My 1930's fireplace (Seattle WA, USA) has these inoperable sconces mounted on its face. The house has been updated to modern wiring, but these sconces were left alone and do not work. There is old fabric wrapped knob/tube wiring running from a central electrical box (pictured below) to the location of the sconces.

Two questions:

  1. What wire is acceptable to replace/pull through the old wiring? I would use normal 14/2 romex but given the install I am unsure it I would be able to pull a wire of that thickness/rigidity through the fireplace surround. Is there a smaller/thinner/more flexible type of wire that would be acceptable to use?
  2. These sconces do not have standard electrical boxes behind. Is it acceptable to run wire out of the wall directly into the existing sconces, presumable attaching the ground wire to the fixture body? Will I need to rework boxes here?
  3. If a 120V solution is not safe/allowed/prudent/workable/desired, can I run wire for a low voltage (12v/24v) LED solution without any concerns?

sconce sconce back sconce mount with location where wire enters wall central electrical box where sconce wiring runs to.

  • Do you know what U.L. Approved means?
    – Lee Sam
    Dec 12, 2020 at 22:39
  • You say that the fixtures don't have standard electrical boxes behind them, but you posted a picture of a standard electrical box (albeit not a box normally used for light fixtures...). Are there wall boxes or not? Dec 12, 2020 at 23:45
  • @JimmyFix-it Yes, apologies, that photo is of a central box where the wires from both sconces come together. I will edit for clarity.
    – John
    Dec 12, 2020 at 23:51
  • Is that wall box where the switch to turn them on is located?
    – FreeMan
    Dec 18, 2020 at 15:07

1 Answer 1


Your pictures don't show any wire coming out of the wall at the sconce and the wires in the central box look like they're cut short with no slack to pull out of the box to work. Knob & tube is normally attached to the knobs inside the wall and run as separate discrete wires so you cannot pull new Romex "through" the old wiring. Expect to run new wire from an accessible connection point all the way to the sconces, including installing new boxes and cover plates to attach the sconces to (yes, that means cutting holes, pulling wire, and plaster work).

I'm not sure what type of wire would be suitable to run through the fireplace surround due to heat from the fire. I would try to locate the first stud on either side of the fireplace, then run new Romex in that stud bay, installing boxes to relocate the sconces outside those studs, then patch the holes where they used to be. Relocating the sconces would apply whether you're running 120v or low voltage.

  • 1
    It's hard to tell where the lights are in relation to the fireplace itself (since it's not pictured), but, so long as the wiring isn't running too close to the flue itself, there shouldn't be a problem with heat. Otherwise, 100%!
    – FreeMan
    Dec 18, 2020 at 15:08

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