I took off a bathroom fixture hoping to replace it, thinking it would be a simple job. Well it turns out there's no junction box. I could just wire things up and it'll work, but that doesn't seem right.

Upon closer inspection, I realized why they installed it this way. The fixture is centered to the vanity, and there is a stud. But right alongside it is a black PVC pipe, which I imagine is some kind of a venting pipe (this is a top floor bathroom). This is the opened up cavity below my vanity, so I'm assuming the top would be the same.

enter image description here

So the right screw here goes into wood, and the left one goes into a drywall with an anchor.

enter image description here

Looking at other answers on here, most people suggest a pancake junction box like this one, which I understand can be mounted to a stud directly and will be flush with drywall.

My problem is, how do I run the Romex cable through the back of a pan box, if there is a PVC pipe in the way?

  • 1
    Just to confirm you are in US/Canada for code. Any play/slack in the cable(can you pull it from the wall)?
    – crip659
    Jul 28, 2023 at 1:23
  • 1
    @crip659 I am in Canada & yep there is a significant amount of cable inside the wall (can be pulled out)
    – Deal
    Jul 28, 2023 at 2:04
  • That's not necessarily why they installed it that way. When I was actively building (1990s through mid-oughts), electricians often merely poked cable through the drywall and made the connections in the enclosed bar-type fixture box, which is (at least was) perfectly legal if done properly. The benefit was that they could leave cable coiled in the wall to allow for variation in fixture position once decisions were made regarding mirrors, towel bars, etc.
    – isherwood
    Jul 28, 2023 at 16:02
  • Maybe you're right! It was a bar style fixture as you could probably tell from the outline on the drywall
    – Deal
    Jul 29, 2023 at 21:18

1 Answer 1


The vent pipe is smaller in diameter than the thickness of the stud.

You should be able to mount the pancake box with a knockout toward the vent pipe side. Then have enough room to sneak the cable in the box. Don't forget to use a strain relief/ insulator .

  • Thank you. I had enough room to slide the cable between the pipe and drywall. There was no room to fit a strain relief though. They don't seem to sell slim ones like the one you linked, in Canada.
    – Deal
    Jul 29, 2023 at 21:20

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.