Ground conductor

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A ground conductor (also known as an earth conductor) is an electrically conductive wire or cable on the top of pylons. The ground conductor is designed protect the power conductors from lightning strikes.

Most ground conductors are able to earth electrical strikes via the body of the pylons but in some cases where earthing conditions are poor, specially designed earthing cables are used.

As a general rule, power lines with voltages below 50 kV do not have a ground conductor, but most lines carrying more than 50kV do. This is largely determined by the effectiveness of automatic circuit breakers which are able to protect low voltage installations but which are less efficient at higher voltages because of the persistence of arcing and the distances that need to be travelled by moving parts in a circuit breaker before the circuit is effectively broken.

If there are more demanding requirements for lightning protection, two ground conductors, one on each of the edges of the pylons may be used. In such cases the pylons are either equipped with an additional crossbeam above the conductors, with two tops in form of a letter "V" or the ground conductors are mounted on the top of the topmost crossbeam.

In some parts of the world, the ground conductor cable is used to support fibreoptic cables for data transmission such as on some powerlines in Germany which were built before 1985 by the former EVS AG (nowadays EnBW AG) in Baden-Württemberg.de:Erdseil