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  1. #1
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    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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    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
    Join Date
    Jun 2007
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    Shamokin, Pa.
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    Default Re: Upgrading 2-prong to 3-prong in old 2-wire system

    Quote Originally Posted by deadshort View Post
    Go read through 406.3(D)(3)
    I agree, depending on the marking provided, they could be either a two prong non ground outlet section {3**{b** or a three prong grounded type in section {3**{c**. All in 406.4{D**{3**, of course.

  6. #6
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    Shamokin, Pa.
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    Default Re: Upgrading 2-prong to 3-prong in old 2-wire system

    As I read it the key is getting all your ducks in a row, ie, the proper placement of the GFCI......

  7. #7
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    Default Re: Upgrading 2-prong to 3-prong in old 2-wire system

    Quote Originally Posted by deadshort View Post
    406.3 Ernie, 406.3...........

    "(3) Non–Grounding-Type Receptacles. Where attachment
    to an equipment grounding conductor does not exist
    in the receptacle enclosure, the installation shall comply
    with (D)(3)(a), (D)(3)(b), or (D)(3)(c).
    (a) A non–grounding-type receptacle(s) shall be permitted
    to be replaced with another non–grounding-type receptacle(
    s).
    (b) A non–grounding-type receptacle(s) shall be permitted
    to be replaced with a ground-fault circuit interrupter type
    of receptacle(s). These receptacles shall be marked
    “No Equipment Ground.” An equipment grounding conductor
    shall not be connected from the ground-fault circuit interrupter-
    type receptacle to any outlet supplied from the
    ground-fault circuit-interrupter receptacle.
    (c) A non–grounding-type receptacle(s) shall be permitted
    to be replaced with a grounding-type receptacle(s)
    where supplied through a ground-fault circuit interrupter.
    Grounding-type receptacles supplied through the ground fault
    circuit interrupter shall be marked “GFCI Protected”
    and “No Equipment Ground.” An equipment grounding
    conductor shall not be connected between the grounding type
    receptacles."
    While this does meet NEC and safety requirements it should be noted that it may not meet grounding requirements for some electronic equipment that have filtering to ground.
    Jack
    Be sure you live your life, because you are a long time dead.-Scottish Proverb

  8. #8
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    Default Re: Upgrading 2-prong to 3-prong in old 2-wire system

    Quote Originally Posted by JLMCDANIEL View Post
    While this does meet NEC and safety requirements it should be noted that it may not meet grounding requirements for some electronic equipment that have filtering to ground.
    Jack
    True. But in the real world what would those issues be?
    I am not getting into a flame war here, just posting that question...

  9. #9
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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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  10. #10
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    Default Re: Upgrading 2-prong to 3-prong in old 2-wire system

    Quote Originally Posted by Ernie_Fergler View Post
    True. But in the real world what would those issues be?
    I am not getting into a flame war here, just posting that question...
    In some electronic system filters to ground are used to remove electrical noise both internally created and from external sources. For instance, the shield on a coax cable must be grounded to prevent piggybacking extraneous RF signals.
    Jack
    Be sure you live your life, because you are a long time dead.-Scottish Proverb

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