Electrical Insulator must be used in electrical system to prevent unwanted flow of current to the earth from its supporting points. The insulator plays a vital role in electrical system. Electrical Insulator is a very high resistive path through which practically no current can flow. Electrical insulators are different from electrical conductors. Electrical conductors are those materials which propagate the ease of flow of electricity throughout them. They allow charges to flow easily through them. Insulators, on the other hand, are materials that do not allow electric charges to flow freely through them.
Conductors have a property called conductivity which defines their ability to conduct electricity. For insulators, their effectiveness is determined based on how much resistance they offer to the flow of electricity. This property, in contrast to conductivity, is called resistivity. Plastic, Rubber, Wax, Wood, Glass, Air and Styrofoam etc, are the examples of Insulator.
Most non-metals are poor conductors and therefore good insulators. They do not have free electrons available to conduct electricity. Materials with larger resistivity values, offer greater resistance to the flow of electric current and are therefore better insulators. For example, glass has a resistivity value of (ohm metre), and copper has a value of resistivity of.
Properties that affect the effectiveness of an insulator:
- High resistivity as we have already discussed
- Breakdown voltage
- Atomic structure
- Air permeability
Insulators are mainly used in applications where the prevention of flow of electric charges is required. These materials work as effective non – conductors. Since they lack movable electric charges required to propagate electric current. Electrical insulators are used mainly as parts in electrical equipment. For example, the electrical wires which transfer electricity through households are covered with insulation material to prevent any safety hazards. The electrical plugs have an insulated covering to prevent electricity flowing from the metal socket to your body by stopping the flow of electrons.