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Electric Power Conductor Insulation Types

To protect delicate electronic equipment from the dangers of fire and shorting out, and to protect those who use the equipment, many conductors of electricity are wrapped in insulation. There are many different materials used as insulation. Which material you select for your electronic or electrical projects depends on the particular current you plan to use, how much metal is exposed, how fast heat builds up and other considerations.

Electric Conduction and Insulation
- All materials are made out of atoms. Atoms, in turn, are made of negatively charged electrons orbiting around positively charged nuclei. When an electrical voltage pushes on electrons in a circuit or device, it crowds them closely together. Because like electrical charges repel and unlike charges attract, this causes some of the crowded electrons to jump out of the atoms they are a part of and become attracted to the nuclei in other atoms. This flow of electrons is electricity. Conductors are materials that hold onto their electrons loosely, allowing them to move easily. Insulators hold onto their electrons tightly, preventing them from moving easily.
The Best Insulators
- The most effective insulator is quartz, with a resistivity of 50 quadrillion ohm-meters. Mica is next most effective, with a resistivity of 90 trillion ohm-meters. Glass is third, with a resistivity of one trillion ohm-meters. In comparison, copper, a common electrical conductor, has a resistivity of less than one one-hundred-millionth of an ohm-meter.
Other Insulators
- Plastic, rubber, paper, ceramic and wood are all effective insulators too, though they rank below quartz, mica and glass. Enamel, cotton, special oils and inert gasses are also used as insulators. Chemicals like flourinated ethylene propylene are sometimes used as well.
Examples
- Wires are often insulated with thermoplastic, which is a special type of plastic that can withstand high heats. Some wires are insulated with enamel. The enamel is much thinner than plastic and makes the wires suitable for making solenoids, electromagnets and any other device that needs to put a large amount of wire into a small space. High voltage lines use glass, porcelain or special polymers for insulation. Large underground power conductors are insulated with paper and high-pressure nitrogen or oil. High-voltage transformers use special high-resistivity oils for their insulation. The tiny circuits of computers use thin layers of oxides as insulators.

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