5 Different Types of Electrical Extension Cords

Electrical extension cords have become a household and workplace staple due to many small but indispensable issues. Extension cords come handy when there are insufficient plug points. They also help when plug points are located on the other side of the room.

However, it can be challenging to find the right extension cord, especially when we are new to them or have many devices of varying plug characteristics around. If you have never bought an extension cord before, a basic understanding of its types is a must for ensuring safety.

An oft used household extension cord is available in 16-gauge, 14-gauge, 12 gauge, and 10 gauge extension cord sizes. Apart from this, there are also extension cords specifically designed for indoor or outdoor use with varying cord lengths.

The length of an extension cord decides its resistance too. There are various aspects that we should know about extension cords before finalizing one. Before picking an extension cord, we should be clear about:

  • The equipment to which we would connect it
  • The location (indoor, outdoor) where we intend to use the cord

Selecting the right extension cord is not only about meeting your needs, but it is also about maintaining safety. Incorrect usage of electrical cords might lead to hazardous results.

Extension Cord Types and Selecting the Right One

You can classify extension cords into three broader categories:

  1. Heavy-duty extension cords
  2. Medium duty extension cords
  3. Light-duty extension cords 

They can also be classified according to their length, gauge type, and plug type. Take a look at what these classifications mean:

1. Heavy-duty extension cords

These types of extension cords are suitable for drawing up to 15 amps of current. They usually have a third wire or a third plug prong, which is used for grounding. The plugs of these extension cords also have three slots to accept grounded appliances. 

Generally, these extension cords fit equipment such as heating appliances that draw up to 10-15 amps of power. 

Here is a table that shows the design of the medium-duty extension cord gauge wire depending on their cord length:

14-gauge25 feet
12-gauge50 feet
10-gauge100 feet

2. Medium-duty extension cords

This extension cord fits for appliances such as televisions and computers that draw up to 10 amps of current. They usually have a three-pin plug type and are grounded. Medium-duty extension cords also have a slot that accepts three-pin devices as well. 

Here is a table that shows the design of the medium-duty extension cord gauge wire depending on their cord length:

16-gauge25 feet
14-gauge50 feet
12-gauge100 feet

3. Light-duty extension cords

This type of extension cord goes well with devices that can draw up to 7 amps of current. Light duty extension cords usually have a two-prong plug, which means they do not have a grounding wire. Hence, we should not use them with other appliances with stranded wire (that is, appliances with a three-prong plug). 

These cords are compatible only with lightweight appliances such as lamps, clocks, phone chargers, etc.

Here is a table that shows the design of the light-duty extension cord gauge wire depending on their cord length:

18-gauge25 feet
16-gauge50 feet
14-gauge100 feet

When using an extension cord with any appliances, it is always best to check whether that appliance is compatible with the type of extension cord you have. In such situations, the manual of the instrument might be of significant help to understand the compatibility. In some cases, you should never use some devices with an extension cord.

4. Extension Cord Length and Gauge

The length and wire gauge of extension cords differ based on their intended functionality. The wire gauge of the extension cord is the thickness or the diameter of the wires. This affects how much the wire heats up and how much power it can carry. 

The length of the extension cord is crucial because it affects how much voltage is lost. You can also term this as the voltage drop due to the electrical resistance of the wire. The longer the cord, the greater is the voltage drop.

5. Classification based on the type of plug

Generally, extension cords either have a two-prong plug or a three-prong plug. The third prong gets designed for grounding. This means that if any loose or faulty wire comes in contact with the extension cord, the third prong can direct the electricity directly to the ground rather than our hand.

Hence, it is best to purchase extension cords with a three-prong wire for safety, unless a light-duty extension cord is sufficient to fulfill your needs.


When purchasing an extension cord, ensure that it is classified for indoor or outdoor use, depending on where you will be using it. Purchasing an extension cord with a Ground Fault Circuit Interrupter (GFCI) also helps add another layer of safety to your extension cord. GFCI ensures that the power to the extension cord is cut off if a fault occurs with the grounding. Understanding the differences between the various types of extension cords makes it easier to select one that fits our needs aptly.