Melted 14-50 Outlet

[SageBrush]

Nothing personal but after he's replaced the "poor quality" outlet (he installed) I would double check to be certain he TIGHTENS the contact nuts. Which I strongly suspect was the issue in the first place. I've been using a 14-50 for over two years and no issues.

I was chatting with my electrician while he was installing a 14-50 receptacle for me and I mentioned I had read about the importance of tightening down the screws. He accepted my comment in good humor, and mentioned that it is his practice to tighten them, so much so that has cracked a receptacle in the past.

I thought that was a bit of bluster but a few months later I had reason to rewire the receptacle and I COULD NOT LOOSEN THE SCREWS. In the end I had to jerry rig leverage to match his strength.

 

[qdeathstar]

I was chatting with my electrician while he was installing a 14-50 receptacle for me and I mentioned I had read about the importance of tightening down the screws. He accepted my comment in good humor, and mentioned that it is his practice to tighten them, so much so that has cracked a receptacle in the past.

I thought that was a bit of bluster but a few months later I had reason to rewire the receptacle and I COULD NOT LOOSEN THE SCREWS. In the end I had to jerry rig leverage to match his strength.

too tight isn’t good either. Every proper electrician carries his torque screwdriver and tightens to within spec.

As a professional my torque screwdriver is a high one.

 

[MD-2000]

FYI - I had the el cheapo ($9.98) Home Depot receptacle so cheap it was all one integrated plastic piece. We had the Tesla wall charger with NEMA 14-50 plug; also before we got that, used the portable charger that came with the Model 3. At one point the receptacle melted - oddly, in the same spot as the one in the photograph posted.

I replaced the plug with a new one, and then a few months later, the charger itself started dialing back, indicating the plug/feed wire from the NEMA socket was overheating. (from 40A or 32A dialed down to 15A) When charging, the power cord to the wall got too hot to touch. Telsa indicated that a Hubell 9450 was the preferred socket for a high-end application like charging, so I got one of those. (Does not fit a standard double box, had to get a slightly smaller square box - then wear out a grinder bit enlarging the hole to take a 1-1/4" conduit. )

Top end socket did not fix the problem (But I don't regret a quality socket) After further tests with the Tesla Service guy and Tesla, they determined the charger itself was defective. (Wonder why Tesla does not sell those any more?) They replaced it under warranty with a wall mount gen2. I got a NEMA14-50 power cord off Amazon.ca and hooked it up, rather than direct connect which would remove the NEMA 14-50 option. There is a GE power cord rated for 50A. The red and black are 6Ga, the neutral (white, not used) and ground (green) are 8Ga. Believe me, I made sure the whole assembly wires were firmly screwed down. I Set the Gen2 power (dial) to 40A. (The wiring to the socket is 50A breaker, 6Ga wire)

Since then, the socket box, plug, power cord, and feed to the car all remain cold to the touch at 40A continuous service. If ever the charger is a problem, I can use the portable one instead - plus I have an option to plug in any other high-power tools in my garage.

My first issue may have been "not tight enough" or it may be this sort of melt made the screw loose... Who knows. Yes, tighten everything firmly.

 

[qdeathstar]

The best way to tell if it was the installer or the device would be to back out the screw on the burned up terminal and look at the wire. If it is shiny copper where it was clamped, the installer can breathe easy. If it’s pitted, dull, or black then we know the installer done pooped himself.


I’d put money on a botched install in that picture, as the wire is melted all the way up the jacket. Also, the black wire is stripped out too far. Classic newb mistake.

 

[Ostrichsak]

The best way to tell if it was the installer or the device would be to back out the screw on the burned up terminal and look at the wire. If it is shiny copper where it was clamped, the installer can breathe easy. If it’s pitted, dull, or black then we know the installer done pooped himself.


I’d put money on a botched install in that picture, as the wire is melted all the way up the jacket. Also, the black wire is stripped out too far. Classic newb mistake.

Bingo.

