Plastics are solid materials made from oil. There is a huge number of different plastics. Each one has been made with special useful properties. All plastics are insulators.

Although plastics have many different properties they all have one thing in common. Plastics do not conduct electricity. They are insulators. Flexible plastics are used to coat wires and to make cables. The cables may be thin, such as those used to connect a mouse to a computer keyboard, or thick, such as those used to bring electricity into the house.

The plastic keeps electricity in the wire and does not allow it to pass to anyone who touches the cable. Hard inflexible plastics are used to make switches, plugs and sockets. These provide strong, insulating covers.