Guard cables
Overhead lines: equipment.

The multiple roles of ground wires, their sizing and layout on lines are described in article [D 4 421] (§ 2.3.1). Remember that they must satisfy both mechanical and electrical requirements.

Located above the conductors, they are tighter than the latter to ensure good protection against lightning. However, despite their small cross-sectional area, they must offer the same mechanical safety as the conductors in the event of strong winds or an overload of frost or snow. It is therefore imperative that they be calculated using the same climatic assumptions as the conductors, and that the forces they generate in the supports...