Different Types of Insulators and Their Applications

What is an insulator?

An insulator is a substance where electricity does not flow freely. This is due to the insulator’s atoms’ more tightly bonded electrons, which are immobile. Air, glass, plastic, paper, and rubber are all common insulators.

Due to their greater ability to carry electric current, semiconductors and conductors are non-insulator materials. Insulators have greater resistivity than semiconductors or conductors. They are mostly employed to cover electrically conducting materials.

For instance, the cables’ plastic sheathing prevents power from running where it is not needed. Insulators are further employed especially to join electricity transmission or distribution wires to utility poles and transmission towers.

The insulator is used to stop electricity from flowing towards the earth and leaking from the overhead line. The insulator is put overhead rather than at the end. The transmission line’s overhead plays a crucial role. A wide range of materials, including rubber, wood, plastic, and mica, can be used to create insulators.

Glass, ceramic, steatite, PVC, and polymer are the primary materials utilised to provide insulators for electrical systems. However, porcelain is the most typical material utilised in the production of insulators.

Why are insulators necessary?

Separating the conductor from the transmission tower in the transmission line is the insulator’s main purpose. They provide a barrier between the electrical circuit’s active components and, when necessary, limit the current’s ability to pass through wires or other conducting channels.

When an electron travels in a wire, an electric current happens. Since the electrons in insulators are strongly bonded, they remain immobile within the material. In order to prevent current from leaking to earth, they keep the current in place and isolate the conductor from the pole.

Current will flow over the pole if it is improperly insulated. Therefore, when an animal or person touches the pole, they are shocked, which can also lead to death.

Insulating qualities

Insulators vary from other electrical devices due to a number of unique characteristics. Here are a few characteristics of insulators:

  • High resistivity
  • strong properties for the conductor load
  • Relative permittivity of insulator materials is high.
  • strong dielectric properties
  • Non-porous or waterproof

Insulator material types

Different types of insulator materials, such as plastic, rubber, mica, wood, and glass, are used to make insulators. Specific insulating materials, such as porcelain, glass, steatite, polymer, ceramic, and PVC, are employed in the electrical system.

List the Different Types of Insulators

A substance whose internal electric charges do not flow freely is an electrical insulator. The right insulation choice has a significant impact on how successfully an overhead line operates. The five different kinds of insulators are:

  1. Pin Insulator
  2. Suspension Insulator
  3. Strain Insulator
  4. Stay Insulator
  5. Shackle Insulator
  6. Disc insulators
  7. Post insulators
  8. Polymer insulators
  9. Glass insulators
  10. Long rod insulators

Pin Insulator

Although pin insulators were the first overhead insulators to be created, they are still often employed in power networks up to 33 kV systems. Depending on the application voltage, pin type insulators might be one part, two part, or three part types.

In an 11 kV system, one component type insulators are typically used, where the entire pin insulator is made of a single piece of appropriately formed glass or porcelain.

Since an insulator’s leakage channel runs over its surface, it is preferable to increase the vertical length of the insulator’s surface area. To achieve a lengthy leakage route, we offer one, two, or more rain sheds or petticoats on the insulator body.


The post-insulator offers a lot of strength while having the appearance of a pin-type insulator. The substation uses this insulator far too frequently since it is ideal for a variety of voltage levels. Transformators, switchgear, and other connecting equipment are protected by these insulators because of their vertical placement.

Due to the fact that there are more petticoats in the post insulator than in the pin insulator, this is taller than the pin insulator. The material utilised to create this insulator is porcelain.

Glass Insulators

These particular insulators, which are often composed of toughened or annealed glass, are utilised in power transmission lines. This insulator’s function is to insulate the wires so that electricity won’t seep into the earth or into any of the poles.

Before ceramic and porcelain kinds were introduced in the 19th century, telegraph and telephone lines initially employed glass insulators. Toughened glass varieties were produced to address the weakness of glass and gained popularity because of their long lifespan.

Suspension Insulator

Beyond 33KV, increasing voltage makes using pin insulators uneconomical due to the insulator’s increased bulk and weight. Larger single unit insulators are challenging to handle and replace. Suspension insulators were created as a solution to these problems.

In suspension insulation, a string of insulators is formed by joining them in series, with the lowest insulator carrying the line conductor. Due to its disc-like form, each suspension string insulator is known as a disc insulator.

Shackle Insulator

Small in size, these insulators are utilised in overhead distribution systems. This insulator can be connected by means of a metallic strip. This insulator has a 33 kV voltage capacity and may be used in bend or circular turn locations. These insulators are now utilised as strain insulators, although less voltage distribution lines use them. Insulators for shackles can be positioned either vertically or horizontally. These have a bolt or cross arm connecting them to the pole. 

Long Rod Insulators

In order to isolate the transmission lines, the long rod insulators are often hinged on steel towers. They also serve as protective mechanisms by securely supplying electricity. Long rod insulators often consist of many insulators depending on the usage and demand.

These are porcelain rods with metal end fittings and a weather shelter on the outside. Employing this kind of insulator has the benefit that it may be used in tension and suspension positions.

Disc Insulators

The insulator is referred to as a disc insulator because, as its name implies, it resembles a disc. High voltage transmission and distribution lines employ this kind of insulator. To achieve the needed electro- strength, disc insulators are created.

They also offer an economical solution for moderately and lightly polluted areas. Transmission lines, industry, and commerce all use these insulators because of their high efficiency qualities like reduced corrosion and sturdy construction.

In suspension and tension systems, they support and insulate line conductors. Additionally, it has the ability to sustain high voltages under heavy loads.

Strain insulators

These insulators are designed to withstand the stretching caused by a cable or wire that is suspended and is under stress. Similar to a suspension insulator, it supports radio antennas and overhead power cables.

A strain insulator is placed in between two lengths of wire to maintain the connection while electrically disconnecting them. When a wire connects a pole or tower, it may also be used to convey the draw of the wire to the support while electrically insulating it. These insulators have a voltage potential of about 33 kV.

Stay Insulator

This particular low voltage insulator combines a stay wire or main grip to counterbalance and secure dead-end poles. These insulators have a rectangular form and come in smaller sizes than those of other varieties.

These insulators can be positioned between the ground and the line conductor. Additionally, they serve as safeguards against unexpected voltage fluctuations or malfunctions that occur suddenly. When the poles collapse to the ground or when the stay wires unexpectedly snap from an increased stress, the significance of these insulators is evident.

Polymer Insulators

These are a kind of electrical devices that are frequently constructed of polymer materials and metal fixtures. Additionally, these insulators are encircled by polymer weather shelters and are constructed of fibreglass rods. The insulator core is protected from the outside environment by weather shades.

Insulators made of polymer are more powerful than those made of porcelain while being less in weight. It is typically regarded as being an excellent insulator of heat and electricity. Due of its distinct electrical, mechanical, chemical, and thermal characteristics, it is utilised as an insulator.

Applications of Insulators
The programmes are

  • To ensure safety procedures, they are employed in circuits and electric boards.
  • These insulators shield the materials from heat and electricity.
  • Daily items are made from plastic and rubber.
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