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In an Extension Cord, What is the Conductor, and What is the Insulator

Written by Edwin Jones / Fact checked by Andrew Wright


Aside from the plug and outlet, an extension consists of different parts. It has a conductor, an insulator, and a cover jacket.

However, if you are not familiar with electricals, you may ask, “In an extension cord, what is the conductor, and what is the insulator?”

This is why I made this article—to tell you about the parts of the extension cord and their purpose.

What Parts of Extension Cord Are the Conductor and Insulator?

It is very easy to define which are the conductors and insulators in an extension cord. The wire inside is the conductor, while its coating is the insulator.

Furthermore, the metal prongs on the plug and outlet are also conductors, and the thing that covers them is also an insulator. These are some of the basic parts names of an extension cord.

When you understand what they are, you can wisely choose which type of electrical cord is safe and best suits your needs.

If you want to know more about the parts of a power cord or electrical cords, here is some brief information about them.

1. Conductor


A conductor in physics is a material or substance that enables electricity to flow freely through it. It is the current carrier that is primarily in the form of metals such as copper, aluminum, silver, and more.

Most manufacturers use copper wires for making extension cords. This is because copper is a good electrical conductor, widely available, and produces less resistance than other types.

Furthermore, copper can form stranded wires for bendability, which are necessary for appliances like vacuum cleaners.

Another factor to consider is the thickness and number of conductors in an extension cord. It is critical since these determine how much electricity can run through the extension and how safe it is.

The most common extension cord gauges for residential use are 16, 14, 12, and 10 AWG. A greater diameter conductor usually has a smaller AWG, which means a smaller AWG has a higher power rating.

Choose a cable with a larger conductor if you need to operate high-powered devices through an extension cord. You can also consider one with three prongs, which contain a ground connection for safety.

Without a ground conductor, anyone who touches a circuit with a ground fault can get electrocuted.

2. Insulator


The insulator is the opposite of a conductor since it will not allow electricity to go through. The materials that are insulators are mostly plastic or polymer.

Regarding their function, insulators protect the conductor or wire from corrosion-related damage. They also keep separate conductors within the extension cord from coming into contact with each other, thereby preventing electrical problems.

Color-coded wire insulation makes it simple to determine which conductor is hot, neutral, and ground. Inside the extension cable, you can see black for the hot wire, white for the neutral wire, and green or bare for the ground.

In addition to wire insulation, there is also a sheathing or cover jacket for the conductors. Normally, this cover jacket is made of plastic, rubber, or vinyl.

This sheathing also helps determine whether the extension cord is outdoor or indoor. There is a letter code used for various types of extension cords.

For general household appliances, use a power cord bearing the letter “S.” However, if you require an electrical cable for outside usage, consider one with the letter “W,” which indicates that it is rated for outdoor applications.

Is an Extension Cord a Conductor or Insulator?


An extension cord has both a conductor and an insulator. The conductor is the wire inside the covers, while the insulators are the plastic or rubber that covers the conductor.

Is Steel Conductor or Insulator?

Steel is a type of metal and is also a good conductor of electricity. However, this material is not popular since it is too hard to mold. It is only used as an enclosure for other conductors or large structures.


Being able to answer the question “In an extension cord, what is the conductor, and what is the insulator?” will help you find the suitable electrical cable for your needs.

Furthermore, considering factors that make power cords safe is also a big help in selecting the right extension cord.

You can easily purchase one for high-power devices that allows outdoor usage. However, if you choose to make a DIY cord, find a good conductor material and covering.

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