Front-mount auxiliary switch for SIRIUS contactors
The Siemens 3RH2911-1HA20-ZW97 is a front-mounted auxiliary switch block carrying 2 normally-open contacts, designed for the SIRIUS 3RT2 contactor and 3RH2 contactor relay family. It snaps onto the front of the device without tools, adding two NO signal paths for status feedback or interlocking in the control panel. Rated for a maximum of 10 A, the switch handles control-circuit loads across a wide voltage range: 6 A at 24 V, 6 A at 125 V, 6 A at 230 V, and 3 A at 400 V. The AC-15 rating at 690 V is 1 A, covering the typical pilot-duty switching in motor control centers. Mechanical service life is rated at 10 million switching cycles typical, with contact reliability of 1 faulty switching per 100 million operations at 17 V, 1 mA. That makes it suitable for high-cycling applications like conveyor interlock chains or valve position feedback where missed signals cause nuisance downtime.
Snap-on integration and wiring
Mounting is snap-on — no screws or DIN-rail adapter needed. The block clips directly onto the front of the base contactor or relay, occupying 36 mm width and 43.7 mm depth, with a height of 37.5 mm. Panel builders can plan the fill factor knowing each auxiliary block adds roughly the same footprint as the base device's front face. Wiring uses screw-type terminals accepting 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) with core end processing, or 2x (20 to 16) and 2x (18 to 14) AWG. The IP20 protection on the front means the terminals are finger-safe once installed inside an enclosure — standard for control-panel auxiliary contacts.