Siemens 5SX9100 is an auxiliary contact switch for Siemens miniature circuit-breakers, providing a mountable 1 normally open and 1 normally closed (1 NO + 1 NC) contact set. It is designed as an accessory for the 5SX2–5 family, enabling simple status signaling and interlock logic in control circuits without altering the main breaker. Siemens lists the 5SX9100 as a no longer available product, with the 5ST3010 documented as its successor for compatible installations. This accessory supports remote signaling and monitoring in low‑voltage panels by feeding discrete feedback signals from the breaker assembly.
