I've recently removed the light fixture in my kitchen / breakfast area in a condo (ceiling is NOT drywall, as far as I can tell). I got a new fixture that I want to install but it weighs around 6 kilograms. While trying to install it, I noticed that the plastic part around the screw mounts in the junction box is broken. So this box basically has 4 screw mounts (positioned like a plus sign +). But the ones used for the old fixture were they only 2 exposed and had a crack each. You can see in the pictures. It was firm but the look of a cracked plastic piece freaked me out so I decided to use the other 2 screws mounts (previously covered by plaster or drywall but I was able to scratch and dig my way to them. they're weird because the same screw keeps slipping from them. Im not sure if they have a different size.

  1. What is the size of the other 2 screw mounts? (That is if it is standard).
  2. If nothing worked, can I replace the junction box or is it a hastle since it's in a condoo??
  3. Is drilling new holes in the ceiling next to the existing big hole a good idea?

cracks on plastic part


  • You are 100% correct that relying on those cracked mounts isn't a good idea for a 6Kg light fixture hanging above your head. Please take a wider angle picture to give us an overall view of the ceiling box. Also, the yellow wire insulation indicates that you've either got conduit or you're not in the US. Please indicate your locale.
    – FreeMan
    Mar 21, 2022 at 12:09

1 Answer 1


The crack shown is not too concerning - the screw is held by the brass insert, and the brass insert does not appear to be in any danger of coming loose based on your picture, and the fact that it held the previous light fixture, presumably for many years.

  • Thanks! So what is the brass insert holding on to? Just the plastic bit? Would using a silicone adhesive make the plastic stronger? I need some reassurance to know it is strong enough otherwise I'll cringe and worry everytime I pass under the fixture lol Mar 21, 2022 at 1:52
  • It appears to be held by the shape of the plastic bit, which appears to be solidly connected to the rest of the box, and the apparent shape of the metal insert. The position of the crack is about tthe least structurally concerning location it could be. Each half of the plastic seems to be fully connected to the box.
    – Ecnerwal
    Mar 21, 2022 at 2:00

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