General rules of lightning protection

Procedure to prevent risks of lightning strike

The system for protecting a building against the effects of lightning must include:

• protection of structures against direct lightning strokes;
• protection of electrical installations against direct and indirect lightning strokes.

The basic principle for protection of an installation against the risk of lightning strikes is to prevent the disturbing energy from reaching sensitive equipment. To achieve this, it is necessary to:

• capture the lightning current and channel it to earth via the most direct path (avoiding the vicinity of sensitive equipment);
• perform equipotential bonding of the installation;

This equipotential bonding is implemented by bonding conductors, supplemented by Surge Protection Devices (SPDs) or spark gaps (e.g., antenna mast spark gap).

• minimize induced and indirect effects by installing SPDs and/or filters.

Two protection systems are used to eliminate or limit overvoltages: they are known as the building protection system (for the outside of buildings) and the electrical installation protection system (for the inside of buildings).