EVSE NEMA 10-30 plug and cable getting pretty hot - is this normal?

Discussion in 'Hyundai Kona Electric' started by BlueKonaEV, Aug 22, 2019.

  1. BlueKonaEV

    BlueKonaEV Active Member

    The NEMA 10-30 plug and the cable from the plug to the control unit gets pretty hot when I'm charging. I did check the #8 wire from the 10-30 outlet to the breaker in the panel and it is only moderately warm. Is it normal that the cable and specifically the plug can get pretty hot? My charging speed is excellent and I did check all connections and everything is tight, so assume that the heat is normal.. just wanted to check if any of you have the same experience? I have to find my laser thermometer to check the actual temperature but it definitely is pretty hot.
     
  2. Bugblndr

    Bugblndr Member

    A NEMA 10-30 is only rated to 30A. What EVSE are you using and how many amps are you charging at?
     
  3. Gjpzee

    Gjpzee Member

    I have read that 10-30 outlets are not grounded. When I changed my dryer's 10-30 to a 14-30, the electrician mentioned the ground was not connected to the 10-30. Not sure if that is the reason for the high heat though. My cable gets warm while charging but not hot.
     
  4. BlueKonaEV

    BlueKonaEV Active Member

    I have a MUSTART 26 AMP EVSE

    https://www.amazon.com/MUSTART-Port...lja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ&th=1

    Circuit has a 40 amp breaker and #8 wire from the panel to the 10-30 outlet. The outlet itself does only get moderately warm. The heat I'm observing is right on top of the plug and the first foot of the cable that goes to the control unit.. From the control unit to the car, it's not too hot at all, just at the plug..
    I double checked all the connections and they are tight..
     
  5. BlueKonaEV

    BlueKonaEV Active Member

    Correct, the 10-30 is wired to neutral, not ground. This is the correct way to wire it. As they are selling the EVSE for that plug, I assume that there should be no issues.. I went with 26 amp vs. 32 amps (which uses NEMA 14-50), because my house only has a 150 amp main breaker panel and I did not want to spend the $$$ to upgrade to 200 amp. So far, after almost 2 months of charging at home, my main breaker has not tripped yet, so it looks like I'm ok.

    My house was built in 1989, I believe that ground and neutral are bonded in the breaker panel but I'm not sure. What I've read, they were bonded in the panel on panels older than 20 years.. My panel is 30 years old..
     
    Last edited: Aug 23, 2019
  6. electriceddy

    electriceddy Well-Known Member

    NEMA 10-30 does rely on the neutral bonded to ground in the panel and in older dryers were required to bond the metal chassis of the appliance via a strap to the neutral blade. This is for shock protection only and will have no bearing on heat build-up.
    https://en.wikipedia.org/wiki/NEMA_connector#NEMA_10
    The modern version of this is a 14-30 (4 wire) which bonds to ground via a separate pin (blade).
    I am sure that your EVSE does not have that strap to the neutral blade.
    What is the temperature (and current at that temperature) exactly as the wire and connectors should have a 90 degree C termination temperature rating.
    I am not a huge fan of those old type connectors and am surprised that the EVSE came with one (can you take a close up picture?) receptacle and male cord cap.
     
  7. BlueKonaEV

    BlueKonaEV Active Member

    Here we go... 20190823_174003.jpg
     
  8. electriceddy

    electriceddy Well-Known Member

    That's what I thought. Just check temp and monitor current, who knows if the male end is crimped ,soldered or screwed in. You can always change the cord cap and receptacle if needed ( to a 14-50 seeing as you fed w/ #8s and 2P 40 o/c device)
    https://en.wikipedia.org/wiki/NEMA_connector#NEMA_14
    - I assume (without taking unit apart) that the ground on the EVSE feed cable connects to the L shaped blade and the 2 hots to the straight blades.
    The wire gauge looks correct and is rated for 105 degrees C. The part I pay most attention to is the J1772 end as an overheat there would ruin the pins on the car.
    BTW my EVSE cable gets warm as well but not unbearably, heat trace with back of your hand (carefully) can also trace which part gets hotter (receptacle or male cord cap) if you can't find you laser thermometer.
     
