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What Are the Different Types of Electrical Insulators?

Jordan Weagly
Jordan Weagly

An electrical insulator is a material that does not conduct electricity. Such materials can include ceramic, glass, non-ceramic, rubber and silicon dioxide. Different materials often have different purposes — to the extent that a particular material may be used exclusively in some electrical insulators and avoided in others. Electrical insulation often is used when voltage is low, as it is with most residential and commercial systems. Insulation prevents hazards associated with electricity, including short circuits and fires.

Ceramic insulators are often used in long-term electrical systems such as power lines. Clay and feldspar are some of the materials used to create ceramic electrical insulators. These kinds of insulators tend to work for many years and can maintain their shape and function despite hard conditions. Additionally, ceramics can form the often complex shapes required for effective insulation, which makes them useful for many specific applications.

A piece of feldspar, which is used to make ceramic electrical insulators.
A piece of feldspar, which is used to make ceramic electrical insulators.

Glass insulators are even more resistant to electrical and thermal forces, making them ideal for electrical applications such as incandescent light bulbs. Like ceramic insulators, glass insulators can hold their shape indefinitely, though impact may shatter them. Glass insulators are more difficult to shape without distortion or weakening, which limits their use.

Power lines often use ceramic insulators.
Power lines often use ceramic insulators.

Non-ceramic insulators can be made of a variety of materials, including plastic and complex alloys. The primary benefits of non-ceramic insulators are that they are less costly and a lighter weight than most other materials, and they can be used for long-distance electrical insulation. One disadvantage of non-ceramic insulators is that they might break down over time or as a result of severe weather conditions. This limits their use, especially in high-voltage systems. Regardless, many consumer electronics use non-ceramic insulation.

Electrical insulators work to prevent short circuits and sparks.
Electrical insulators work to prevent short circuits and sparks.

Rubber insulators are usually smaller than other types of electrical insulators and will often be used when other materials might be too fragile. Despite their size, rubber insulators are generally much more resistant to cracking and breaking. For instance, rubber insulators may be used instead of glass or ceramics in areas where more fragile insulators have a higher risk of shattering.

Silicon dioxide insulators can be miniaturized, which makes them ideal for electronics. Silicon dioxide insulators have helped with the creation of compact electronics in computers and mobile devices. Other materials used to create electrical insulators often do not work as well when combined with silicon-based electronic equipment. The material used to make these types of electrical insulators also can be used to help protect electronics from electrical interference when used as shielding.

Discussion Comments


@David09 - I think plastic is the best electrical insulator for many electronic gadgets. It’s cheap and can reshape quite easily. It may not withstand extreme heat or electrical conditions, but with portable electronics, that is rarely a concern.


@hamje32 - Ceramic is indeed useful. I read a story once that said NASA had developed a form of spray on ceramic paint, if you can imagine that.

The ceramic is in the form of a fine mist that is particularly resistant to heat (because it’s an insulator) and thus provides long lasting protection against the effects of extreme weather temperatures.

A lot of the heat is reflected back off the surface. In the end this reduces your utility bills, so I am sure the product pays for itself many times over.


Most people who think of electric insulation think of rubber material. At least I do. Rubber is really flexible and can be molded and adapted quite easily, to fit a variety of shapes and sizes for electrical wires. When I worked in electronics, almost all my components were insulated in rubber.

Personally I think it’s the best material for electrical insulation but this is not a professional opinion, just a result of my familiarity with its usage.

I didn’t know that other material, like ceramic, could be used. When I imagine ceramic I immediately think of something that is hard and brittle, as in a ceramic vase. I suppose there are malleable forms of ceramic out there that work well for power lines as the article points out.

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    • A piece of feldspar, which is used to make ceramic electrical insulators.
      By: Tyler Boyes
      A piece of feldspar, which is used to make ceramic electrical insulators.
    • Power lines often use ceramic insulators.
      By: ComZeal
      Power lines often use ceramic insulators.
    • Electrical insulators work to prevent short circuits and sparks.
      By: Steven Love
      Electrical insulators work to prevent short circuits and sparks.