FI/LS for combined short-circuit protection and touch protection. The patented RCDs from Siemens are an important component of the Sentron protection devices for electrical installations and enable combined personal, fire and line protection in just one device. In addition to detecting residual currents, they also offer reliable protection against short circuits and overloads thanks to the integrated overcurrent protection device. As a combination of residual current circuit-breaker and miniature circuit-breaker, the Siemens RCDs are characterised above all by: 1. increased operational safety and system availability thanks to separate disconnection of the affected circuit. 2. whether sinusoidal AC residual currents or smooth DC residual currents - Siemens offers the right type and special versions for all requirements. 3. reliable safety during installation thanks to the standardised gripping and contact protection. 4. tool-free detachment from the top-hat rail.