Electrical Wire Caps: Safe Way to Cut Wire at Mid-Point

Electrical wire caps are the safe, efficient, and code-compliant method of dealing with electrical wires that are cut at mid-point and which must remain live.

One byproduct of removing a wall or taking down a ceiling is the stray electrical wires. All walls have electrical outlets; ceilings have at least one ceiling light; both walls and ceilings can have wires that are traveling to other locations. This means that you really cannot avoid stray wires. What should you do to safely and easily deal with them?

  • 01 of 14

    Electrical Code: Cap All Loose Wires That Remain Live

    Craftsman working at construction site of new building
    Dreet Production / Getty Images

    In most cases, you cannot strip back the wires all the way to the service panel (circuit breaker board). Doing so would mean removing wall and ceiling drywall and would be wasteful and ineffective.

    The answer is fairly simple: you leave the wires in place, capping them with wire nuts. Then you enclose the ends of the wires in a junction box that is covered with a solid face plate. This action is compliant with most electrical codes.

  • 02 of 14

    Wrong Way To Cap Electrical Wires

    Wrong Way to Cap Wires
    Wrong Way to Cap Wires. Lee Wallender

    There are many wrong ways to cap electrical wires. Homeowners and electricians alike frequently run across wires that are improperly spliced and capped. Junction boxes might be hidden behind ceiling or wall drywall.  Even worse, stray wires might be secured with electrical tape and then hidden behind the wall. 

    All wires need to be contained in junction boxes. All junction boxes need to be at the level of the finish surface (wall, ceiling, etc.), so that they can be seen and accessed.

    Tools and Materials Needed

    • Junction Box
    • Wire nuts
    • Electrical tape
    • Cable ripper
    • Wire stripper
    • Screwdriver (Flat and Phillips)
  • 03 of 14

    Turn Off and Seal Over Circuit Breaker

    Seal Circuit Breaker
    Seal Circuit Breaker. Lee Wallender

    Before taking down the wall, you must shut off the circuit breaker.  Increase your margin of safety by laying electrical tape across the circuit to prevent anyone--even you--from accidentally flipping on the breaker.

  • 04 of 14

    Cut Box Opening in Drywall

    Cut Box Opening
    Cut Box Opening. Lee Wallender

    Since you've removed the wall, you don't have anywhere to put those wires now. You'll need to find the closest available spot in existing wall or drywall to place those stray wires. This means looking backwards in the wire run.

    Once you have a location, cut an opening in the drywall with your jab saw, reciprocating saw, or RotoZip. Make sure the opening is a close fit.

    Old-Work Junction Boxes

    In many installations, there is no way to fasten a conventional junction box, The solution is to use what is called an old-work or remodeling box, which attaches to the drywall with "wings" that grab the back of the drywall. Because the wire is Romex (NM), you can use a plastic box.

    Continue to 5 of 14 below.
  • 05 of 14

    Test-Fit Box in Drywall Opening

    Test Box in Opening
    Test Box in Opening. Lee Wallender

    If you did this correctly, the box probably will not fit on this first go-around. The reason for making this a tight fit is because these old-work boxes don't have a lot of tolerance for error:  just two narrow tabs at top and bottom hold the box into place on the front side.

  • 06 of 14

    Shave Off Excess Drywall From Opening

    Shave Excess Drywall
    Shave Excess Drywall. Lee Wallender

    If the hole is too small, use your jab saw to shave off excess drywall. If you plan to do a lot of drywall work on your home, it will be worth your while to purchase a drywall shaver. This metal tool, which looks like a cheese grater, is very effective at grinding down small sections of drywall.

  • 07 of 14

    Fit Wire Into Old-Work Box

    Fit Wire Into Box
    Fit Wire Into Box. Lee Wallender

    Pop open one of the access holes and pull the cable through that access point. For metal junction boxes, wiggle out the metal tab with a screwdriver and then screw a restraint strap in place.

  • 08 of 14

    Screw Old-Work Box Into Drywall

    Screw Box Into Place
    Screw Box Into Place. Lee Wallender

    With your manual Phillips screwdriver or cordless drill, screw the old-work box into place. This forces the "wings" to pull forward and cinch the box tight in the opening.

    If using a drill, set the drill's torque low as it is easy to strip these screw heads or break the wings.

    Continue to 9 of 14 below.
  • 09 of 14

    Rip Casing From Cable

    Strip Cable
    Strip Cable. Lee Wallender

    With your cable ripper, pull outward three or four times to create light scores in the cable casing.  

  • 10 of 14

    Strip Casing From Individual Wires

    Strip Wire Casing
    Strip Wire Casing. Lee Wallender

    You don't have to expose the wire ends if they won't be powering any devices. But if you know that you will be attaching a device before long, you can do yourself a favor and strip the wires now.

  • 11 of 14

    Cap With Wire Nuts and Tape Together

    Cap and Tape Wires
    Cap and Tape Wires. Lee Wallender

    Cap the wire ends with wire nuts. Tape each nut onto its respective wire with electrical tape. Tape the two wires together.

  • 12 of 14

    Test Power With Voltage Tester

    Test Power to Wires
    Test Power to Wires. Lee Wallender

    Flip the circuit breaker on again and, with your voltage tester, make sure that power is still flowing to the box.

    Continue to 13 of 14 below.
  • 13 of 14

    Fold and Push Wires Into Box

    Push Wires Into Box
    Push Wires Into Box. Lee Wallender

     Turn the circuit breaker off again. Carefully fold the wires into the box.

  • 14 of 14

    Screw Face Plate Onto Box

    Put Face Plate on Box
    Put Face Plate on Box. Lee Wallender

    Screw the box's face plate into place.