Weidmuller VPU I (Type I), VPU II (Type II) and VPU III (Type Ill) surge protection products effectively reduce the interference coupling that can occur due to transient surge voltages, even significantly below the limits prescribed by insulation co-ordination according to EN 60664-3 / DIN VDE 0110-3. This means that the whole installation is exposed to fewer malfunctions. The arresters are co-ordinated using technical means. This means that decoupling between Types I, Il and Ill is unnecessary. The arresters are tested according to product standard IEC 61643-11 / DIN EN 61643-11 and can be installed in systems according to IEC 6 1643-12 / VDE 0675-6-12 and IEC 62305-4/VDE 0185-4. This lightning and surge protection device is suited for installation in power supply systems. Weidmuller offers different products depending on the particular mains network type and voltage level. A special Type I and Type ll protective device is even available for photovoltaic applications.