Many are SO quick to blame the equipment in these types of posts. Often times their "expertise" comes from the very person who was tasked with the install in the first place who was then asked to come out and do a forensics on their own work. Of course they're going to blame the hardware! lol Like any of them are going to come to the person who pays them and say "This $10 outlet wasn't the problem, I just did half-ass work in installing it and that was the problem that almost burnt your house to the ground. Want me to do it again?" lol

I keep talking about how all of these "experts" in these forums are so quick to blame $10 outlets as the source of the problem. In almost every one I've seen the evidence supports poor installation over faulty/inadequate equipment. Don't believe me? Buy your precious Hubbell for $100 and don't land the connections properly and see if yours doesn't fail catastrophically also.

I'm not hating on Hubbell, their product or any other upgraded component but I'm trying to get people to realize that improper installation will cause ANY receptacle to fail under these circumstances. Too many people think that spending a little more on an outlet will make all potential issues go away and they can now sleep soundly at night w/o a care in the world because they spent an extra $90. That's not how electricity works.

tl;dr Proper order of importance for NEMA 14-50 install for EV use:

1. Proper installation
2. Confirming proper installation on a regular basis*
3. Upgraded components

*this includes feeling the adapter/plate cover regularly during a longer charge session as well as turning off the breaker and opening the box to visually inspect & make sure everything is secure

 

[SageBrush]

I keep talking about how all of these "experts" in these forums are so quick to blame $10 outlets as the source of the problem. In almost every one I've seen the evidence supports poor installation over faulty/inadequate equipment. Don't believe me? Buy your precious Hubbell for $100 and don't land the connections properly and see if yours doesn't fail catastrophically also.

I completely agree with your underlying point that a good installation is not a step to skip, but I do wonder how much of a safety margin a high quality receptacle gives for sloppy-ish installation. Said another way, do high quality receptacle, first time installations fail as frequently as their cousin low(er) quality receptacles ?

 

[Ostrichsak]

I completely agree with your underlying point that a good installation is not a step to skip, but I do wonder how much of a safety margin a high quality receptacle gives for sloppy-ish installation. Said another way, do high quality receptacle, first time installations fail as frequently as their cousin low(er) quality receptacles ?

"High quality receptacle" assumes that the $10 receptacle isn't adequate for this task. It is. They test them well beyond what code states in order to pass them. What they don't do is half-ass the install and then approve it for use based on that. There is no "Margin for error" when it comes to proper installation that an outlet is going to rectify. It's installed properly or it's not.

Like I said, this isn't how electricity works. If you improperly strip the insulation of the conductor and a tiny little piece of it keeps the lug from making full contact & securing properly it doesn't matter what receptacle you use. Same thing if the lugs aren't fully tightened or are over-tightened to the point of stripping... a $100 receptacle isn't going to fix this. These are common failure points I'm seeing on the "cheap" receptacles so novices spot a "trend" and rush to proclaim their knowledge on the subject by blaming the outlet. That's not the root cause in most of these. It's just that FAR more of those $10 receptacles are installed so that's why we're seeing more of them. These are the same types of people who would blame seat-belts for car crash fatalities because almost everyone who dies in a car crash is wearing one.

 

[MD-2000]

The real electrician who replaced 8Ga with 6Ga (and 40A with 50A breaker) got the wires backward. IIRC, he had neutral and red backward on the socket. So it's possible I was the one who didn't screw this red down hard when fixing the wires. (I don't remember the sequence of events now...) Anyhoo, I have 6Ga screwed down to a Hubell 9450 very firmly, and a 50A power cord from a Gen2 wall charger (set to 40A) and that power cord is screwed down firmly in the Gen2. And at this point, with 40A charging, everything feels cool to the touch.

Hint - when working on anything like this - everyone has a phone, take a pic or 10 of the wires and their placement before starting, so you can be confident which goes where.

the moral of the story is that anyone can screw up. As my carpenter buddy once said - "measure once, cut twice.... or was it the other way around?"

