Class C (II) varistor surge arrester -BY1-C/4 3221040

Modular, varistor surge arresters for protection of LV power supply installations in small buildings, single-family houses, apartments and other compact buildings. They provide sufficient protection both against the effects of overvoltages caused by lightning, as well as induced or switching overvoltages. Mounted in a cable connector or main switchgear. For TT and IT networks, a combination of BY1-B/3 arrester and NPE spark gap is used. The control windows indicate the state of correct operation (green color) and the state of varistor damage (red color). In the event of damage to the varistor, the arrester insert must be replaced immediately. Arresters equipped with an acoustic-contact fault signaling module and a signaling contact are also available. Varistor limiters must be systematically inspected (after each storm as well as after the end of the storm season).