The Siemens SIRIUS 3RH1911-2NF02 is a solid-state compatible auxiliary switch block with 2 NC contacts, designed for snap-on mounting onto size S00 contactor relays and power contactors. It uses spring-loaded terminals for the auxiliary and control circuit, accepting 2x (0.5... 1.5 mm²) with core-end processing or 2x (0.5... 2.5 mm²) without. The front face carries IP20 protection, and the insulation voltage at AC with pollution degree 3 is rated 690 V. Rated current is 0.3 A at both 24 V and 60 V, and surge voltage resistance is 6 kV. Mechanical service life is 5 000 000 switching cycles typical, with contact reliability of 1 faulty switching per 100 million operations at 17 V, 1 mA.
For volume or scheduled buys, the successor 3RH2911-2NF02 is the recommended path to avoid requalification churn.
The 36.5 mm width and 46 mm depth fit the standard S00 footprint, so it does not increase the panel space beyond the contactor itself. Spring terminals reduce wiring time — no screw torque verification needed.