How to Terminate Electrical Wire With Wire Caps

Gather Materials

You will need the following materials:

  • Electrical wires you are connecting
  • Wire strippers
  • Wire cutters
  • Wire nuts or wire caps of the appropriate size
  • Electrical tape (optional)

Make sure to turn off the power at the breaker before starting any electrical work.

Strip the Wires

Use the wire strippers to remove about 1/2 inch of insulation from each wire end you will be connecting. Take care not to nick or cut into the copper wire when stripping away the insulation.

Twist Wires Together

Twist the bare copper wires together until they are tightly joined with no frayed strands sticking out. Make sure you join wires of the same gauge together.

Select a Properly Sized Wire Cap

Choose a wire cap that is rated for the gauge of wires you are connecting. Wire caps come in different sizes to accommodate different gauges and number of wires. Place the twisted wires into the wire cap and turn the cap clockwise to screw it onto the wires.

Tighten the Connection

Hold the wires together firmly and continue twisting the wire cap until tight. Wiggle the wires to ensure they are making a solid connection inside the cap. The wire cap should be firmly screwed onto the bare wires with no loose play.

Check Your Work

Gently tug on the wires to verify they are securely held by the wire cap. If you can pull the wires free from the cap, then tighten further or use a bigger sized cap. The cap should grip the wires snugly.

Wrap with Electrical Tape (Optional)

For extra protection, you can wrap electrical tape around the wire cap. Stretch the tape tightly around the cap and wires to help seal out moisture.

Carefully tuck the connected wires into the electrical box. Secure with cable clamps if needed. Restore power once you have completed all connections. Test that the wires are energized and your connections are good.

Safety Tips

  • Make sure power is OFF before starting any electrical work.
  • Only connect wires of the same gauge.
  • Never overfill a wire connector.
  • Tug wires to confirm a tight fit.
  • Use properly sized wire caps.
  • Wrap tape around connections for moisture protection.

Terminating wire with wire caps is quick and effective when done properly. Follow the steps carefully for safe and working electrical connections.

Frequently Asked Questions

What size wire cap do I need?

Choose a wire cap rated for the gauge and number of wires you are connecting. They are color coded by size. If in doubt, go up a size to be safe.

How do I know if a wire cap is on tight enough?

A properly tightened wire cap will grip the twisted wires snugly. You should not be able to pull the wires out of the cap by tugging. Wiggle test wires to check tightness.

Can I use electrical tape instead of wire caps?

No, you should always use wire connectors like twist-on wire caps. Tape alone does not provide a secure and enclosed connection. Use tape only as supplementary insulation.

What if my wires are different gauges?

Ideally you should join wires of the same gauge. If you have no choice, choose a wire cap suitable for the smaller gauge wire. Alternatively use a pigtail splice of the smaller gauge wire.

Why do my lights flicker after capping wires?

This likely indicates a loose wire connection. The cap needs to be screwed on tighter. If that doesn’t work, the wires may be damaged and need to be re-stripped and re-capped.

Can I reuse old wire caps on new connections?

It’s best to use new wire caps on new connections. Old caps become brittle over time or may have been overstressed. Reusing damaged caps risks loose or poor connections.

How do I remove a stuck wire cap?

Try firmly wiggling and twisting the cap counterclockwise to loosen it. Needle-nose pliers can help grip and turn stuck caps. Take care not to damage wires when removing old caps.


Terminating wires with wire nuts or twist-on wire caps is an easy and reliable termination method. The key steps are stripping wires properly, twisting conductors together tightly, selecting the right size cap, and ensuring the cap is fully tightened. Taking the time to make solid connections ensures the wire caps perform their important role of insulating wires and preventing shorts or shocks. Follow basic electrical safety precautions, and test all connections before restoring power.