I'm installing an exterior junction box where I'm removing an old light fixture. I have a gasket to seal the cover to the box. But how do I seal the hole where the wire goes into the box?

  • What wire goes into the box? Did you remove a wire? Is there still power by another entrance? Need more details, but there are plugs for some types of outdoor boxes. – DaveM Jul 10 '16 at 2:39
  • There's a 2ft romex wire coming out of a hole in the wall. It used to extend to a light fixture in some nearby steps. I mounted the box next to the hole and routed the wire through a hole in the bottom of the box. – StepByStep Jul 10 '16 at 15:34

I decided to fill the hole with something called "duct seal" from my hardware store. It's like plumber's putty. I stuffed it in the hole and molded it around the wire. It seems to seal the hole up pretty well and is supposed to be weather-proof.

In retrospect, I probably should have bought a junction box that has a hole in the back and put it directly over where the wire comes out of the wall. I noticed that some have caps that can seal unneeded holes but not the model I bought.

  • Right; box with hole in back and, ideally a water proof clamp (may have to cut a bigger hole for that. I usually fill voids with silicone caulk. This putty sounds good. – DaveM Jul 11 '16 at 1:22

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