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PSA. Another melted NEMA 14-50 receptacle

Discussion in 'Charging Standards and Infrastructure' started by Kalex, Aug 23, 2018.

  1. Kalex

    Kalex Member

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    Just a reminder to make sure the UMC is snug when plugging into the outlet.
    There shouldn't be any play when plugged in. If you don't have the Tesla recommended NEMA 14-50, (Hubbell/Cooper), minimize plugging and unplugging the UMC.

    This outlet was installed about a year ago, the loose connection between the adapter blade and the outlet caused the adapter to melt into the receptacle. The circuit breaker save the day.

    Hope this helps someone.
     

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  2. BestHand

    BestHand Member

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    I recently installed NEMA 14-50 in my garage, and garage is under my living room. Waiting for delivery (Sep18-Nov18) to try it out. Will check often for any signs of burning. To make circuit breaker save the day there should be overload, short circuit for example. The danger is that the melting happened because of the bad contact while current is still below 50A.
     
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  3. nwdiver

    nwdiver Active Member

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    That's weird. Did you get any charging errors from your car? The car should be able to sense a problem as a drop in voltage and stop charging. It's unlikely your circuit breaker was much help since as @BestHand mentioned a circuit breaker only trips if current exceeds its rating. If you have a high resistance connection it doesn't take much current to melt the outlet...
     
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  4. Malbrough

    Malbrough Member

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    Typical loose connection. Put some staaaank on it when tightening the screw next time.
     
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  5. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Well-Known Member

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    Thanks for the post.

    I'd say that the above is really important.
    Everybody who gets a plug-in should have a dedicated EVSE for home charging, whether plug-and-socket or hard-wired, and then have a portable.

    A UMC bundle is $300. That's cheap, even for a 32A EVSE.
     
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  6. TexasEV

    TexasEV Well-Known Member

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    Most people have no need for both. You only need to take the UMC with you on out of town trips. Leave it plugged in at home otherwise.
     
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  7. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Well-Known Member

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    For $300 you essentially eliminate the risks from socket wear or not securing the plug, you always have your portable EVSE with you, and you have a back-up if your primary EVSE fails.

    To me it's a combination of safety, insurance and convenience and worth the relatively small one-time payment. People pay more every year for cellphone convenience.
     
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  8. azdryheat

    azdryheat Member

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    Just went and checked mine. Had a Tesla recommended electrician install mine and it says Cooper on it. Also went online and see that Leviton sells for a fraction of the Cooper outlets.
    Wonder if this failure was the outlet, or the wire not being tight when installed?
     
  9. Lloyd

    Lloyd Well-Known Member

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    Buy the 14-50 made by Hubbell. It is made much better. Costs 5X that of the Leviton.
     
  10. eprosenx

    eprosenx Member

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    Wow, thank goodness that did not result in a house fire!

    I wonder if the circuit breaker saving the day was because it eventually shorted hot to ground or to neutral or to the other phase and that blew the breaker?

    Was perhaps the UMC not plugged in all the way perhaps and just making slight contact?

    Was this a UMC Gen 1 or UMC Gen 2? I would think the heat sensing in the new UMC Gen 2 should have caught that and stopped charging?
     
  11. Kalex

    Kalex Member

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    Gen 1
    It now take some effort to plug the 14-50 adapter to the receptacle, tight fit.
     
  12. eprosenx

    eprosenx Member

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    Are you saying you put in a Cooper of Hubbell receptacle now and it is much stiffer? Which did you go with?

    The UMC Gen 1 makes sense. It draws a full 40a vs 32a and it does not have a temp probe like the Gen 2 does.

    Do you think the issue was the wire not being torqued properly down? Or was the UMC not inserted all the way fully? Or do you think it was some other internal failure of the receptacle?

    These are dangerous failures and so I think as a community we need to understand how they happen. That is good data for fire inspectors btw...
     
  13. Kalex

    Kalex Member

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    Probably caused by repeated plugging and unplugging, MS is over a year old.
    Levitton, didn't know about the Hubbell and Cooper brands. The original electrician replaced for free the receptacle and replaced the 50 amp GFCI breaker with a non GFCI as recommended by Tesla. Was causing the breaker to trip, 2 GFCI in a series.
     
  14. eprosenx

    eprosenx Member

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    Ah, so do you plug and unplug it every day then?

    Note that downgrading to a non GFCI breaker is now a code violation in 2017 NEC article 625.

    Though if it was a non-wet location I totally am in the no-gfci breaker camp.

    The new rule is not well known by most inspectors and is commonly not enforced.
     
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  15. Kalex

    Kalex Member

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    From Tesla.
     

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  16. Mishakim

    Mishakim Member

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    Tesla can say the GFCI is not required, but the Code says it is. Code wins. For wired equipment, code may defer to manufacturer specs, but this is just an outlet, code can't be based on what you say you're plugging into it. Note this is only for states that adopted the 2017 code already and didn't amend out this requirement.
     
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  17. Darthdaddy

    Darthdaddy Member

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    Did my own set up inside the garage and used 6 gauge wire with Hubble NEMA 14-50. In addition bought the NEMA 14-50 plug adapter for my Gen 1 mobile charger. Leave the adapter plugged in all the time. Plug and unplug the mobile charger. Used a Cooper at our second home with 6 gauge wire. Don't use it as often so plug and unplug from the receptacle. Difference is the Hubble posts are brass coated steel. Just bought another Gen 1 MC. Leave one at home and keep the other in the car.
     
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