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My NEMA 14-50 nearly caught on fire Friday night!

Discussion in 'Model S: Battery & Charging' started by Brunton, Oct 30, 2016.

  1. Brunton

    Brunton Pontificating the obvious

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    Saturday morning I got up to find that charging was interrupted overnight. I went to the garage and was hit with that burning electrical odor - very strongly. I unplugged the charger from the wall (it took a bit of doing), and saw that one of the side-by-side prongs had plastic from the receptacle all over it.

    I didn't plug in last night. Today I removed the receptacle from the wall and found that the unit was partially melted! It had gotten so hot that the upper screw holding the receptacle in the box even discolored. That explained why the top screw was partially out of the wall, too - it had melted the plastic threads in the box and pulled out.

    Here's what it looked like when I pulled the receptacle:
    2016-10-30 Melted NEMA 14-50.jpg
    Obviously the black conductor got extremely hot at the plug.

    You can see that it was stuffed into a standard single outlet / switch box, and there was absolutely no slack in the wires. I had to pull like a son-of-a-hmmm to get the outlet out, and it pulled the wires off the terminals in the process. Not exactly a per-code installation, I think.
    The installation was done by the property manager's electrician.
    Now I'm stuck on 120V-15A for the next few weeks until I move.
    I'll be having a new NEMA 14-50 installed at the new place - by a different electrician!
     
  2. AmpedRealtor

    AmpedRealtor Well-Known Member

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    You may wish to report this to your city, as that is obviously not up to code.
     
  3. wesley888

    wesley888 Member

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    Heat generates at the non-proper contact point. I kind of doubt the electrician didn't tighten the wire enough, but he might have used a cheapy or faulty socket. Mention it to your next electrician and hope he get a better quality one for you.
     
  4. Brunton

    Brunton Pontificating the obvious

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    That thought crossed my mind. I don't think the management company pulled a permit for the work. At least there were no inspections.
     
  5. HebrHmr

    HebrHmr Member

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    What amperage were you charging at?

    I'm changing a 6-30 to a 14-50 and switching to a deeper box. You have to really force it into a standard sized box which might have loosened something up. Combine that with a cheap socket as wesley mentioned and you have a mess. At least it was a "near miss" and you and your property are safe!
     
  6. Brunton

    Brunton Pontificating the obvious

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    40 Amps.
     
  7. brkaus

    brkaus Active Member

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    That's a bit scary. Possibly the wiring wasn't tightened properly, given the small area to work.

    Did it eventually trip the breaker?
     
  8. wesley888

    wesley888 Member

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    Without shorting out, the breaker won't trip.
     
    • Disagree x 1
  9. dhanson865

    dhanson865 Active Member

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    Well it did stop charging per the original post so either the car, the EVSE, or the breaker stopped the charge. If you say it wasn't the breaker then maybe the Tesla might have noticed a voltage drop and stopped the charging session.
     
  10. wesley888

    wesley888 Member

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    Most likely the heat melted off the contacts between the wire and the socket, and disconnected the circuit.
     
  11. Brunton

    Brunton Pontificating the obvious

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    I found the breaker tripped.
     
  12. davewill

    davewill Member

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    Replace the box with a double box. I don't believe that using the single box is even within code. You should be able to reposition the box so that you can get more slack to work with. Then you can cut off the carbonized wire, then strip and terminate it properly with a brand new outlet. Or any competent electrician can do it. Just don't call out the guy who did THAT one.

    P.S. I just reread and saw that it is not your place, and that you're moving. Someone should at least cap off the wires and put solid cover plate over the box, so I'd call the Manager.
     
  13. Brunton

    Brunton Pontificating the obvious

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    To my surprise, the property management company is sending someone out to "look at" the outlet today. I'll know tonight whether or not the bad installation is replaced with a new, proper one.
    Meanwhile, I had to run all the way to Santee, SC (50 miles) to supercharge last night. The 3 mph overnight charge wasn't quite keeping up with my daily usage. We had a nice dinner at Clark's Inn while charging, though.
     
    • Like x 1
  14. DarkMatter

    DarkMatter Member

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    A single deep box should have enough volume, just. This is clearly not a deep box.

    I still wouldn't install in that as the box would be absolutely stuffed.
     
  15. ddimit

    ddimit Member

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    I'm not a fan of plastic boxes in high current applications. I prefer metal with proper strain reliefs. these boxes were made for 15-20 amp lighting and plug applications. Not high current 240V.
     
  16. Brunton

    Brunton Pontificating the obvious

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    The outlet is replaced and working. I don't know if it was the same "electrician" or not, and I didn't see the installation as I was at work. I don't think I want to see what the new wiring looks like, either. Two weeks and I'm out anyway, so I'm surprised the receptacle was actually replaced.
    I limited my charger to 20 amps to reduce the risk of another problem.
     
    • Like x 1
  17. GJ79

    GJ79 Member

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    their bisquits are too die for and worth the trip :)
     
  18. scottm

    scottm Active Member

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    #18 scottm, Nov 3, 2016
    Last edited: Nov 3, 2016
    There's different qualities of 15-40 receptacles.

    Since this is your main way of charging the car, a daily use, and a continuous load... get the more expensive option with durable contacts and is more heavy duty... Hubbell makes a good one.

    Don't get the Home Depot / garden hardware variety store "stove receptacle" that contractors buy ... stoves get plugged in once, or twice in the their lifetime. Not daily.

    You want great brass on brass mating surfaces when those pins go into the receptacle. Any twisted alignment, weak spring, or burred edges, etc.. anything that prevents full face to face contact of conducting surfaces is going to reduce current flow area and heat up at those points. A la what happened here.
     
    • Informative x 1
  19. DarkMatter

    DarkMatter Member

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    You also shouldn't need to plug it in every day. No need to remove the UMC unless you're going on a trip. You won't need any sudden charging locally, and if you do it's likely to be J1772 anyway.
     
    • Helpful x 1
  20. Weezer Fan

    Weezer Fan Member

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    Glad there was a happy ending to your story. Sounds like the PM company did a good job getting it taken care of. They don't want their building burning down!
     

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