Transmission lines carrying voltages of above 230 kV are usually not supported by poles, but by metal pylons (known as transmission towers in the US).įor economic or practical reasons, such as to save space in urban areas, a distribution line is often carried on the same poles as a sub transmission line but mounted under the higher voltage lines a practice called "underbuild". 230 kV lines are often supported on H-shaped towers made with two or three poles. They usually carry 46 kV, 69 kV, or 115 kV for distances up to 60 miles. Subtransmission lines carry higher voltage power from regional substations to local substations. A service drop carries this lower voltage to the customer's premises. They generally carry voltages from 4.6 to 33 kilovolts (kV) for distances up to 30 miles, and include transformers to step the voltage down from the primary voltage to the lower secondary voltage used by the customer. Distribution lines carry power from local substations to customers. Utility poles are commonly used to carry two types of electric power lines: distribution lines (or "feeders") and sub transmission lines. In central Europe, lines usually run just straight across fields, rows of poles accompanying roads are quite rare. (video) Three aerial work platform trucks work together on utility poles, in Bunkyō, Japan Use Wooden electricity poles in Germany. 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 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. The first poles were used in 1843 by telegraph pioneer William Fothergill Cooke, who used them on a line along the Great Western Railway. 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. Utility poles can be made of wood, metal, concrete, or composites like fiberglass. 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.Įlectrical 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. 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 pair of shoes can be seen hanging from the wires (center-left, far right)Ī 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. Post used by public utilities to support overhead wires and related equipment Utility pole supporting wires for electrical power distribution, coaxial cable for cable television, and telephone cable.
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