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Charging plug burned after 4 years of use.

Charging connector to 220v one leg burned and plastic shell melted. Just found when I bought a new Tesla to replace my old one. I think every owner using 220v home charging Accessories needs to check it periodically to make sure the safety.


  • This becomes even a bigger issue the more often a plug is inserted and removed. This is true for all plugs and connectors. However it becomes a real threat at high voltage. Yes inspecting HV connections often is truly warranted.
  • The problem is not the Tesla connector but the NEMA 14-50 receptacle it is plugged into. Very likely one of the two power connections from the wires inside the receptacle is no longer tight and that creates resistance, which when power is drawn, heats up. In the worst case it gets so hot it causes a fire! This should be fixed before using it again. The grey Tesla module has a thermal fuse if the connection gets too hot, it should disconnect.

    This problem is more common with aluminum wiring, and it's not usually qualified to connect to a NEMA 14-50 because of the likelihood of this problem. If you have copper wiring, it may be the connection was never torqued down properly.

    I've been using my NEMA 14-50 daily for almost 8 years, without a problem.
  • Agree with TeslaTap, the problem is in the socket you were plugging into, not the adapter. And you are definitely at risk for a fire. Fix this now.
  • From the looks of that adapter, you may well have an issue with your NEMA 14-50 receptacle, but in my view, there is also a design issue with the adapter. There is a reason the blades that plug into the NEMA 14-50 receptacle are so large. They carry a lot of power. Now look at the tiny pins on your Gen 1 UMC that the adapter plugs into. They are way too small for a nearly 10kW power transfer without substantial resistance heating. Even the replacement NEMA 14-50 adapter Tesla sent me (same as the OPs) in 2013 gets too hot to touch at full power. My fix was to cut the charge current back to 30A. Since we got my wife's Model 3, I charge both our cars with the Gen 2 UMC. It has much larger pins for the two adapter hot sockets and the adapter barely gets warm to the touch, which is normal.
  • I'll bet plugging and unplugging the 14-50 outlet for 4 years wiggled one of the wires loose and it arc'd. Gotta really tighten those things down, and worth taking the outlet off the wall to check the pins. Im not even going to unplug mine, i will just disconnect the mobile adapter.
  • I keep it plugged-into the 14-50 outlet all the time.
  • > @andy_connor_e said:
    > I'll bet plugging and unplugging the 14-50 outlet for 4 years wiggled one of the wires loose and it arc'd.

    I'll play devil's advocate and say that unplugging it once in a while is a good thing. The light abrasion of scraping the contacts removes oxidation. Oxidation increases resistance. Teslatap, whaddya think?
  • @barrykmd - There shouldn't be oxidation with the metal to metal contact. Consider most ovens, ranges, and dryers have connections that are left plugged in for tens of years without a problem. My house's original oven (now replaced) had been connected for about 35 years with NEMA 6-50 (3- prong). I doubt it had ever been disconnected during that time.

    @stevenmaifert - the pin connections are suitable for the current - it's just a different design. If your plug is getting hot - there is something wrong and it should be corrected. I bet the connections have come loose in your receptacle as well. It's ok to be warm, but nothing more than that.

    The metal prongs conduct heat into the Tesla plug and if hot enough may melt the Tesla portion and the receptacle.
  • The contractors who installed a dryer for one of my parents did not screw down the lugs on the dryer tight enough and one of the pole connections arced exactly as what was shown in your youtube video. I am almost certain that over time one of the wires became lose. thats probably why Tesla recommends that industrial grade $70 outlet so theres a close to zero chance the wires can get lose.
  • I had a melting blackened connector a few years ago. I noticed because the circuit breaker kept getting tripped. It turned out that the electrician who installed the NEMA outlet didn’t do such a great job. It was definitely a fire risk. I had Tesla come and fix it right. I wouldn’t mess with this at all.
  • Clearly a home wiring issue and not a plug issue. This was caused by a loose connection at the receptacle termination and nothing to do with the UMC or 14-50P adapter.
  • This thread has been extremely helpful, THANK YOU!
    I had a similar issue and would appreciate some guidance from the experts here.

    Here is video and photos what happened to my 20A 125V power outlet:
    I wonder if anyone knows what may have happened (possibly an arc as indicated here in this thread?) and if any recommendations regarding the steps I am taking - see below for details.

    For context, I have been using it for 3.5 years to charge first my e-Golf and lately my Model 3.
    The fuse started tripping over the past weeks.
    This morning I noticed a burning smell and am I glad I've decided to check it - as you can see from the link above I am lucky we didn't have a house fire.

    @"" I checked your guide Very helpful, thank you.

    Based on the guide, I have now bought this new 20A 150V outlet:
    I plan to install it and cut down the charging current from my Model 3 as indicated by @stevenmaifert_12203 - but in my case down to max 10A when charging.
  • The original outlet is not a 20 amp outlet. It is a 15 amp outlet. 20 amp outlets have a horizontal slot to the left of the neutral.
    You have heating from a connection that was not tight enough or a junk outlet that couldn't handle continuous duty. There are torque specifications for the screws on an outlet. The new one is 20 amp but the wire is still 14 gauge. Do not change the circuit breaker to 20 amps.

    I have 20 amp outlets in my garage fed with 10 gauge wire to reduce the loss of energy due to wire heating.

    I also have a 100 amp feed to my HPWC wired with 2 gauge wire. It doesn't get hot.

    After the new installation use an infrared thermometer to monitor the outlet temperature until you are satisfied that it isn't getting hot. Also measure the associated circuit breaker in the panel. It shouldn't get hot either.

    Dropping to 10 amps should not be necessary. A properly installed 15 amp circuit should be able to handle 12 amps without getting hot. Continuous duty must follow the 80% rule, 80% of 15 is 12.
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