Utility pole

A utility pole is a column or post usually made out of wood used to support overhead power lines and various other public utilities, such as electrical cable, fiber optic cable, and related equipment such as transformers and street lights. It can be referred to as a transmission pole, telephone pole, telecommunication pole, power pole, hydro pole, telegraph pole, or telegraph post, depending on its application. A Stobie pole is a multi-purpose pole made of two steel joists held apart by a slab of concrete in the middle, generally found in South Australia. Electrical wires and cables are routed overhead on utility poles as an inexpensive way to keep them insulated from the ground and out of the way of people and vehicles. Utility poles can be made of wood, metal, concrete, or composites like fiberglass. They are used for two different types of power lines: sub transmission lines, which carry higher voltage power between substations, and distribution lines, which distribute lower voltage power to customers. The first poles were used in 1843 by telegraph pioneer William Fothergill Cooke, who used them on a line along the Great Western Railway. Utility poles were first used in the mid-19th century in America with telegraph systems, starting with Samuel Morse, who attempted to bury a line between Baltimore and Washington, D.C., but moved it above ground when this system proved faulty. Today, underground distribution lines are increasingly used as an alternative to utility poles in residential neighborhoods, due to poles' perceived ugliness, as well as safety concerns in areas with large amounts of snow or ice build up. Utility poles are commonly used to carry two types of electric power lines: distribution lines (or "feeders") and sub transmission lines. Distribution lines carry power from local substations to customers. They generally carry voltages from 4.6 to 33 kilovolts (kV) for distances up to , and include transformers to step the voltage down from the primary voltage to the lower secondary voltage used by the customer.