I am installing a new plastic box in a slightly different position in a bath in TX. I might be a bit short of wire and or space. The wire appears to be guage 12, and a bit hard to work with. It also does not seem to backstab into my new switches, I have to wind them around the screws, and so use even a bit more wire than was used before.

Is it ok to cut back the white exterior sheathing/sleeve back, so that individual wires will be easier to slide into the box and bend.

If not, then what is a practical way of pulling the sheathed wire back into the box? Can the holes on the box made larger than the cut out? or Can the wire be re-sheathed? or?

Here is what it will looks like. enter image description here

  • 1
    All the wires entering the box need to be protected by the sheathing until they are inside the box. None of yours are and you are setting up a dangerous hazard. Do not cut back any more sheathing
    – redlude97
    Jan 3, 2021 at 18:09
  • @redlude97 Yes, I found the Code saying at least 1/4 inch of sheathing must be intact inside the box to protect the interior wires from the nicks caused by the edge of box.
    – Maesumi
    Jan 3, 2021 at 18:18
  • @redlude97 Type this up as an answer.
    – JACK
    Jan 3, 2021 at 18:42
  • I edited he question to ask for alternative solutions.
    – Maesumi
    Jan 3, 2021 at 19:52
  • 2
    Backstabbing is not a good way to terminate on receptacles. Yes, it's approved, but just because you can doesn't mean you should. Since their introduction, most electrical circuit problems now relate to failed back stabbed connections. Wrapping around the screw is actually the BETTER way to terminate.
    – JRaef
    Jan 3, 2021 at 20:47

1 Answer 1


Despite your difficulties, the cable's sheath must come all the way into the box past the point of split, and be secured by the box's cable clamps.

You cannot modify the box to make things easier.

If you look closely at the photo, you can see where all 3 cables have crimp marks from where the previous clamps gripped them in the correct position. You need to do the same.

If you can't make it work any other way, I suggest you obtain a metal box of similar depth, which has a number of 3/4" circular "knockouts" on it, three on the side you need. Then, obtain these cable clamps.

enter image description here src enter image description here

Start by removing the large diameter thin "nut" on the backside of them (barely visible) - save that, you'll need it later.

Bunch the wires together for one cable, and push them through the hole. The side you are seeing in the photo goes first, i.e. on the wall side. Get it so at least 1/4" of intact sheath is past the edge of it (fully on good sheath and then some), and tighten down those screws.

On your steel box, bust out three knockouts on the correct side.

Thread all the cable's wires together and through the hole. Also put the nut, from earlier, over the cable's wires. Pull the cable into the steel box until the fitting's threads come through the hole. Spin the nut down onto the threads.

*Wasn't that easier? You got to put the clamp on the cable separate from putting the cable into the box. And putting the cable in the box, you got to work entirely on the accessible side.

Now, those nuts need to be torqued down, so get a flat screwdriver and put the blade on the "bump" on the left side and bap the back of the screw driver with some force, e.g. with your fist or something . That way you tighten the nut clockwise. That's how you do these.

The other boxes aren't working for you because they assume you have access to both the inside and outside of the box after it's mounted. You don't, actually.

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