How Do Electrical Insulators Work and What Are Their Types?

In our current day, much of our daily activities and livelihoods depend on electricity and electric technology. While many of these components are very beneficial to us, the electricity that powers them can be very volatile and dangerous. As electricity can damage components and harm people, it is important to implement protection to ensure that such occurrences can be avoided or prevented altogether. With insulating material, such protection can be achieved and is widely used across all types of electronics and components that interact with electricity.

What is Electrical Insulator ?

In general, an electrical insulator is a material that is implemented within an electrical system in order to provide high electrical resistance, impeding any current from flowing through it. Typically, various types of insulating material will be similar in the fact that they have low amounts of electrons that are free, thus they have low chance of carrying electrical current. As no material is entirely devoid of electrons, even the best insulating material will allow some leakage of current. Nevertheless, these amounts of leakage are often negligible enough to not warrant an issue or a concern for the system or those who interact with them.

It is important to ensure that the amount of current that is present within a system does not exceed the level of electrical resistance that is provided by the insulator. If enough current is inducted, the insulator will actually become conductive itself. When this occurs, it is referred to as insulation breakdown, and the voltage that leaks through is called breakdown voltage. To avoid this occurrence, it is always highly recommended to utilize types of insulating material that provides high resistivity and high dielectric strength. Additionally, the application in which the insulating material is being used should be considered, as different materials may provide for various properties that each have their own benefits. For example, when constructing cables and wires, the insulating material should be very flexible such as PVC or rubber. Meanwhile, an overhead power line will require something much more robust and strong, such as porcelain or glass insulators.

Properties of Electrical Insulator :-

When choosing between insulators, there are some important properties of insulating materials that should be considered, namely resistivity, dielectric strength, dielectric constant, and dielectric loss. The resistivity of a specific insulating material should be one of the first things considered when choosing between various types of insulating material. Resistivity in general refers to how capable a particular component is at mitigating the flow of electric current. Usually, the higher the resistivity factor, the better of an insulator the material will be.

Working of Electrical Insulators :- 

The dielectric strength is the maximum electric field that a specific material can endure before resulting in an insulation breakdown. When shopping for insulators, the dielectric strength is typically denoted by a value in kilovolts per millimeter, or kV/mm. Factors that typically affect the dielectric strength of a particular material include thickness, operating temperature, and frequency.

Dielectric constant, otherwise known as relative permittivity, concerns the electric flux density production ratio of a specific material to that of the production within a vacuum. Relative permittivity is the ratio of the electric field between charges decreasing in relation to the vacuum. When referencing the dielectric constant of an insulating material, the value is referred to with εr(ω), or less commonly as κ.

Dielectric loss, also known as the electrical dissipation factor, refers to the ratio of lost power within the material as compared to the full amount of power that is passed through it. Dielectric loss is denoted by DF or tan δ, and also may be called the tangent of the loss angle, loss tangent, tan delta, and so on. Put simply, the dielectric loss of an insulating material is how efficient it is at behaving as an insulator. When energy is absorbed by types of insulating material, the energy is dissipated as heat.

Depending on the application in question, there are many types of electrical insulators that are available.

Types of Electrical Insulator :- 

  1. glass insulator
  2. pin insulator
  3. shackle insulator
  4. strain insulator

Glass Insulator :- 

Glass insulators were very commonly used during the 18th century, typically serving telegraph and telephone lines. Despite being superseded by ceramics and porcelain, toughened glass insulators are still desired for many applications due to not aging, allowing for a much longer lifespan as compared to ceramics. Glass insulator discs may also be used for a suspension insulator.

Pin Insulator :- 

Pin insulators are insulators that isolate a wire from the physical support of the system. More often than not, pin insulators are used for telegraph and utility poles, and ceramic pin-type insulators are still used for many power lines. As compared to other types of insulators, the pin insulator is directly connected to the support and allows for securely attaching the wire.

Shacle Insulator :- 

Shackle insulators, also referred to as spool insulators, are those that are used in various low voltage systems. The shackle insulator features a tapered hole which helps the load of the system be distributed more evenly so that the chance of an insulation breakdown is decreased. Currently, many shackle insulators have been replaced with underground cabling systems.

Strain Insulator :- 

Strain insulators are those that utilize suspension string to aid in the sustaining of high tensile loads. To undertake such requirements, strain insulators are designed to have exceptional mechanical strength, as well as high amounts of insulation capability. Typically, strain insulators are used to support radio antennas and overhead power lines.

When it comes time to begin sourcing the various types of insulating material that you need for your next project or operation, ASAP Buying has you covered with everything you are searching for. ASAP Buying is owned and operated by ASAP Semiconductor, and we can help you find the aircraft, marine, and IT parts that you are searching for, new or obsolete. As a premier supplier of parts for the aerospace, civil aviation, and defense industries, we're always available and ready to help you find all the parts and equipment you need, 24/7x365. ASAP Semiconductor is an AS9120B, ISO 9001:2015, and FAA AC 0056B Accredited enterprise. For a quick and competitive quote, email us at or call us at +1-714-705-4780.


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