Fault signal contact with test and acknowledgment key 2 NO for miniature circuit breaker 5SL, 5SY, 5SP RCBO 5SU1, FI 5SV (for 5SU1 handle coupler 5ST3805-1 is required) Additional components for residual current protective devices and miniature circuit breakers from Siemens. The additional components from Siemens are an important part of the SENTRON protection devices for electrical installations. As accessories for residual current and miniature circuit breakers, they offer many options for implementing a wide range of functions. Whether for infrastructure or industrial applications, Siemens offers the right accessories for all residual current and miniature circuit breakers. We provide the right device for every requirement. Key features of the Siemens accessories for residual current and miniature circuit breakers: 1. Can be universally retrofitted with all additional components 2. User-friendly and easy installation and connection technology. 3. Reliable safety during installation with standard touch protection. 4. Optimized technology for your safety – only from Siemens.