FI/LS switch, Icn: 10 kA, 2P, Type A, 30 mA, B-Char, In: 20 A, Un AC: 110 V. FI/LS for combined short circuit protection and touch protection. The patented FI/LS switches from Siemens are an essential component of the SENTRON protection devices for electrical installations, enabling combined personal, fire, and line protection in a single device. In addition to detecting fault currents, they also provide reliable protection against short circuits and overloads thanks to the integrated overcurrent protection device. The Siemens FI/LS switches, as a combination of residual current and circuit breakers, are particularly characterized by: 1. Increased operational safety and system availability due to the separate disconnection of the affected circuit. 2. Whether sinusoidal alternating fault currents or smooth direct fault currents - Siemens offers the right type for all requirements, as well as special versions. 3. Reliable safety during installation thanks to standard included gripping and touch protection.