7.1 Tasks

The internal lightning protection system has the task of protecting people, buildings and technical equipment from the consequences of a lightning strike by preventing dangerous overvoltages and potential differences inside a structure. When lightning strikes, high lightning impulse currents flow and voltages arise which, without protective measures, could cause fires or endanger people. The use of surge protective devices reduces voltage spikes caused by direct strikes or electromagnetic coupling to a safe level and diverts them to earth in a targeted manner. At the same time, the equipotential bonding ensures that all conductive parts such as water and heating pipes, electrical cables or metal structures are connected to each other so that no dangerous voltage differences can occur that would lead to sparkovers. Another important measure is maintaining the separation distance, i.e. a defined minimum distance between the lightning-current-carrying parts of the external lightning protection system and the metallic or electrical installations inside the building. This distance prevents the lightning current from jumping uncontrollably to internal wiring and causing damage there. Where the distance cannot be maintained for structural reasons, insulated down conductors or additional insulating materials are used. This also protects sensitive electronics such as computers, routers or control systems, which could be destroyed even by minor power surges. The internal lightning protection system thus complements the external lightning protection system, which safely dissipates the lightning current into the ground, ensuring that the energy from the lightning does not enter the building. Only the interaction of both systems ensures comprehensive protection for people, buildings and technology.