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    Tom Hartsell's Avatar
    Tom Hartsell Posts: 2, Reputation: 1
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    #1

    Dec 20, 2007, 09:43 AM
    Can you use Metal Conduit as ground to convert 2 wire to 3 wire?
    I need to convert an old cinder block house from 2 wire outlets to 3 wire by adding a ground to all outlets.

    Since the entire house is cinder block, all the circuits from the basement breaker box are in flexible metal conduit and metal outlet boxes...

    Is it possible to use the metal conduit as the ground without running a ground wire to every
    Outlet in the house?

    I also need to add an isolated ground in the breaker box? Right now all grounds are
    On the white side of the circuit and there is no isolated ground on the breaker box.

    Thanks in advance for advice.
    tkrussell's Avatar
    tkrussell Posts: 9,659, Reputation: 725
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    #2

    Dec 20, 2007, 09:57 AM
    Flexible metal conduit may be used as an equipment ground conductor, but only if several conditions are met.

    At this stage, it will be impractical to meet these conditions, so all I can advice you is to not use the FMC as an EGC, and pull an additional green wire through the system.


    A separate equipment ground bar is not needed if the panel contains the Main breaker. Let me know what you have.
    Tom Hartsell's Avatar
    Tom Hartsell Posts: 2, Reputation: 1
    New Member
    		  
    #3

    Dec 20, 2007, 11:59 AM
    Quote Originally Posted by tkrussell
    Flexible metal conduit may be used as an equipment ground conductor, but only if several conditions are met.

    At this stage, it will be impractical to meet these conditions, so all I can advice you is to not use the FMC as an EGC, and pull an additional green wire thru the system.


    A separate equipment ground bar is not needed if the panel contains the Main breaker. Let me know what you have.
    Looks like the original fuses were replaced at some point with Square D QS? Or QO? Breaker Box.

    I don't see an isolated ground bar on the inside of the box however. The screws that typically
    Connect the white side to the Box are NOT installed so I assume there is an isolated ground if I actually drove a stake in the ground from outside. Looks like there is one ground wire
    Attached directly to the white side... comes from outside maybe the new air conditioner... have not investigated.
    tkrussell's Avatar
    tkrussell Posts: 9,659, Reputation: 725
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    #4

    Dec 20, 2007, 12:22 PM
    Where is the Main Breaker?
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