One common byproduct of removing a wall or taking down a ceiling is stray electrical wires. If the wires, or circuit cable, will be not be used to feed new outlets, light fixtures, or other permanent devices, you need some way to deal with the wires. The safest way to take wiring completely out of service is to disconnect it from its power source and remove all of the wiring so that it won't confuse or pose any risk to future remodelers. But if you don't want to discontinue the circuit entirely, or it is problematic to remove the cable, you can safely cap the wires and terminate the cable inside a junction box.
Terminating the electrical wires and capping them in accessible electrical boxes is the safe, efficient, and code-compliant method of dealing with electrical wires that will remain energized. All wires that are terminated or spliced need to be contained in junction boxes, and the junction boxes must be at the level of the finish surface so that they can be seen and accessed.
Turn off the power to the circuit and confirm the power is off with a voltage tester before touching any wires or moving any circuit cable.
Equipment / Tools
- Non-contact voltage tester
- Drywall saw
- Cable ripper
- Utility knife
- Wire strippers
- Electrical tape
- Junction box with blank cover
- Wire connectors
Turn Off the Circuit Breaker
Shut off the power to the electrical circuit by switching off the appropriate breaker in your home's service panel (breaker box). If you've been demolishing a wall or ceiling in the area, the power should already be off, but double-check that the correct circuit breaker is switched off for the cable you will be terminating. For added safely, place electrical tape across each circuit breaker switch to prevent anyone, even you, from accidentally flipping on the breaker.
Test for Power
Return to the work area and test all wiring you will be working on with a non-contact voltage tester. Touch the tester probe to all sides of the cable jacket and to the end of each individual wire. The tester should indicate no voltage. If it detects voltage, return to the service panel and shut off the correct breaker, then retest the wiring.
Choose a Junction Box Location
Choose a location for the junction box that is easily accessible and where the circuit cable can feed into the box and extend past the front of the box at least 8 inches.
Cut the Box Opening
Position the front of the box against the wall or ceiling surface in the desired box location, and trace around the outside edge of the box with a pencil. Carefully cut along the traced outline with a drywall saw.
If it is difficult to access a wall stud or ceiling joist to anchor the new box, use an old-work or remodeling box, which attaches to the drywall with wings that grab the back of the drywall.
Feed the Cable Into the Box
Pull the circuit cable through the box hole. If there is a lot of excess cable, trim it to length so that roughly 8 inches of the cable will extend beyond the front of the box when is installed. Gently pry up the clamping tab over one of the holes in the back of the box with a flat-head screwdriver. Push the cable through the hole. If the box does not include clamping tabs, install a cable clamp to secure the cable to the box.
Install the Junction Box
Fit the box into the hole so its front edge is nearly flush with the wall or ceiling surface. Pull out more cable, as needed, so it extends about 8 inches from the front of the box.
On an old work box, tighten the two mounting screws so that the wings on the box pull forward, cinching the box tight against the drywall. It's best to do this with a manual screwdriver so you don't overtighen the screws and strip these screw heads or break the wings.
If you're using a conventional, or "new work," box, mount the box to the wall or ceiling framing with the provided screws or nails.
Prepare the Wires
Use a cable ripper to cut the cable sheathing a few inches from the cable's end, then strip back the sheathing and trim off the excess with the utility knife or scissors. It is not necessary to strip the insulation from the individual wire ends since the wiring will not be powering any devices. However, if the ends of the wires are mangled, snip them back until you reach a smooth section.
Cap the Wires
Cap the wire ends with wire connectors, or wire nuts. Choose the appropriate size of nut for an individual wire, and twist each nut clockwise while pushing it onto the wire, until the nut is very tight. Tug on each nut to ensure it is secure.
For additional safety, you can tape each nut onto its respective wire with electrical tape, then tape the wires together. Bare copper ground wires do not need to be capped.
Install the Box Cover
Gently fold the wires accordion-style and push them into the box. Be careful not to detach the wire nuts. Attach a blank (no holes) cover to the electrical box, using the provided screws.
It is now safe to restore power to the circuit, if desired.