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  1. #1
    Join Date
    Apr 2010
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    Default Upgrading 2-prong to 3-prong in old 2-wire system

    I have a 1949 house, with 2-prong outlets and 2-wire system (no ground, even after opening the wrapping to check). All circuits are 20 amp, the panel is good. Also for safety I am checking for cracked rubber, and using shrink tube if any is exposed.

    Question: I want to upgrade some or all of my outlets to a 3-prong outlet. I installed 20 amp GFCI's where I needed these per the NEC(2-wire, no ground). If I install a 20 amp GFCI on the first outlet of a circuit, and supply the remaining outlets with the LOAD side... can I install regular 15 amp 3-prong outlets for the rest in the same circuit? And label them "No Equipment Ground" and "GFI Protected"?

    Thanks.

  2. #2
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    Apr 2010
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    Default Re: Upgrading 2-prong to 3-prong in old 2-wire system

    Thanks, I will make it happen.

  3. #3
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    Default Re: Upgrading 2-prong to 3-prong in old 2-wire system

    would'nt those outlets need to be 2 pronged outlets even gfi protected unless there was a egc connecting them to the gfi?
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  4. #4
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    Default Re: Upgrading 2-prong to 3-prong in old 2-wire system

    I don't have access to the NEC code ****** to check that out. But, the first non-grounded 2-wire outlet will be a GFCI. The remaining outlets don't need a ground wire since there would not be anything to ground the wire to.

    The GFCI will operate like this: It measures the volts/amps leaving the Hot side of the Load, and in return if the Neutral on the Load is -5v it will trip. The ground is not involved.

    I am no expert, but this is how I interpreted my findings. Please confirm for me.

  5. #5
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    Sep 2009
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    jersey
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    Default Re: Upgrading 2-prong to 3-prong in old 2-wire system

    I think theres room for improvement within the NEC here, simply reying on a sticker to tell someone there is no egc doesnt replace a ground. I understand that article thanks for clearing that up for me ernie, I'll once again fall back on the NEC NOT being a guide for electrical instalations but instead a MINIMUM stadard. Load protecting outlets without an egc isnt something I would practice, IMO I think your better served with devices that have no egc provision (2prong)
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  6. #6
    Join Date
    Jun 2007
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    Default Re: Upgrading 2-prong to 3-prong in old 2-wire system

    Quote Originally Posted by Lloyd View Post
    I think theres room for improvement within the NEC here, simply reying on a sticker to tell someone there is no egc doesnt replace a ground. I understand that article thanks for clearing that up for me ernie, I'll once again fall back on the NEC NOT being a guide for electrical instalations but instead a MINIMUM stadard. Load protecting outlets without an egc isnt something I would practice, IMO I think your better served with devices that have no egc provision (2prong)
    Lloyd, with a GFCI installed the ECG provides little if any protection other than what I described above..
    Jack
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  7. #7
    Join Date
    Jun 2007
    Location
    Shamokin, Pa.
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    645

    Default Re: Upgrading 2-prong to 3-prong in old 2-wire system

    Quote Originally Posted by Lloyd View Post
    I think theres room for improvement within the NEC here, simply reying on a sticker to tell someone there is no egc doesnt replace a ground. I understand that article thanks for clearing that up for me ernie, I'll once again fall back on the NEC NOT being a guide for electrical instalations but instead a MINIMUM stadard. Load protecting outlets without an egc isnt something I would practice, IMO I think your better served with devices that have no egc provision (2prong)
    Lloyd, I agree with your first sentence completely. {A small sticker in place of a ground wire?** But I believe the NEC just is covering all the bases on this one.

  8. #8
    Join Date
    Apr 2010
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    5

    Default Re: Upgrading 2-prong to 3-prong in old 2-wire system

    Quote Originally Posted by deadshort View Post
    Read through my 08 NEC Quote in post #8 and consider yourself confirmed.
    Thank you. To me, this is confirmation for what I would call "the best solution to meet code, to get 3-prongs everywhere, and not have to run new wire everywhere". I've been finding out that a GFCI protected outlet with no ground is safer for the elec device plugged in, and for personal safety; in comparison to a grounded non GFCI.

    Yes, some devices notice there is no ground (like an APC battery backup device) and they warn you of this but knowing it's protected by gfci is safe if not safer.

    I consider this one closed. That you for the copy/paste from the NEC.

  9. #9
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    Sep 2009
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    jersey
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    174

    Default Re: Upgrading 2-prong to 3-prong in old 2-wire system

    Sorry I cant get on everyday and our conversations tend to get drug out but..

    I understand How a gfi works.
    I understand how potential differences create hazzards

    but thanks for explaining that to me.

    There are a few key points here I want to restate.

    1) there is no EGC between the device (three prong) and the gfi so the GFI would NOT detect a fault current on the EGC if it existed on an appliance plugged into the three prong outlet.
    2) I keep hearing that the EGC provides little additional protection.. I disagree .. it enables an appliance to become effectively bonded to other metal non current carrying parts of the electrical system that may become energized.

    My point

    IMO the NEC has some short comings here. Replaceing a 2 prong with a gfi is great if you cant get a ground to it, but load protecting other devices isnt a great practice IMO. I think your better served pulling a piece of thhn for an egc.
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  10. #10
    Join Date
    May 2010
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    Default Re: Upgrading 2-prong to 3-prong in old 2-wire system

    I believe the NEC just is covering all the bases on this one.




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