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NEMA 14-50 on a 60 amps breaker?

Discussion in 'Model S: Battery & Charging' started by xsi123, Nov 21, 2016.

  1. xsi123

    xsi123 Member

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    I am planning for charging for the new car. I will charge outside (no garage). I will install the HPWC, instead of NEMA 14-50, due to its long cable (24ft) and it will be exposed to rain and snow. I am also trying to plan for the future in case Tesla is not my preferred brand. So I would like the ability to replace the HPWC with just a plain NEMA 14-50 if I have to.

    --- I will use a 60 amps breaker. This will give me charging at 48 amps using the HPWC
    --- I will use a 6/3+ground cable (I need about 25ft). Even though the HPWC requires only 2 hot+ground cable, since I am planning for the future I will use a 3+ground cable to accommodate NEMA 14-50 in the future. I will just not use the 3rd cable for now.

    1) for the HPWC connection, should I connect the neutral cable on the neutral bar on the panel side and just cover it on the HPWC side? Or should I just cover it at both ends and don't connect it at all?

    2) is it ok to use a NEMA 14-50 outlet with a 60 amps breaker in the future? I can always just replace the 60 amps to 50 amps if I have to but just curious if it will work and if it is up to code.

    Thanks
     
  2. gregd

    gregd Active Member

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    I'm in the process of adding a 14-50 outlet in our garage, and for future upgrade opportunities have pulled #4 wire instead of #6. The run is about 40 feet. I asked the electrician if we should put in the higher current breaker, and he said no. Because the outlet is only rated at 50 A, the breaker should be the same.

    I would go ahead and connect the Neutral line at the panel while you're in there. Get it over with. This stuff is annoyingly stiff to work with, and easier to get done all at once instead of trying to go back and connect it later. It can be capped off and left unconnected at the HPWC..
     
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  3. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    1) You can connect it at the panel and cap it off with a wire nut at the HPWC end.

    2) No, it is not. You must replace the 60A breaker with a 50A if you pull it.
     
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  4. DarkMatter

    DarkMatter Member

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    Since this is a continuous load install you will need 4/3 if you are using NM-B cable to meet the minimum ampacity. If you're using THHN the #6 wire will be fine. You can't use the bigger breaker if you change out to a 14-50. Not allowed by code.
     
  5. bob_p

    bob_p Active Member

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    If everything works without problems, you should be able to use a 60A breaker, or any breaker that's at least 50A.

    HOWEVER, a 14-50 outlet is probably installed assuming that line won't handle more than 50A. And using a 50A breaker ensure that the circuit will never draw more than 50A. If you have any problems and the circuit has a 60A breaker, then you could run into problems if you run more current through a circuit designed for 50A.

    If you ever have the house inspected (which should happen if you sell the house), a 60A breaker on a 50A circuit is probably not "to code" and would have to be fixed before the house would pass inspection.

    And, if something bad did happen - and that circuit started a fire - and had an oversized breaker, you might not be covered by insurance.

    If in doubt, consult with a certified electrician in your area - who should be able to understand what is technically feasible - and what is acceptable.
     
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  6. DarkMatter

    DarkMatter Member

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    A 50 amp receptacle on a larger circuit violates 210.21(B)(1) of the 2011 NEC.
     
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  7. Boatguy

    Boatguy Member

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    Right. The breaker protects the weakest link in the circuit. In this case, the 14-50 outlet.

    So if, in the future, the OP replaces the HPWC with a 14-50, then he'll need to downsize the breaker to protect the outlet.

    OP: The breaker protects the wire and connectors from burning down your house. Always size the breaker to the weakest link in the circuit.
     
  8. ⚡️ELECTROMAN⚡️

    ⚡️ELECTROMAN⚡️ Fritterer and waster of hours in an off hand wayer

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    Are you talking about for the 60 Amp circuit? I'm pretty sure 6-3 NM-B would meet code for the 14-50 outlet.

    Definetly don't use a 60A breaker on a 14-50 outlet.
     
  9. TR5642

    TR5642 Member

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    Another thing to consider here is that if your panel has enough space and spare capacity, install BOTH the HPWC AND a NEMA 14-50 outlet. Then you are future proofed and friendly to EV visitors. The PROPER way is to run two separate circuits, on separate breakers. But I've seen some done with extending the circuit to an extra receptacle at point of charge. This is s no no because you can overload if you use both at once. Then there is the 50/60A issue others have mentioned. But, if I understand correctly, once you go to a 60A circuit, many local codes will require a separate interrupter/switch near the point of use/charge. At that point, perhaps it could be a switch for A-off-B (HPWC - off - NEMA). All ideas you might want to run by a pro before trying
     
  10. davewill

    davewill Member

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    A 14-50 isn't that useful for other brands since they don't come with portable 240v EVSEs. You will probably end up buying a J1772 EVSE at that time anyway, which would be hardwired. Of course, you could just buy one now and use it with your Tesla and be future proofed from the start. ;)
     
  11. DarkMatter

    DarkMatter Member

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    I'm talking about the 60 amp circuit, yes. 6/3 NM and direct burial cable will be rated for 55 amps. It will probably work but won't be to code.
     
  12. xsi123

    xsi123 Member

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    #12 xsi123, Nov 22, 2016
    Last edited: Nov 22, 2016
    A bit confussed here... and few more Qs (sorry)...

    1) So, what cable should I use if I just need to run it from the panel (inside the house) to the outside wall, (just behind where the HPWC will be installed)? The cable will not really be outside. Thru the wall it will just go in the HPWC using the rear entry (no top or bottom entry). Only the HPWC will be outside. Do I need an outdoors rated cable? To be on the safe side I will go with a 4/3. Is this ok?

    2) Do I need a 60 amps GFCI breaker since the HPWC will be installed outside? I think the HPWC is GFCI already so I probably don't need a GFCI breaker but not sure.

    3) What is the best way to seal the rear entry of the HPWC (where the cable will go in)? From inside the wall, I will use some spray foam sealant to close the hole but I am not sure what is the best way to seal the rear entry hole of the HPWC outside..
     
  13. Boatguy

    Boatguy Member

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    Yes, most EVs don't come with a portable EVSE which will plug into a 14-50.

    However, my JuiceBox EVSE (used for a BMW i3) plugs into a 14-50 and provides 9.6kW. I've tested it with my MS and it works fine.
     
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  14. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    If you seal things well, you don't need to use an outdoor cable. This is a bit of a gray area, but I see A/C wiring provided by NM cable punched through an exterior wall into a disconnect pretty frequently, and it passes. There are varying opinions on the technicalities associated with it.

    GFCI is not required for greater than 15A, 125V circuits. The EV code section requires ground fault protection be built into EVSE.

    I don't have any of the new ones handy, but typically you'd mount the HPWC bracket to the wall, then apply a bead of 40 year sealant completely around the top and sides, leaving a small hole in the bottom for drainage in case leakage does occur.
     
  15. DarkMatter

    DarkMatter Member

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    You aren't supposed to use THHN in the wall but it will be just fine. Lowes sells NM 4/3 by the foot online for about the same price so go ahead and use the correct stuff. Be forewarned that it's annoying to work with because it's so stiff.
     

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