PZH R3* S is a two-stage surge arrester. A high-frequency filter is integrated between these two stages. The PZH R3* S includes an upgraded thermal fuse which ensures the timely disconnection of the PZH R3* S from the mains supply when the varistor overheats and prevents the PZH R3* S from any damage. The activation of the thermal fuse is signalled by an integrated light indication with the possibility of using the switch contact for remote monitoring (S) to signal the fault. By using a new design of the thermal fuse, the protective voltage level is 100 V lower than the previous series of filters produced. PZH R3* S is a two-port surge arrester type T3 tested according to the standard EN 61643-11 ed.2 (IEC 61643-11: 2011). According to EN 62305 ed.2 (IEC 62305: 2010) it is to be installed at the interface of LPZ 2 - LPZ 3 zones where it limits the induced overvoltage and residual overvoltage in power lines. PZH R3* S is installed on a 35 mm DIN rail with a metal clip. Manufacturer’s recommendation: PZH R3* S is to be installed as close as possible to the protected device (max. 5 m). In front of PZH R3* S must be installed a lightning arrester T1 and surge arrester T2 from Hermi.