According to the requirements and loads placed on surge protective devices, they are categorised as lightning current arresters, surge arresters and combined arresters.
The highest requirements are placed on the discharge capacity of lightning current arresters and combined arresters used at the transition from lightning protection zone 0A to 1 or 0A to 2. These arresters must be capable of conducting partial lightning currents of 10/350 μs wave form without being destroyed in order to prevent the ingress of destructive partial lightning currents into the electrical installation of a building.
At the transition point from LPZ 0B to 1 or downstream of the lightning current arrester at the transition point from LPZ 1 to 2 and higher, surge arresters are used to protect against surges. Their task is both to reduce the residual energy of the upstream protection stages even further and to limit the surges induced or generated in the installation itself.