I have this cable running out of the wall in my garage to a light bulb. I'm looking to upgrade my garage lighting to actually be shop lights. I want to rerun the cable so that it comes out of the wall into an electrical box. The new cable will come out of the box into nonmetallic liquidtight conduit which will run to the center of the garage ceiling terminating at an outlet. The roof of the garage is unfinished.

I attached some images so you can see what it looks like right now. The wire currently just goes from the wall through a joist to a light socket.

My question is do I need to use a wire clamp for the wire coming out of the wall or can I just screw the box to the wire with the punch out over the wire coming out of the wall.

This is what I mean by clamp.

enter image description here

Here are pictures of the wire coming out of the wall to the light socket.

Wire coming out of wall Wire to light socket


2 Answers 2


No, you don't use those where wires enter a wall.

Those clamps are used when the wire is transitioning into a box or panel. The purpose is to protect the wire from the relatively sharp edges of the box/panel and to prevent undesired movement after installation.

  • So is it okay if I just put the over the where the wires come out of the wall. Or should I put the box next to wires coming out of the hole and have them go into the side of the box. The box will be used as a transition into conduit. Feb 5, 2021 at 6:59
  • @MichaelTurnwall How do you intend to clamp the wire where it comes through the back of the box? Does the box have an integral clamp suitable for a cable coming in from the back?
    – HABO
    Feb 5, 2021 at 19:31

Mount the box on the joist near where the cable comes through. Then you can properly staple the cable outside the box and clamp it as it enters the box.

Fiddling about with a knockout bushing and trying to sneak the cable in through the back of the box doesn't seem to offer any benefits.

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