I'm planning to re-wire a ceiling light fixture in order to bring a neutral line down to the switch box. I've identified where all of the lines go in the attic, it's easily accessible and there's no insulation in the wall (it's an interior wall) so this should be an easy project.

However, I opened up the light fixture to check it out and see if anything funny is going on... and I found this:

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So far, it looks fairly normal, the neutral and hot wires come together in wire nuts to connect to the fixture. However when I pulled it down a bit further, I found some really weird crap up there surrounding the wires:

enter image description here

What is that stuff? It's taking up space in the box and it's not electrical wires, that doesn't seem like it's safe... Can I pull it out? It's almost like it's a kind of insulation, except it's solid.

For reference, here's what things look like in the attic:


  • Plaster base coat basically mortar
    – Kris
    Commented Jul 23, 2020 at 21:14
  • @Kris and why would it be inside an electrical box??
    – Jason
    Commented Jul 23, 2020 at 21:15
  • 1
    Looks like an insect nest to me. Bee nest? Commented Jul 23, 2020 at 21:17
  • It might be a nest... we don't have any bug problems though. It could be an old one, the house was built in the 50s.
    – Jason
    Commented Jul 23, 2020 at 21:18
  • 3
    Mud wasp dirt dauber
    – Kris
    Commented Jul 23, 2020 at 21:20

2 Answers 2


Standard "mud dauber" wasp nests ( in TX). Theold mineral wool thermal insulation has collapsed , pretty typical. It would be well worth getting a price of blowing in fiberglas or putting batts of fiberglas yourself.

  • It’s above my utility room which isn’t conditioned space, so that’s why it doesn’t have enough insulation. I may add some of that soon once I’m done with this project. With regards to the wasp nest do I need to be concerned about live wasps?
    – Jason
    Commented Jul 23, 2020 at 23:33
  • 1
    Looks like a dead wasp in the front one. As far as being concerned about live ones, if you are not seeing them in the house, you are probably safe. But when they sting you, you will know it. Commented Jul 24, 2020 at 0:30

It looks like a bee cocoon. Shut off the power, spray with some bug spray just in case any are alive and scrap it out with a screwdriver.

  • Should I be concerned that there are bugs alive in there? We haven't seen any bugs in the room or in the attic.
    – Jason
    Commented Jul 23, 2020 at 21:24
  • @Jason One step at a time, clean out the box. You'll get a good idea if it's old or new. Are the wires in conduit? You were in the attic, right? Did you see anything ?
    – JACK
    Commented Jul 23, 2020 at 21:30
  • wires are not in conduit, they are exposed in the attic like this, i.sstatic.net/xMK3X.jpg - as you'll see they are easily accessible and I don't see any bug nests or anything in the attic. G stands for ground.
    – Jason
    Commented Jul 23, 2020 at 21:32

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