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How to Wire or Repair an Extension Cord

With the summer outdoor season upon us, we’re going to discuss extension cords, and how to wire or repair them in the event they become damaged.  Extension cords are an essential item to have around the home, yard, or garage.  We use them for everything from the connection of some temporary decorative lighting, like patio lights or Christmas lights, to extending the power supply to facilitate the use of things like electric hedge trimmers, lawnmowers, and construction tools.

When choosing the correct extension cord for the application, here are some things to consider.

Ensure the cord is of sufficient size to supply the tool or electrical load that you will be using.  The more current you require, the heavier the cord needs to be.  The longer the cord, bigger is better as well.

Always choose the correct cord for the application.  All cords are rated for their conditions for use, like indoor or outdoor.

Extension Cord

Last but not least, inspect the cord to ensure that it is in good condition.  In this post I am going to focus on the repairing of a cord should it need attention!

How To Repair a Damaged Extension Cord

For various reasons, extension cords can become damaged.  Maybe you accidentally rolled the electric lawnmower over it causing some major damage, or maybe you drove over it with the car causing only slight damage like a nick in the outer insulation.

If the rest of cord is in good condition (other than this new damage), here’s the options for repair:

  • If only the outer jacket is damaged (not likely if it was a victim of a lawnmower encounter), then you might be able to do a simple repair with electrical tape.  This is not the best answer, but if you are sure that no damage has occurred to the conductors and their insulation, then this is an acceptable repair.  Use good quality electrical tape, and begin close to the damaged area of the cord.  Cover the crack or cut in the outer jacket with a layer of tape, over-lapping the repair area by an inch or so on either side of the damage.  Then go back and forth 3 or 4 times with a layer of tape, each time over-lapping where you last stopped so that you have a new layer of contact of the tape to the jacket, ensuring a water-tight seal.


Extension Cord Repair

  • If the insulation of any of the conductors has been damaged or the conductors are exposed or cut, and it’s within a few feet of one end, then you can cut off the damaged cord and put on a new cord end, either a male cord cap (plug), or a female cord end (connector body), whichever the case may be.


Damaged Extension Cord

  •  If the damage is somewhere closer to the middle, then cut out the damaged section and make 2 cords from the one damaged one.  You would need to purchase two new cord good quality cord ends, one female (connector body), and one male (plug).


Here’s how to properly install a new cord end:

Cut out the damaged area of the cord entirely, and then strip the outer jacket the correct distance to ensure that the jacket of the cord will extend inside of the cord cap body far enough that the cable clamp will tighten down of the outer jacket, and not on the individual conductors.

Wiring a Damaged Extension Cord

Then put the housing of the cord cap on by inserting the cable through the cord clamp and housing, and then terminate the stripped conductors on the correct terminal connections.  Green goes on green, white on the silver, and black on the brass terminal.  Tighten firmly and tug in each conductor to ensure that you have a good connection.

Wiring a Damaged Extension Cord - Connecting the Terminals

Then slide the housing back over the connections, lining up the slot to the groove, or using whatever means provided by the cord manufacturer to correctly line up the housing with the screws or fastening method to join the housing to the body and finish that connection.  There are many different types and styles of cord ends on the market.  Then tighten the screws for the cable clamp again making sure that the outer jacket is inside the connector body.

How to Wire an Extension Cord

So there you have just a few options for the repair of a damaged extension cord rather than just discarding the damaged cord in the trash!  To watch the complete video demonstrating the steps to wiring and repairing an extension cord, view below:

I’m Terry Peterman, the Internet Electrician® at

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The Basics of Household Wiring DVD

"If you're looking for a good reference to help you understand simple home wiring, I personally recommend 'The Basics of Household Wiring' DVD".

Terry Peterman, the Internet Electrician
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