My house was built in 1928 and I found one of my ceiling lights was "mounted" to this (it was actually screwed into the ceiling; hope they didn't nick a wire).

I'm trying to figure out what this is, mostly so I know how is it attached to the ceiling joist, how the electrical (possibly very old BX) may or may not be attached, etc. My goal is to put up a new fixture, though I'm currently thinking i won't touch the old wiring. Ceiling Fixture

  • @FreshCodemonger All the old wiring I've seen in this house is heavy armored cable (i.e. much heavier than the avg product I see in the stores) with cloth insulated wiring inside. Usually they're in an old box (black and smaller than current sizes). That said, I can't say this isn't K&T. Any idea what that black part with the hole for a screw is? It's hard to tell from the photo, but it extends out from the ceiling a little bit. Jan 23, 2023 at 1:29
  • Cloth-covered old wire is/was actually "insulated" with rubber. The cloth is just an exterior wear layer.
    – kreemoweet
    May 16, 2023 at 2:40

1 Answer 1


I finally figured this out, more or less. See two pictures below and my brief explanation.

First, I decided to trim away some of the plaster and verified the wiring is in an older box and is indeed BX.

The picture below is with that metal cap thing removed (the middle part with the screw has threads on the outside). I ended up taking out that screw and replaced it with a slightly longer screw so I could attach a crossbar.


This is what I removed; I'm not going to speculate how it was used, but I assume there was originally a hanging fixture.

Cap Thing

  • Please accept your answer to resolve this question.
    – isherwood
    May 16, 2023 at 18:08

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