4.5 Separation distances

Separation distances serve to prevent dangerous sparkovers between lightning-current-carrying components of the external lightning protection system (air-termination systems, down conductors) and electrically conductive parts inside the building. Compliance with these distances is crucial for the safety of people and technical equipment.
In the event of a direct lightning strike, a high current flows through the external lightning protection system. In close proximity to other conductive systems (e. g. pipelines, cable routes, metal façade elements), flashovers may occur if the distance is too short. This can:

• cause sparking and fires.
• pose danger to people due to touch voltages.
• cause faults to or the destruction of technical systems.