110 Extension Cord Wiring Diagram: The Ultimate Guide

Extension cords are essential tools in every home, but using them incorrectly can lead to electrical hazards. Many people do not know how to wire an extension cord correctly, and this can be dangerous. In this guide, we will discuss how to wire a 110 extension cord, including the necessary tools, step-by-step instructions, and safety precautions to take. Keep reading to learn more!

Tools Required

Before you start wiring your 110 extension cord, you need to have the following tools:

  1. A pair of wire strippers
  2. A pair of scissors or utility knife
  3. A soldering iron with rosin-core solder
  4. A heat gun or lighter
  5. A multimeter (optional but recommended)

A pair of wire strippers

Wire strippers are tools used to remove the insulation from the ends of wires. You will need wire strippers to strip the insulation off the ends of the extension cord wires.

A pair of scissors or utility knife

You will need either scissors or a utility knife to cut the extension cord to the required length.

A soldering iron with rosin-core solder

You will need a soldering iron to connect the wires together. A rosin-core solder is the best type of solder to use as it contains flux, which will help the solder flow smoothly and prevent oxidation.

A heat gun or lighter

You will need a heat gun or lighter to shrink the heat shrink tubing, which will protect the connection between the wires.

A multimeter (optional but recommended)

A multimeter is an electrical testing tool that measures voltage, current, and resistance. Although not required, it is recommended that you use a multimeter to test the continuity of the wires after making the connections.

Step-by-Step Instructions

Now that you have gathered the necessary tools, here are the steps to follow when wiring your 110 extension cord:

Step 1: Cut the Extension Cord to the Required Length

Before starting, measure the distance between the device you want to plug in and the electrical outlet. Cut the extension cord to the required length using a pair of scissors or a utility knife.

Step 2: Strip the Insulation from the Ends of the Wires

Using wire strippers, strip about 3/4 inch of insulation from both ends of the extension cord wires. Twist the exposed wires together.

Step 3: Solder the Wires Together

Heat the twisted wires with the soldering iron and apply rosin-core solder until the wires are covered. Make sure the solder flows smoothly and there are no air pockets. Allow the solder to cool for a few seconds.

Step 4: Cover the Connection with Heat Shrink Tubing

Slide a piece of heat shrink tubing over the soldered connection. Use a heat gun or lighter to shrink the tubing until it is tight and secure.

Step 5: Test the Continuity of the Wires (Optional)

If you have a multimeter, use it to test the continuity of the wires. This will ensure that the connection is strong and that there are no breaks in the circuit.

Step 6: Put the Extension Cord Together

Once the connection is secure, put the extension cord back together. Use electrical tape to secure the wires in place.

Safety Precautions

When working with electricity, it is always important to take safety precautions. Here are some things to keep in mind:

Wear Protective Gear

Always wear protective gear such as gloves and goggles when working with electricity.

Turn off the Power

Before you start wiring your extension cord, make sure the power is turned off. This will prevent any electrical shock or injury.

Use the Right Tools

Use the right tools for the job. Using the wrong tools can be dangerous and lead to electrical hazards.

Inspect Cords Regularly

Inspect your extension cords regularly. Look for any signs of wear, such as frayed cords or exposed wires. Do not use the cord if it is damaged.


Q: Can I wire a 110 extension cord without a soldering iron?

A: Yes, you can use wire connectors to connect the wires together instead of soldering them. However, soldering provides a stronger connection.

Q: Can I use electrical tape instead of heat shrink tubing?

A: No, electrical tape is not recommended as it can come loose over time. Heat shrink tubing provides a more secure and long-lasting connection.

Q: How do I know if my extension cord is too long?

A: The longer the extension cord, the more voltage drop it will experience. This can lead to overheating and electrical hazards. A good rule of thumb is to use an extension cord that is not longer than 100 feet.

Q: Can I connect multiple extension cords together?

A: No, this is not recommended as it can cause voltage drop and increase the risk of electrical hazards. Instead, use a single, longer extension cord that can reach your device.

Q: What should I do if my extension cord gets hot?

A: If your extension cord gets hot, unplug it immediately. This is a sign of an electrical hazard, and using the cord can lead to a fire or injury.


Wiring a 110 extension cord is a simple and easy process if you follow the steps outlined in this guide. Make sure you have the necessary tools, take safety precautions, and remember to test the continuity of the wires. By following these tips, you can ensure that your extension cord is safe and reliable.