 

[MD-2000]

Also, in researching "high quality receptacle" it seemed the point at least one manufacturer made was their top-end socket was designed to handle frequent plug-unplug cycles (more typical in an industrial environment). of course, I mostly leave the charger plugged in, especially now it's a Gen2 wall mount, not the portable charger. So yes, if installed properly, the El Cheapo probably was adequate. However, I spent $70,000-plus on the car, then PPF, second set of rims and snow tires, weather mats... Insurance is $2000 a year. I paid a real electrician to run 6Ga cable and install a 50A breaker. I think $160 for a charger socket was probably not an onerous expense. I sleep easier.

 

[Gasaraki]

I’m not sure of the outlet brand. It was bought and installed by an electrician. When I stated that I’ve heard of the Tesla 14-50 adapters not recommended, I was quoting a post from another group where the OP quoted this statement
Richmond V. Baker

It's not the Tesla Connector. Melting issues is always an issue with the plug. For people always plugging and unplugging, the outlet get loose and overheats. I suggest you get a wall connector of any brand and hard wire it in or don't plug and unplug a lot.

 

[BritneySpears]

I have not repeated this as an experiment to give it more validity but I suspect part of some of these problems are due to the plug prongs connection to the cord wire inside the molded plug body. I have a Mustart 40 amp EVSE unit. I measured the 14-50p plug and receptacle with a infrared thermometer and the hottest portion of that connection is the backside of the plug casing. It measured at 140F and on one side. The other side was at least 10 deg F cooler. The outside of the receptacle was around 100 F.

So I cut off the plug from it's 8awg cord and spliced in a molded 14-50p plug I bought that was molded with 6awg wire. I spliced the 6awg plug wire to the existing 8awg wire that was going into the Mustart EVSE unit. The circuit btw is on a 50amp breaker with 6-2 wire (no common used to connect to 14-50r). Measured temperatures were still the same.

Next I cut that off again and replaced the plug with a clamshell 14-50r I bought at home depot, the one that's yellow and has some nice pull handles molded into it. I made sure the wire connections inside the plug were robust and tight. Temperatures measured were 90-something ish deg F. Now I was measuring the outside of the clamshell and the wire connections inside were separated with an air gap. The molded plugs would probably conduct heat out to the outside of the molding much better than through air. However, the thermometer measurements at the receptacle were still around the same 90 deg F temperature. This compared to to the 100F temperature as per the first paragraph indicates to me the plug is suspect.

I'll run this experiment more thoroughly sometime and report back.

 

[Exelion]

My experience is strangely similar to the ones above: The right side of the Home Depot Leviton receptacle melted. This slowly happened after the course of two years, daily charging a 6kW rate Soul EV using a Bosch charger. The plug was only plugged in once in the beginning and never moved again, except for the day the charger stopped working because the plug melted in the back, releasing the screw.

I replaced it with a Hubbell, didn't want to take chances. Before installing, I checked the Hubbell and the Leviton to see their construction differences, and there's quite a few that stick out. I'm not going to say it is or its not the fault of the receptacle, I'll just point out some things I noticed.

The Leviton uses a screw with a phillips/flathead combo, and directly seats against the wire onto a stamped steel piece. The Hubbell uses an allen screw to push down on a copper plate, that seats the wire onto a curved copper piece. The contact point is a lot more robust than the Leviton, for sure. I think its easier to torque down an allen screw than phillips/flathead combo. Not saying it can't be done, just that one is easier than the other.

There's a lot more copper material in the Hubble than the Leviton, which seems to be using stamped steel as a conductor.

I'm positive many people out there use Leviton receptacles and charge their EV's perfectly fine. Being as cheap as they are ($11.00 appx) I think there's a lot more out there than Hubbell's and probably are charging right now without a worry. Heck, mine worked every day for two years. The Hubble has been in service now for about a year. I use a temp gun to make sure it doesn't overheat, and its temp readings never go over 80. Charging rate is 6kW.

I do wonder, however, why it seems to be the that its the right side (if the ground is on top) that melts out on just about every receptacle I've seen?