Attempting to replace a bathroom vanity light fixture, removed the previous fixture and found a rough hole in the drywall with metal clad cable containing only 2 wires (yellow and white) - no ground wire observed and no junction box.

I have been trying to look up the proper way to install the new fixture safely, and am currently under the impression I should install a metal (old work) junction box (as the cable is metal clad) using a connector along with an anti-short bushing and then install the new fixture.

Is this a correct plan and what should I do about the lack of a ground wire?

enter image description here

  • 4
    Based on (a) colors yellow/white instead of standard black/white and (b) amount of space around the wires, that looks like flexible metal conduit rather than armored cable. Which also means, but I'm not 100% sure so just a comment and not an answer, that the metal is a valid ground within certain constraints. I'd check continuity metal to white neutral - if it shows good (close to 0 ohm) then with a properly attached metal box I think you're all set. Jan 16, 2022 at 5:45
  • 1
    This might be helpful: homedepot.com/p/… you screw that into the cable, then the entire metal box becomes the ground. (There are different sizes, I picked a random one.)
    – Ariel
    Jan 16, 2022 at 18:30

1 Answer 1


Task completed.

  1. Tested flexible Metal Conduit for grounding, and it was grounded. (written method and video tutorial here)
  2. Used a "3/8 in. Flexible Metal Conduit (FMC) Screw-In Connector" to secure conduit to a "RACO 1-Gang Gray Metal New Work/Old Work Standard Octagonal Ceiling/Wall Electrical Box ", then secured box to a stud. Because the connector separates the wires from the edges of the conduit in its basic construction, I did not use a plastic bushing in this case.
  3. Checked the box grounding with multimeter and confirmed.
  4. Finished with typical ground-to-box, white-to-white, and black(yellow)-to-black connections using appropriately sized wire nuts.
  • Well done! Note that if you connect "hot-to-hot" and "neutral-to-neutral", you get around the pesky black/yellow problem. When run in conduit, white & grey are neutral, green (if present) is ground, and all other colors are hot.
    – FreeMan
    Jan 20, 2022 at 13:54

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.