How to Repair a Broken Extension Cord

Assess the Damage

The first step when repairing a broken extension cord is to assess the damage. Carefully inspect the cord to determine exactly where and how it is damaged. Some things to look for:

Fraying or exposed wires. This usually occurs near the plug or connector ends and indicates the insulation has worn away. Exposed copper wires are dangerous and the extension cord is unsafe to use.
Cuts, nicks, or punctures in the insulation. Damage to the outer plastic insulation exposes the inner wires and poses a shock hazard. Even small cuts in the insulation can eventually lead to fraying and exposed wires.
Cracks or damage to the plug or connector. Cracks and damage to the hard plastic body of the plug or connector ends makes it unsafe for use. Damage here can indicate issues with the internal wires and connections as well.
Crimped or crushed sections of cord. If the cord has been crimped or crushed under a heavy object or door, there may be internal damage to wires even if the outer insulation looks intact.

Carefully running your hand along the entire length of the cord can help detect any damage or imperfections. Visually inspecting both sides of the cord is important to find any cuts, cracks or frays in the insulation.

Gather Supplies for Repair

Once you've identified the location and extent of damage to the cord, gather the necessary supplies to repair it. Basic supplies include:

Electrical or vinyl tape. Used to wrap and insulate exposed wires or damaged sections of cord. Electrical tape is best for repairs, but standard vinyl tape can work in a pinch.
Wire connectors or crimp connectors. Used to reconnect severed internal wires. Wire nuts twist onto the wires to connect them, while crimp connectors use pressure to hold wires together.
Replacement connector or plug (optional). If the damage is to the plug or connector, you may need to replace it completely. Make sure to get the right type and amperage rating.
Cable jacket repair kit (optional). For repairing insulation damage along the length of the cord. Contains heat shrink tubing to patch cuts and abrasions.
Utility knife. For trimming frayed insulation or cutting away damaged sections of cord.
Wire strippers. To strip away insulation and expose copper wires for reconnecting.
Needle nose pliers. Helpful for manipulating and connecting small wires.

Make the Repair

With your supplies gathered, you're ready to repair the damaged extension cord:

Trim away any frayed or damaged insulation using the utility knife or wire strippers. Trim back far enough to reach solid, undamaged insulation.
Strip away insulation on inner wires using wire strippers. Expose approx 1/2 inch of copper wire to reconnect.
Reconnect the severed wires using twist-on wire connectors. Make sure insulation does not extend inside the connector. Alternately, use pliers to crimp a crimp connector.
Wrap exposed sections of wire with electrical tape to add insulation. Wrap tightly and extend tape onto undamaged insulation.
If needed, use heat shrink tubing to patch small insulation gaps or nicks. Cover damaged area fully with the tubing and apply heat to seal it.
For connector or plug damage, replace the entire unit. Carefully detach old plug and attach wires to the new plug's terminals in the correct positions.
Test the repaired cord before putting it back into use. Plug it in with no appliances attached and check for proper function.

Tips for Prevention

Here are some tips to help avoid damaging your extension cords in the future:

Don't overload cords with more wattage than they are rated for. This can lead to overheating and insulation damage.
Unplug cords properly by the plug itself instead of yanking by the cord. Pulling on the cord damages the connections.
Don't pinch cords in doors or windows as this can crush the insulation and wires.
Keep cords clear of foot traffic to avoid tripping hazards and damage.
Store cords properly by coiling loosely rather than twisting tightly. Hanging cords can help keep them off the ground and floor.
Replace old and worn cords that are showing any signs of damage or fraying.

By following these prevention tips and properly repairing any damage, your extension cords can enjoy a long and safe operational life. Be sure to take your time making repairs and use the right materials to fix cords properly.