Different Types of Cable Insulators

Cable Insulators

Electrical Cable can come with insulation or not. There is some type of overhead transmission and distribution cable don’t have insulation on it because it stays up from ground level. But if a cable is passing through the ground level and humans and animals are crossing nearby then there is a big possibility that anyone can get Electrical Shock if the cable is not having insulation.

Like cable insulation, a cable insulator is also important equipment in power transmission and distributions system. It keeps safe our transmission and distributions line when the line is active. Cable insulator present between tower to tower. In this post, we will learn Different Types of Cable Insulators.

What is Cable Insulators:

An insulator is one kind of material that prevents the flow of electric current and can be used to support the electrical conductor. The main function of an insulator is to separate the line conductors from the pole and the tower. Normally the conductor of overhead transmission and distribution line is secured by means of the insulator.

It used to prevent the leakage current to the earth through the pole. Jumper safe the line by overloaded. The insulator plays an important role in a successful transmission & distribution for the electrical line. Now the materials most commonly used for an insulator for overhead lines are,

  1. Porcelain
  2. Glass
  3. Steatite
  4. Synthetic


Porcelain is an extensively used material & it produced by firing at very control temperature by a mixture of kaolin, feldspar, and quartz. It is mechanically stronger than the glass. The porcelain surface is not affected by any kind of dirt deposits and it is less susceptible to changes in temperature.

Porcelain insulator has much dielectric strength and its about 60KV/cm of its thickness. The compressive strength of good porcelain is about 70000 Kg/ cm2 and tensile strength is about 500kg/cm2.

Related: Aluminium Conductor Steel Rein-Forced (ACSR)


The glass is a little bit cheaper than porcelain in the simple shapes and if property toughens and the follow annealed gives resistivity and very high dielectric strength. Glass is quite a homogeneous material and very high compressive stress. It’s a very lower coefficient of thermal expansion.

Owing to its transparent nature it can be readily by visual inspection. The main disadvantage of glass is that moisture is easily condensed on its surface.


Steatite is naturally occurring magnesium silicate and is usually found combined with oxides in varying proportions. Steatite has higher tensile and bending stress than porcelain and glass. It can easily be used between tension towers or when the transmission line takes very sharp turns.


Synthetic is non-ceramic insulators and it consists of a fiberglass rod covered by weather shed or skirts of the polymer.

Related: Various Types of Electrical Cable Conductor

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  • Cable Insulators
    Electrical Cables

    Different Types of Cable Insulators

    Electrical Cable can come with insulation or not. There is some type of overhead transmission and distribution cable don’t have insulation ...
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