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NEMA 6-50 vs 14-50

Discussion in 'North America' started by ZestyChicken, Feb 21, 2014.

  1. ZestyChicken

    ZestyChicken Member

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    #1 ZestyChicken, Feb 21, 2014
    Last edited: Feb 21, 2014
    My mother-in-law installed a Clipper Creek charger for her Volt. The electrician installed a plug for me so I could charge my Tesla via the mobile charger rather than via the J1772. Unfortunately,
    - the guy installed a 10-50 plug which has no adapter (kind of a dead standard)
    - He ran a 3 cable wire without a ground (hot-hot-neutral)

    Anyway, I am going to replace the plug and re-wire it. My question is can I just swap out the plug and wire the ground to the receptacle? The Clipper Creek device will also need to be grounded to that...

    Any opinions/thoughts from the electrical engineers in the crowd (no idea why these pics are sideways)?

    IMG_3295.jpeg IMG_9820.jpeg
    IMG_7266.jpeg IMG_9767.jpeg

    http://www.qualtekusa.com/PDFs/nema_nonlocking_configuration_chart.pdf
     
  2. dhrivnak

    dhrivnak Active Member

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    To fully meet code you should have a separate ground. But the reality is that neutral is tied to ground. The Tesla (Roadster) and the Clipper Creek have only 3 wires to attach so the neutral is not used. So you should be able to use the neutral as ground and wire the two hots.
     
  3. qwk

    qwk Model S P2681

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    I would just build an adapter. The 10-50 outlet is the second most common outlet in the wild, right after a 14-50.
     
  4. ZestyChicken

    ZestyChicken Member

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  5. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    The 6-50 is acceptable with modern wiring practices, the 10-50 is not. From NEMA connector - Wikipedia, the free encyclopedia:
    If done correctly, the three wires in the 10-50 are white for neutral, and black/red for the two line/hot connections. It is acceptable in wiring to repurpose a wire to a different color coding by wrapping both ends with the correctly colored electrical tape. If I were you, I would (or have my electrician) replace the 10-50 with a 6-50, and re-label the white neutral used for the 10-50 with green electrical tape on both ends. Then you can connect the 6-50 correctly with a green ground wire and the hots/lines with the red and black wires. Then just order a 6-50 for your UMC.

    References:
     
  6. FlasherZ

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

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    #6 FlasherZ, Feb 21, 2014
    Last edited: Feb 21, 2014
    No, no, no!

    Neutral and ground are two distinct, separate things. Yes, they are connected together in one place (at the service panel), but from there they are different and distinct, and sometimes use different wire sizes!

    So here come a few technicalities for you:

    First of all, in the US, post adoption of NEC 1996, installation of any NEMA 10 series receptacles is forbidden by code for new construction. NEMA 10 series receptacles are only legal as direct replacements in existing installations. So I have no idea why your electrician did this in the first place, and it's not to code. You should call him back and have him install the correct outlet for you.

    Technically, it will work if you replace the 10-50 with a 6-50, and use the neutral conductor as ground. HOWEVER, at the source panel, if it is not the service panel, the neutral conductor will need to be moved to the ground bus. Only in the service panel are the two bonded together.

    However, per code, this will be disallowed as ground conductors must be green or green with yellow stripe only. (See below for my post where you may remark conductors of a multi-conductor cable.)
     
  7. miimura

    miimura Active Member

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    @ZestyChicken

    Did you remove the cover to see what the wire colors are?
     
  8. FlasherZ

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

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    Not in all cases. Only when the wires are part of a multi-conductor assembly (NM-B "Romex" cable assembly, or "armored" cable) or the wire is larger than 6 AWG (not including #6) is this legal; if the run consists of separate wires of #6 or smaller in conduit, the conductors must be green or green with yellow stripe. See NEC 250.119, exception 250.119(B).
     
  9. ZestyChicken

    ZestyChicken Member

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    Well she lives about 250 miles away so I won't be able to check until March. However, I went ahead and ordered the adapter so I should be set.
     
  10. hcsharp

    hcsharp Active Member

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    As soon as I saw your picture of a 10-50 outlet, my immediate reaction was "It's been illegal to install one of those for a long time." I can't believe an electrician actually did that. I would make him come back and install a 6-50 or 14-50 and make sure he doesn't charge you for it. If he refuses, just threaten to call an inspector and his license will be on the line. Am I missing something here?
     
  11. qwk

    qwk Model S P2681

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    I thought the same thing, but see new 10-50 installations all of the time.
     
