Electrical – How to install a junction box with NM-clamps

electricaljunction-boxwiring

I bought a junction box in order to splice three Romex together along the 2×4's in the ceiling of my (unfinished) basement. The box looks like this:

junction box

When I bought it, I assumed that I could just screw/nail it to the side of the joist using those holes in the back. However, I can't do that because the screws for the cable clamp stick out the back by about 3/4"!

So, what is the correct way to mount this box to a 2×4? Or did I just buy the wrong thing?

Best Answer

Method 1

  1. Place the box where you want it and screw it lightly to the stud.
  2. Run the clamp screws in until they bite into the wood.
  3. Remove the box.
  4. At the marks left by the clamp screws, drill 1/4 inch relief holes about 1 inch into the stud to make room for the ends of the screws
  5. Reinstall the box.

Method 2

  1. Remove the existing clamps
  2. Knock out the inner discs on the sides (not the ones near the original clamps) by pushing one side with screw driver, then wiggling back and forth until it breaks off
  3. Install bolt on cable clamps like these (screw section goes on the outside) cable clamp
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