Burnt nema 14-50 plug and breaker tripped

[nwdiver]

Unless this is the weakest link in the chain, we all know the old sayin "A chain is only as strong as it's weakest link"

It's not. The UMC is definitely the weakest link. I've killed 2 and the 14-50 outlet is still standing strong.

 

[gilscales]

It's not. The UMC is definitely the weakest link. I've killed 2 and the 14-50 outlet is still standing strong.

I have only used the UMC on road trips at my brothers house, I have the HPWC installed at my home and set it to 32A as this is plenty so I really have no idea how well the UMC holds up or what is causing yours to die when others here have mentioned that they have been using them for years without issue?

 

[nwdiver]

I have only used the UMC on road trips at my brothers house, I have the HPWC installed at my home and set it to 32A as this is plenty so I really have no idea how well the UMC holds up or what is causing yours to die when others here have mentioned that they have been using them for years without issue?

Gen 1 could do 40A. The internal connections for the adapter are not very robust. Both of my UMCs melted at this point. I suspect this is one of the reasons the Gen 2 UMC is limited to 32A. Heat from current is I^2 so 40A generates ~60% more heat than 32A.

 

[gilscales]

Gen 1 could do 40A. The internal connections for the adapter are not very robust. Both of my UMCs melted at this point. I suspect this is one of the reasons the Gen 2 UMC is limited to 32A. Heat from current is I^2 so 40A generates ~60% more heat than 32A.

Makes sense, so now you are using a gen 2?

 

[nwdiver]

Makes sense, so now you are using a gen 2?

No. I have a 'hardwired' UMC. It's a Gen 1 that doesn't have adapters. It's a permanent 14-50. I also charge at 20A unless I need to charge faster....

 

[miimura]

No. I have a 'hardwired' UMC. It's a Gen 1 that doesn't have adapters. It's a permanent 14-50. I also charge at 20A unless I need to charge faster....

That's called the "Corded Mobile Connector" by Tesla.
Model S/X Corded Mobile Connector

 

[nwdiver]

That's called the "Corded Mobile Connector" by Tesla.
Model S/X Corded Mobile Connector

Figured it had a better name

 

[TexasEV]

Figured it had a better name

I call it the non-Universal Mobile Connector.

 

[gilscales]

Here is a listing for an old school Hubbell 14-50 outlet, seller incorrectly listed it as 60A but it is 50A (you can see in the pics) back then as now they still use copper on the terminal box for the hot legs

HUBBELL 60A 125v / 250v Female Plug RECEPTACLE Ceramic 60 amp Wall Mount 250 vac | eBay

 

[dhanson865]

On my second overnight charging I received an alert from Tesla app which told me that charging was interrupted. I found that the breaker tripped and the NEMA 14-50 outlet and plug burned. See the pic below.

Thanks for posting all the gorey details and pictures. These sorts of issues are common, but every new example makes it easier to convince the "oh that never happens" crowd. Maybe at some point it'll be common sense to look for these sorts of failure modes before it gets to the scorched components point of post mortem.

 

[gilscales]

The Leviton 279-S00 (Home Depot special at $9) is not the best made outlet (Even though now it is rated industrial duty) it does not compare to the 2 Tesla recommended outlets (IMO)

Just look at the contact blades of the Cooper 5754N vs. the Leviton 279-S00, also the the terminals on the Leviton do not use the clamp style for the hot legs, its just a large screw that when tightening can damage the copper wire strands because you will be applying a twisting force as the screw end bites into the wire, both brands tighten terminals to 25 in-lb. so if you really want the BEST 14-50 Receptacle then go with the Hubbell HBL9540A as they use 3/16" Allen screws for 75 in-lb. rating and have large copper V shaped lug boxes

 

[eprosenx]

The Leviton 279-S00 (Home Depot special at $9) is not the best made outlet (Even though now it is rated industrial duty) it does not compare to the 2 Tesla recommended outlets (IMO)

Just look at the contact blades of the Cooper 5754N vs. the Leviton 279-S00, also the the terminals on the Leviton do not use the clamp style for the hot legs, its just a large screw that when tightening can damage the copper wire strands because you will be applying a twisting force as the screw end bites into the wire, both brands tighten terminals to 25 in-lb. so if you really want the BEST 14-50 Receptacle then go with the Hubbell HBL9540A as they use 3/16" Allen screws for 75 in-lb. rating and have large copper V shaped lug boxes

Thanks for posting these.

So you have me at the screw terminal. I hate screws into wire. Clamp terminals are so much better.

Where did you source these from and how much were they? I need to find good cost effective places to buy the better receptacles.

 

[gilscales]

Thanks for posting these.

So you have me at the screw terminal. I hate screws into wire. Clamp terminals are so much better.

Where did you source these from and how much were they? I need to find good cost effective places to buy the better receptacles.

Someone else on this forum posted that the Cooper 5754N could be had for $12 and I was finding that hard to believe as prices tend to be in the 50$ plus range everywhere else, I used the link provided by the post and received the real deal for that price, however, I still believe that the Hubbell is far superior to the Cooper.
Here is the link to the place where I purchased the Cooper
Cooper Wiring Devices - 5754n, Straight Blade Receptacle - Dale Electric Supply Co.

 

[gilscales]

Ran across this thread and while it is not clear what the cause of this failure is I found post #13 very informative

Think I dodged an electrical fire

 

[Feathermerchan]

Those are on backorder.

 

[gilscales]

Those are on backorder.

Their site shows 3 in stock, I placed an order for 5 of these on 12/5 from the website, I received a call from them the next day informing me that they had 2 in stock and that the other 3 would have to be backordered, they asked if I would like to wait until the backordered items arrived so that it would be less for shipping, I agreed and the package of all 5 units arrived yesterday, they may be backordered but it seems they can delivery them quickly anyway, at least they did for me.

 

[Feathermerchan]

So order one and see if you get the same email I did. How on earth are you going to need 5? Or are you just reselling them on Amazon?

 

[MP3Mike]

How on earth are you going to need 5? Or are you just reselling them on Amazon?

Did you miss that he was a contractor and that he puts a 14-50 in every house that he rehabs?

 

[gilscales]

So order one and see if you get the same email I did. How on earth are you going to need 5? Or are you just reselling them on Amazon?

As @MP3Mike has stated already I am a General Contractor and just bought some stock, if you would like one then I will send you one as I do not need all of them at this time, just P.M. me and i'll send one at cost plus my shipping cost if you like.

 

[Feathermerchan]

They asked if I wanted to wait and I said yes so I'm OK with waiting.