  12. FlasherZ

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

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    If you have an inspector. In my county, for example, no permits are required (except general building permits) and no inspections required although we've formally adopted the NEC. The county to the east of mine doesn't even have building permits. Electricians can install 10-50's at will and not risk anything. Technically, almost every state has adopted the NEC and has some laws regarding it, but it's not likely to be pursued very eagerly.
     
  13. hcsharp

    hcsharp Active Member

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    We don't have inspections or require electric permits (except public buildings) but we do have a licensing board for electricians. The guy will probably fix it if you ask. While I generally don't recommend sticking the "Man" on somebody, I would threaten to call the licensing board if he didn't fix it for free. Even it they won't pursue it, he doesn't want his livelihood threatened. Fixing mistakes is built into his rate. You certainly didn't ask for a deprecated outlet that's illegal to install.
     
  14. Chris TX

    Chris TX Active Member

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    Do you know if 6-2 or 6-3 was used? There might be a ground wire already run, but not hooked up to that outlet.
     
  15. FlasherZ

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

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    6/2 or 6/3 are designations for pre-assembled cables, like NM-B and don't apply in the case of wire-in-conduits.

    It's unclear the specific type of conduit that is used. The fitting attached to the box appears to be a liquid-tight fitting, but I can't tell if the conduit is LFNC-C (nonmetallic, which would require a grounding conductor to connect to that metallic box), or if it's some type of coated LFMC, which can be used as a ground for up to 60A.

    It's most likely LFMC-C and you have a ground wire running through there, in which case you'd simply cap off the white and use the red, black, and green to connect a 6-50.
     
  16. ZestyChicken

    ZestyChicken Member

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    Are you sure it's illegal to install? They still sell the receptacles:

    Receptacle, 50 A, Nema 10-50 - Amazon.com
     
  17. FlasherZ

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

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    #17 FlasherZ, Feb 25, 2014
    Last edited: Feb 25, 2014
    Yes.

    NEC 1996 and later forbid the way appliances are connected via a 10-50.

    The reason they're still sold is that it is permitted to replace defective receptacles with a new NEMA 10-50 receptacle. You simply may not add a new one on a new branch circuit or extend an existing branch circuit.

    More detail for those interested. Code reference NEC 2011 sec 250.140 required the frames of ranges and clothes dryers to be connected to an equipment grounding (ground) conductor for new branch circuits, this was introduced in 1996. Code reference NEC 2011 sec 250.142(B) specifies that a grounded circuit conductor (neutral) shall not be used for grounding non-current-carrying metal parts of equipment.

    So *technically*, it's not the NEMA 10-50 that is outlawed, but rather grounding any appliance via the neutral pin. Since NEMA 10 has no provision to extend ground to the appliance and since grounding is required, it can't meet the needs of any appliances and therefore should not be installed for new branch circuits.
     
  18. markb1

    markb1 Active Member

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    Are we sure the electrician was even licensed? I would hope that a licensed electrician would know better than to install an ungrounded outlet. (Though I guess I shouldn't be surprised.)
     
  19. ZestyChicken

    ZestyChicken Member

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    #19 ZestyChicken, Feb 25, 2014
    Last edited: Feb 25, 2014
    1Hmmm...this is all very interesting. Here's the install manual from the Clipper Creek device:

    Screen Shot 2014-02-25 at 6.38.54 PM.png

    This shows three wires. According to my mother-in-law, he installed a 3 wire cable without a ground. That will work for the NEMA 10-50 (hot-hot-neutral). I'm guessing he is just grounding the Clipper Creek device to the receptacle box?

    Again, I'm clearly the least educated of your guys w/r to this stuff, but these diagrams seem to suggest the only difference between 10-50 and 14-50 is the ground protection.

    Screen Shot 2014-02-25 at 6.46.34 PM.png
    Screen Shot 2014-02-25 at 6.46.46 PM.png
    Screen Shot 2014-02-25 at 6.47.03 PM.png
     
  20. voidptr

    voidptr Member

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    The clipper creek is three wires with Hot/Hot/Ground, no neutral. There's 240V between the two hots, and 120V from each of those to ground, but under normal operation there's no current on the ground wire. A 10-X device is Hot/Hot/Neutral-Ground, a 6-X device is Hot/Hot/Ground. Electrically the third wire is mostly the same, but the former the device is allowed to draw unbalanced current from the hot legs and return the imbalance through the third wire, the latter must draw and return through the hot legs only, the ground is only for safety.

    You can swap out the 10-50 for a 6-50 by changing third wire to ground, but there are code implications in the marking of the wire and which bus it is on if there's a subpanel in the mix.
     

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