How to Terminate Electrical Wire With Wire Caps

Wires in electric box

The Spruce / Margot Cavin

Overview
  • Working Time: 30 mins
  • Total Time: 30 mins
  • Skill Level: Intermediate
  • Estimated Cost: $5 to $10

When you remove or open a wall or a ceiling, you may encounter stray electrical wires. The wires may have lead to an outlet or a light that has been taken out of commission. Or the previous owners may have buried the wires behind drywall—an extremely dangerous practice.

The ideal approach is to remove all of the wires. But unless you intend to remove drywall up to the electric service panel, this usually isn't possible. The next-best approach is to terminate the electrical wires with wire caps (wire nuts). All terminated electrical wires are trimmed, capped, and safely enclosed in an accessible surface-flush electrical box.

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Watch Now: How to Terminate Electrical Wire With Wire Caps

Codes and Regulations

Terminating an electrical wire with a wire cap is not, by itself, a project that typically requires an electrical permit. But it usually is part of a larger project that does require an electrical or building permit.

When to Terminate Electrical Wire With Wire Caps

It is always easiest to work with electrical wire before the drywall has been installed on the studs. If enough walls are open, you may be able to pull back the electrical wire all the way to an intermediate point or to its starting point.

The intermediate point can be another electrical box located in the direction of the service panel. If possible, it makes more sense to strip back the wire toward that upline electrical box and use that as your termination point than to install an additional box with capped wires and a blank wall plate.

Even better would be to strip back the wire to its original starting point: the circuit breaker at the service panel. Unless this is a whole-house remodel with drywall removed, this is rarely possible.

Safety Considerations

Terminated, capped electrical wires should never be buried behind drywall, whether loose or in an electrical box. The leading edge of the electrical box must be flush with the drywall.

tools for Terminating Electrical Wire With Wire Caps
The Spruce / Margot Cavin

What You'll Need

Equipment / Tools

  • Wire stripper
  • Non-contact voltage tester
  • Flat-head screwdriver
  • Utility knife

Materials

  • Electrical box
  • Electrical tape
  • Wire nuts (wire caps)
  • Blank wall plate for the box

Instructions

  1. Shut Off the Power

    Shut off the power to the electrical circuit by switching off the appropriate circuit breaker in your home's electric service panel or circuit breaker box. For added safely, run a strip of electrical tape across each circuit breaker switch involved with this project to prevent anyone, even you, from accidentally flipping on the circuit breaker.

    At the electrical box, test all wiring you will be working on with a voltage tester. Touch the tester probe to all wires and to all parts of each wire within the box. 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.

    Test Wires With Voltage Detector
    The Spruce / Margot Cavin
  2. Prepare the Bare Ends of the Wires

    With the electrical wire stripper, cut off any bare ends of wire down to the wire coating to tidy them up. Strip the plastic coating off the ends of the wires. Make sure that you have about 1/2-inch of clean, straight wire at the end.

    Cutting wires using an electrical wire stripper
    The Spruce / Margot Cavin
  3. Place Wire Nuts on the Wires

    Turn the plastic wire nuts (also called wire caps) onto the ends of the wires. Use the appropriate size of wire nut for the wire. Wire nuts that are too big will not sufficiently grip the wire and will fall off. Wire nuts that are too small may initially feel like they are on the wire, but they, too, may fall off. Turn the wire nut clockwise.

    Bare copper ground wires do not need to be capped. Similarly, BX cable's metal armor sheathing, which conducts to ground without the need for an additional ground wire, may be left alone.

    Place wire caps on electrical wires
    The Spruce / Margo Cavin
  4. Add Electrical Tape to Individual Wires

    Tape each wire nut onto its respective wire with electrical tape.

    Adding electrical tape to wires
    The Spruce / Margot Cavin
  5. Push the Wires Into the Box

    Push the wires back into the box. Check to make sure that your assembly has not come apart before proceeding to the next step. Any exposed copper wire may cause an electrical short or fire.

    Wires in electrical box
    The Spruce / Margot Cavin
  6. Add the Blank Wall Plate to the Box

    Attach a blank wall plate to the electrical box, using the provided screws. Some blank wall plates can be painted over.

    If the terminated wires are part of a working circuit, it is now safe to restore power to the circuit. If the terminated wires comprise an entire circuit alone, there is no need to turn on the circuit.

    Electrical box wall plate
    The Spruce / Margot Cavin