    Last edited: Aug 23, 2019
  9. BlueKonaEV

    BlueKonaEV Active Member

    The male cord cap gets the hottest as do the first 1.5 feet of the cable to the EVSE control unit. From the control unit to the plug that plugs into the car, it is only warm, not hot. If I would guess, I'd say that the cord cap is about 50 to 55 degrees Celsius
     
  10. electriceddy

    electriceddy Well-Known Member

    As above, suspect cord cap. Let me know how it goes . BTW those molded receptacles are not the best either , I would use a 4-11/16 box and a range receptacle c/w a 14-50 cord cap. (and maybe a 3/4 inch elbow to the panel) not 1/2
    Forgot to mention use a good crimper for attaching rings or hooks on the #8 conductors when securing them to the screws on the new cord cap
     
    Last edited: Aug 23, 2019
  11. BlueKonaEV

    BlueKonaEV Active Member

    Before I proceed with any major changes, I would like to know what temperature is normal. Maybe I will e-mail the manufacturer..
     
  12. electriceddy

    electriceddy Well-Known Member

    Ask them if they used crimps for the cap connections (they never seem to mention this pertinent info)
     
  13. KiwiME

    KiwiME Active Member

    It would be interesting to know if they did use the N blade as a ground, perhaps BlueKonaEV verify check continuity with a meter to the Type 1 plug?
    I haven't seen one of those outlets since I was a child living in upstate NY.

    Oh, just remembered there's a similar issue with a melting Nema socket on FB. Looks most like the wire clamp was loose at the socket.
    upload_2019-8-24_12-22-4.png
     
    Last edited: Aug 23, 2019
    electriceddy likes this.
  14. BlueKonaEV

    BlueKonaEV Active Member

    Will do. Hope that I'll be able to get any info from them.
     
  15. BlueKonaEV

    BlueKonaEV Active Member

    I don't think that mine is close to melting but it definitely hotter than I'd like it to be. I will keep looking for my laser temperature gauge to get more details on the temperature before contacting the manufacturer. It's not the outlet that is too hot.. it is the 10-30 plug. The outlet heats up but to a reasonable range that I would consider normal.
     
    Last edited: Aug 23, 2019
  16. BlueKonaEV

    BlueKonaEV Active Member

    Update: found my laser thermometer and plugged in the car. Temperature in garage is 33 C / 91 F right now at 9 PM. The plug is not hot yet.. Temperature slowly increases. Will check back in 1 hour..
     
    Last edited: Aug 23, 2019
  17. BlueKonaEV

    BlueKonaEV Active Member

    The numbers are in..
    Outlet: 45 C
    Plug: 55 - 56 C
    Cable where it exits plug 73 - 74 C
    Cable after 1st foot 45 C
    At J1772 plug, 40 C

     
  18. KiwiME

    KiwiME Active Member

    I'll defer to electriceddy's comments but I personally would replace both the plug and the socket at minimum. If the wiring to the panel is short, perhaps even change everything to a 4-wire type, or install a wall mounted, hard-wired EVSE.
     
    electriceddy likes this.
  19. electriceddy

    electriceddy Well-Known Member

    Yes . I didn't suggest that, eliminate the connection and hard wire with split bolts (insulated) would be best.;)
    The adjustable amperage portable type EVSE with a cord cap are great if travelling to an area such as campgrounds, but hardwired is better way to go for a permanent installation to avoid connection issues. The video positively confirms that the cord cap is creating the access heat. 73 degrees is too close.
     
    Last edited: Aug 23, 2019
  20. BlueKonaEV

    BlueKonaEV Active Member

    I e-mailed Mustart with my findings and asked them of this is normal or if the unit is defective.
    The outlet itself is not getting hot and it is brand new. If it is defective, I will try to exchange to a 32 amp EVSE for the 14-50 plug and replace the 10-30 outlet with a 14-50..
     

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