Is Oil Insulator? 7 Facts You Should Know!

Oil is a hydrophobic, lipophilic chemical substance composed of hydrocarbons and is flammable. This article deals with the study of the conductivity of oil.

Oil is an electric insulator but a good conductor of heat because there is no free electron constituting the oil that can freely mobile and conduct electricity. Thus there is no hindrance for the heat flux to pass through the oil and conducts heat across its volume. Hence, oil is inflammable when exposed to fire.

Due to oil’s electric insulation and thermal conductivity property, it is used in transformers. We shall further discuss the reason behind the electric insulation of oil and its thermal conductivity. We shall also ponder on the utilities of oil as an insulator and the electric conductivity of different types of oil.

Why is oil a good electric insulator?

Insulators are not capable of transmitting the electric flux through them. Let us discuss why oil is a good electric insulator.

Oil is a good electric insulator because it is a bad electric conductor and does not allow the electric flux to penetrate. Oil has high resistance and does not allow the electric current to flow. The bond between hydrogen and carbon is very strong; thus, oil behaves like a good electric insulator.

Is oil a thermal insulator?

Thermal insulators do not allow heat flux to pass through them by terminating the path. Let us discuss whether oil is a thermal insulator or not.

Oil is not a thermal insulator because the heat can easily pass through the oil matter and increase its temperature when heat energy is supplied. The thermal conductivity of oil is due to the absence of free electrons and strong bonding between hydrocarbons that allows the heat energy to pass through the oil.

Uses of oil as an insulator

Oil is used for various purposes in electric circuits due to its bad electric conductivity and good thermal conductivity. Let us list some uses of oil as an insulator.

  • Oil is used as insulation in the transformers on the windings of a coil.
  • Oil is used to prevent the ionization of the gas.
  • Oil is used in capacitors and circuit breakers.
  • Oil is used in fluorescent lamps and high-voltage switches.
  • Highly reactive metals are kept in oil to prevent exposure.
Image Credit: Oil by Biswarup Ganguly (CC BY 3.0)

Is kerosene oil an insulator?

Kerosene is composed of hydrocarbon molecules and is combustible oil. Let us discuss whether kerosene oil is an insulator or conductor.

Kerosene is an insulator because the strong hydrogen and carbon bonds do not break and allow the conduction of electric current flow. It can be conductive if it consists of some impurities that conduct electricity. Well, kerosene oil is a conductor of heat and thus is used as a lamp oil and fuel for combustion.

Is coconut oil an insulator?

Coconut oil is a solid fat white in colour when frozen, derived from the coconut palm fruit. Let us discuss whether coconut oil is an insulator or a conductor.

Coconut oil is an insulator in its pure form because it is composed of carbon, hydrogen, and oxygen atoms forming strong covalent bonds that are not easy to break. It is entirely made up of fats, is a good conductor of heat, and absorbs heat energy from the surrounding.

Is vegetable oil an insulator?

Vegetable oil is fatty oil extracted from vegetable plants’ seeds, fruits, and leaves. Let us discuss whether vegetable oil is an insulator or a conductor.

Vegetable oil is an insulator because it does not allow electric current to pass through it. It is also composed of strong hydrocarbon bonds and no free electron that does not allow the generation of electric current. It is biodegradable oil and finds its use in electrical industries due to its insulating property.


We can conclude with this article that oil is an electric insulator and thermal conductor as it is composed of strong hydrocarbon bonds that do not break easily but allow the heat to pass through the oil. Due to this behaviour, oil is used as an electric insulator.

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