Lightning Protection Zone (LPZ) — Classification per IEC 62305-4

A zoning system (NEN-EN-IEC 62305-4) that divides a building and the electrical and electronic systems within it into zones with progressively decreasing levels of lightning-induced effects, so that the correct surge protective device (SPD) can be determined at every zone boundary. LPZ 0A is the area outside the building with a risk of a direct lightning strike and exposure to the full electromagnetic field; LPZ 0B also lies outside the direct zone of influence of conductors but without risk of a direct strike thanks to the air-termination system; LPZ 1 is the area inside the building where the lightning current carried by wiring has already been limited by a type 1/2 SPD at the main distribution board and the electromagnetic field has been attenuated by the building envelope; further zones (LPZ 2, 3, …) lie deeper inside the building, for example in a shielded server room, with progressively further reduced current and field levels. At every boundary between two zones an SPD with a test class matched to that boundary must be installed to progressively catch the remaining energy.