8.1 Scope

This chapter considers the geometry of conductors and the various materials used. This is followed by a look at the electrical requirements, how to calculate them and a look at the current ratings and greasing (corrosion) requirements of bare and covered conductors. The covering can be simply a thin sheath or full insulation. In the former, the conductor is covered to reduce clashing problems or for safety or space reasons but it is not insulated. It must be remembered, however, that the best choice electrically may not be the best choice mechanically or even environmentally.

Conductor selection is a complex business. It is dependent not only on electrical, magnetic and economic considerations, but also on radio interference, stray fields and fault level capability. Mechanically, the conductor must support its own weight as well as any ice and wind loading, and must maintain ground clearances under all predicted environmental conditions.

It is hoped that this chapter will familiarise the reader with the characteristics of a range of commonly used conductors and list the criteria for conductor selection for a particular job. As an aide for information, a section is included giving a brief history of the development of covered conductors.