Insulator (electricity) - Telegraph and Power Transmission Insulators

Telegraph and Power Transmission Insulators

Suspended wires for electric power transmission are bare, except where they enter buildings, and are insulated by the surrounding air. Insulating supports called insulators are required at the points at which they are supported by utility poles or transmission towers. Insulators are also required where the wire enters buildings or electrical devices, such as transformers or circuit breakers, to insulate the wire from the case. These hollow insulators with a conductor inside them are called bushings.