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grounding with 2 wires

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  • grounding with 2 wires

    Is there a safe way to install a fixture with a ground wire to an older 2 wire system? I assume you should probably rewire, but any insight will be appreciated.


  • #2
    How old a two wire system are you talking about? Hopefully not knob and tube. If its two wire with an armored covering(i.e., BX), it is probably grounded. To verify, open up the electrical panel and look for a lead that connects the grounding bar to either your domestic water main or to one or more outdoor grounding rods. Should your system be grounded armored cable, fixtures, plugs and switches should be connected to the box in which the connection is made via uninsulated copper wire of the proper size which connects the ground (screw) on the plug, switch or appliance to a grounding screw in the box. The idea here is to provide a path for "errant" current from a line source to ground. You never want to be in a position where you make the ground.

    If your system is knob and tube, I'll leave it to the pros to reply regarding grounding.
    there's a solution to every just have to be willing to find it.


    • #3
      Sometimes if there is not a ground we don't bother with it but if you want to have it bonded then you can always run 14 or 12awg to each light and then back to your panel's ground bar. If you have conduit like my in-laws house you are in luck. All you have to do is use the green screw on the mounting bracket that came with your light, and that will bond it to the conduit as well. If neither of those is feasible then just make sure that the hot and neutral are not going to be damaged while the light is put in and you'll be fine. Outlets are more important to have grounded, IMHO.
      "Diplomacy is saying nice dodging until you can find a rock." Will Rogers
      "If a Monkey can do your job, are you in the right profession?


      • #4
        yes i have to agree with polar sparky for your lighting i would not be too concerned but i will say sometimes when installing flourescent lights they tend to not work well without a proper ground