What is Insulation in a Cable? Ultimate Guide

What is Insulation in a Cable? Ultimate Guide

You may know a little bit about what insulation in a cable is and what is it used for? But do you know all the minor details about cable insulation?

The insulation within commercial and industrial cables is designed to protect you from electrical hazards. It’s important that you know how to identify the different types of insulation and what types of materials you should use for your projects. Let’s take a look at some of the most common types of insulation in ethernet network cables.

What is cable insulation?

Insulation in cables protects the core from short circuits, electromagnetic interference (EMI), and crosstalk. The conductors are wrapped in sheaths made of plastic, which helps to keep the cable safe and signal transmission flawless. 

The bundle of conductors is then wrapped in another insulation that is also called a cable jacket. It keeps the overall cable intact and ensures the safety and optimum performance of the cable. 

Types of cable insulation

There are hundreds of cable insulation types and the numbers are always growing. But the most commonly used ones are only two. Polyvinyl Chloride and Fluorinated Ethylene Polymer. 

PVC: The most common type of cable insulation is Polyvinyl Chloride (PVC). It is a cheap plastic compound that is resistant to extreme weather and heat. PVC insulation is mostly used in making cable jackets. Such as jackets for bulk ethernet cables.  

FEP: Fluorinated Ethylene Polymer is a high-end plastic material that is used widely in making insulation for networking cable insulations and jackets. It is highly resistant to flame, heat, UV light, extreme temperatures, and humidity. 

It is also renowned for not emitting smoke if it catches fire. That’s what makes it the best for indoor use as cable insulation. 

Best cable insulation in ethernet cables

The best insulation in ethernet cables is made up of FEP materials. Plenum jackets are the prime example of such insulations. There are several reasons for that. 

Firstly, for ethernet network cables to transmit data at high speeds, EMI and crosstalk need to be as little as possible. FEP insulations with their thick and intense build meet this requirement pretty well.

Secondly, ethernet cables can heat up while performing at optimum capacities. This could translate into a fire catastrophe if the cable insulations are not resistant to heat. FEP insulations, such as those used in manufacturing plenum-rated jackets, are highly resistant to heat. 

And they are also capable of resisting UV light. Low temperatures, dust, and water. These properties make this type of insulation the best type for ethernet cables. 

Thirdly, FEP insulations are flexible. Which makes ethernet cable installation very easy, if they are insulated with FEP. 

Does insulation in ethernet cables matter?

Insulation in bulk ethernet cables certainly matters. As mentioned earlier, ethernet cables without proper insulation wouldn’t function smoothly or wouldn’t function at all. The reason behind that is the part that insulation plays in data transmission over ethernet cables. 

First, the insulation prevents the contact of conductors in an ethernet cable. It is vital for the fast and efficient transfer of data. Secondly, the insulation protects the conductors from their surroundings/environment. That is an extremely important reason because, without the outer insulation/jacket of ethernet cables, they would be complete.  


The cable insulation is one of the most important components of ethernet network cables, and of all types of cables in general. It ensures the proper functionality of cables. In ethernet cables, it ensures that the conductors do not come into direct contact with each other and different interferences do not affect the signal transmission.