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  1. #1

    Default Grounding and BX Cables.

    My house is from 1920. All the wiring is BX Cables just balck & white, no green / ground cable. The box is grounded to the water waste pipe in the basement.
    As I am installing new lights fixtures & outlets (with a ground cable), how am I supposed to ground them and keep it all safe.

    Hereis what I read here:

    " BX Armored cable: A flexible steel sheath covers hot and neutral wires, which are insulated with cloth-covered rubber. The sheath provides a ground, so grounded receptacles are easy to retrofit."

    Should I then attached the ground cables fron the new fixtures to the box which connected to the cable will ground it?

    Thanks.

  2. #2
    Join Date
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    Default Re: Grounding and BX Cables.

    Here is a link to a previous discussion ... in particular post number 7 :

    http://advice.thisoldhouse.com/showthread.php?t=1704

  3. #3
    Join Date
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    Default Re: Grounding and BX Cables.

    A simple answer to your question is, Yes, if the BX jacket is in good shape, the mechanical connections to the BX are in good shape, the box is metal, and the BX is properly grounded.
    Jack
    Be sure you live your life, because you are a long time dead.-Scottish Proverb

  4. #4
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    Default Re: Grounding and BX Cables.

    Couple things:

    Your old BX cable sheath was never designed to be used as a ground conductor and neither was the fittings used for it.

    Modern day AC and MC cable either has an aluminum trace wire running the length inside the cable, uses a full sized insulated copper conductor or some really new stuff that uses a full size bare aluminum conductor which is not terminated in the junction boxes and requires a special connector.

    If you theoretically could use the sheath for a “ground” then the neutral bar in your panel would need to be bonded electrically to the panel its self. Because if there is a short circuit between the hot and ground you want the ground conductor to be an alternate path back to the neutral.

    The idea that if a hot shorts to ground it some how dissipates into the earth is an erroneous idea.

    Also, your panel is grounded to a “waste” pipe? That is not a recognized grounding means. 10’ of copper waterline in contact with the earth would be recognized and so would a ground rod.

  5. #5

    Default Re: Grounding and BX Cables.

    OK, so except rewiering the house completely, should I just not ground these? The GFCI type receptacles sounds like a good idea, but how about light fixtures? should these not be grounded somehow and how?

    As for the grounding of the box, it is attached to the main water supply pipe.

    Thanks.

  6. #6
    Join Date
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    Default Re: Grounding and BX Cables.

    Well, I’m not going to come out in a public forum and suggest you do something that does not meet NEC code requirements.

    What would I do in the same situation? Now there is a thought to ponder...................................

    One thing I would do is make sure your neutral is bonded to the panel at your service entrance if you go the route you’ve suggested. Or, your attempts to “ground” will be doing nothing.

  7. #7
    Join Date
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    5,557

    Default Re: Grounding and BX Cables.

    The NEC now requires a grounding rod but I can remember when grounding to the waterline was quite common.
    Jack
    Be sure you live your life, because you are a long time dead.-Scottish Proverb

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