Lightning protection - Electrical installation protection system

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The main objective of the electrical installation protection system is to limit overvoltages to values that are acceptable for the equipment.

The electrical installation protection system consists of:

  • one or more SPDs depending on the building configuration;
  • the equipotential bonding: metallic mesh of exposed conductive parts.


The procedure to protect the electrical and electronic systems of a building is as follows.

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  • Identify all sensitive loads and their location in the building.
  • Identify the electrical and electronic systems and their respective points of entry into the building.
  • Check whether a lightning protection system is present on the building or in the vicinity.
  • Become acquainted with the regulations applicable to the building's location.
  • Assess the risk of lightning strike according to the geographic location, type of power supply, lightning strike density, etc.

Solution implementation

  • Install bonding conductors on frames by a mesh.
  • Install a SPD in the LV incoming switchboard.
  • Install an additional SPD in each subdistribution board located in the vicinity of sensitive equipment (see Fig. J16).
Fig. J16 – Example of protection of a large-scale electrical installation