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Model 3 Charger not turning on with 50 amp plug

Discussion in 'Model 3: Battery & Charging' started by Starvin, Jun 21, 2018.

  1. Starvin

    Starvin Member

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    I had my electrician install a nema 14-50 plug to use with the included adapter that came with the model 3. He used a 50 amp breaker and 6/3 wire. After the install, he used a voltage meter on the plug and both sides were reading 120V, so 240V total. It clearly has enough power. However, when I plug in the charger, nothing happens. No lights come on at all. At first I thought it was a problem with the charger, so I tried plugging it into the 14-50 plug in my kitchen that the stove uses. It powered on just fine. The kitchen plug uses a 40 amp breaker.

    I called Tesla and they don't know what the problem is. What could be going wrong?
     
  2. tes-s

    tes-s Member

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    It could be wired wrong. Both sides reading 120v does not necessarily mean there is 240v - would be 0v is both were the same phase.

    Not sure how an electrician could install it wrong, but you never know. Size of wire / breaker would not affect your EVSE powering on.
     
    • Helpful x 1
  3. andrewket

    andrewket Well-Known Member

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    Your kitchen should not have a 14-50 using a 40a breaker. But we’ll leave that alone.

    Tes-s’s guess is a good one. Both legs are on the same phase. How any electrician could screw that up is beyond me, but it fits.

    Are you sure the breaker is still on? Do you have a multimeter that you can use to check the voltage across both legs?
     
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  4. iwannam3

    iwannam3 Member

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    Each side of the breaker panel each connection alternate phases. Counting from the top for example, Odd # breaker spots are L1 and even are L2. Your wires should come from adjacent connections in the panel so you have L1 and L2. L1 to ground is 12oV to ground, L2 is 120V to ground and L1 to L2 is 240
     
    • Informative x 1
  5. eprosenx

    eprosenx Active Member

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    If you are comfortable with electricity and have a multimeter I would check the following:
    From each "hot" to neutral should read roughly 120v. From each "hot" to ground should be roughly 120v. From hot to hot should be roughly 240v.

    As others have mentioned, if both sides were hooked to the same "leg" of the panel there would be no "potential" between them, but that would be pretty hard to screw up since the breakers themselves are dual pole and physically only fit in the panel across two phase legs.

    Interesting that your UMC comes on when plugged into the kitchen plug. That makes it seem like it is not an issue with the UMC.

    Note that the UMC does test for you having a solid ground connection so if the electrician failed to connect up the ground properly that could explain why you have good voltage hot to neutral but yet the UMC does not work. (btw, the UMC totally ignores the neutral, so it could be totally disconnected and the UMC would not care)

    Actually, this is a common misconception but it is completely legit to have a NEMA 14-50 on a 40 amp circuit as long as the range/oven plugged into it does not violate the 40 amp ampacity rating of the circuit (after applying the allowed demand factor which actually reduces your circuit ampacity requirements). I am looking at 2017 NFPA 70 / NEC Article 210.21 - Outlet devices.

    My reading of the NEC actually would allow you to use a 40 amp circuit on a NEMA 14-50 receptacle for your UMC since the UMC Gen 2 only has a nameplate rating of 32 amps, so a 40 amp circuit actually meets the 1.25 continuous load multiplier requirement.

    Btw, have you tried the UMC with the plain old NEMA 5-15 adapter that comes with it as well just as another data point? (if it works on your Range plug though that is probably the best test of the UMC since it even uses the same adapter)
     
    • Informative x 2
  6. ewoodrick

    ewoodrick Active Member

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    Did he use 6/3 or 6/3 with ground?
     
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  7. Rocky_H

    Rocky_H Active Member

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    That is actually specifically allowed by code.
     
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  8. Starvin

    Starvin Member

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    Thank you everyone!

    It turns out that both legs were on the same phase. iwannam3 explained it well for someone like me who knows hardly anything about electricity. I moved the breaker up a single spot so it was using both phases and now everything is working flawlessly.
     
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  9. davewill

    davewill Member

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    Was this a licensed electrician or some handyman? Let me guess, he told you you didn't need a permit? :rolleyes:

    Pretty bad mistake. Would make me wonder what else is wrong.
     
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  10. eprosenx

    eprosenx Active Member

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    So what type of panel do you have? Most panels every other position is alternating phase. I am concerned you may have a federal pacific or stab-lok style panel. Those are the only ones I have seen that are offset as you describe (there could be others though).

    If you do have a federal pacific stab lok panel be aware they are considered serious safety hazards at this point. They just did not work well and have failed to operate properly to the point that they are recommended to be replaced.
     
  11. iwannam3

    iwannam3 Member

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    Wow, any 2 adjacent slots should be L1 and L2. To get two L1s normally you would need to have 2 separate breakers with another single breaker in the middle. eprosenx must be right, an old weird breaker box that tricked your electrician. I am assuming they used a paired breaker with the switch levers connected so both have to be on or off?
     
  12. eprosenx

    eprosenx Active Member

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    Can you post a picture of the panel and of the sticker on the door that has all the gory technical details? I am curious now.
     
  13. Starvin

    Starvin Member

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    Yes it is a stab lok style panel, but it is the Canadian version which is federal pioneer and not federal pacific. I did a bit of research and apparently they did not have the same problems as the US version. Most breakers in there (including the new 50 amp one) are also now schneider brand which bough out fpe.

    r/electricians - Federal Pioneer Stab-lok Panel

    My panel is a 200 amp "be 120-40".
     
  14. Starvin

    Starvin Member

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    Yes, it is a paired breaker with the switch levers connected. I guess he has never seen a breaker box like this before.
     
  15. tes-s

    tes-s Member

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    Is your electrician you? :)
     
    • Funny x 1
  16. Starvin

    Starvin Member

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    Might as well be me at this point. But no, I only routed the cable through the house and then got him to hook everything up to the plug and breaker box.
     

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