What is insulation in cable? Ultimate Guide

What is the first thing that you notice in an ethernet networking cable? It is almost always the cable jacket, which is also called the cable insulation. The importance of cable insulation is pivotal for the proper functioning of the cable. And in this article, we will discuss the different types of cable insulations, their uses, etc.      


Cable insulation: Definition

A Cable insulation/jacket prevents electric current from leaking out into the surrounding cables and other conductive materials. It protects a cable against the uncertain conditions of its environment. In bulk ethernet cables, it  comes in different types. For instance, riser, PVC, and plenum. 

Now the above-mentioned jackets are not the only types of insulations. The sheaths underneath the outer jackets are also a type of  insulation that prevent the conductors from electromagnetic interference (EMI) and external crosstalk, and from internal crosstalk. 


Types of Cable Insulation

The following are the three main types of cable insulations which are also called jackets. 



Communications multipurpose plenum (CMP) is the top-notch cable jacket with the highest fire safety and performance standard rating. It is manufactured with self-fire extinguishing material that prevents high temperatures from igniting fires. However, in the most unlikely scenario of catching a fire, it will not emit toxic smoke. This insulation is designed for indoor plenum spaces where air circulates freely such as dropped ceilings, raised floors, etc. 



Communications Multipurpose Riser (CMR) too is a high quality cable insulation that is designed to perform in extreme conditions. It is highly resistant to high temperatures and in case of a fire hazard, it prevents it from spreading. Ethernet cables with this insulation are to be installed in riser spaces such as elevator shafts, between floor, and within walls. 



PVC is the most affordable of all bulk ethernet cable insulations. It is reasonable enough to be used outdoors but it should not be used for indoor cable runs. For instance, this insulation is used in cables that connect outdoor IP cameras, ATMs, etc to a LAN network. 


Cable Shielding

Ethernet cable shielding is another type of cable insulation that is integrated underneath the cable jacket. Unlike the outer insulation, it can be made from a conductive metal or a non conductive plastic. 

The metal sheath is a foil that is wrapped around the conductors to absorb external noise in high cable density networks. And the non conductive insulation is wrapped around the individual pairs of ethernet cables that also prevent EMI and crosstalk.

Shielded cables are preferred for high performance networks due to their enhanced resistance against interference and better performance in large scale networks. However, for a small scale business network or a home network, unshielded cables are perfectly suitable because they are more affordable and get the job done seamlessly.


Which ethernet cable insulation do I need?

Now, all ethernet cable insulations have a specific design purpose and follow a definite safety standard. However you need to make sure that the cable you are getting is in compliance with the industry standards of safety. 

For instance, Cat6 plenum cable, as the name implies has a plenum jacket which is designed for a specific use that is in plenum spaces. But what’s important is making sure that it is in compliance with the safety standards of the industry. EIA/TIA are the foremost labels of performance and safety and if your cable has them, you are good to go. 

So, choosing bulk ethernet cables with the right jacket is easy. All you need to do is to know the specific use of the above mentioned types of insulation and make sure that it complies with the industry standards.