The ETITEC C is surge arrester intended for indoor applications. The C 255/20 G is an overvoltage arrester with a gas discharge tube for protection against indirect lightning strikes, and it is used as a galvanic separation between N-PE conductor in TT network systems. Features an indication window for when the device develops a fault, has remote signalisation, and mounting on top hat fixing DIN rail. The Group C surge protection is in accordance with VDE class C, and this protection corresponds to IEC category II. The protection is made on the subdistribution box, as the second level of protection against overvoltage indirect lightning strikes. In case of permanent arrestor damage, the thermal protection is activated which indicates a faulty arrester. Please note that the first number of designation 1+0, 2+0, 3+1 etc. indicates the number of varistors. The second one indicates the following- number 0 indicates there is no gas discharge tube, number 1 indicates there is.