The difference in price is dramatic. Amazon has the Leviton listed for $8.15. The Hubbell is $102.50. I believe I paid in the $60 range several years ago.

The Hubbell is definitely the best quality receptacle I am aware of, but it is stupid expensive. I have been buying the Bryant one from Zoro.com which is very nearly identical. They are made by the same company now.

See the link I posted above for comparison pictures side by side.

 

[ucmndd]

Do you really think that's the weakest link in the electrical chain?

Yes.

 

[mswlogo]

Buy the Hubbell 14-50r when you replace it. It is much better built.

https://www.amazon.com/Hubbell-253-1454-HBL9450A-Receptacle/dp/B000J15QW2

The difference in price is dramatic. Amazon has the Leviton listed for $8.15. The Hubbell is $102.50. I believe I paid in the $60 range several years ago.

The weakest link is having an outlet at all. He said he plans to install a Wall Connector, which is the right move.