The Siemens SIRIUS 3RH1921-1CA10-ZW97 is a snap-on auxiliary switch designed for S0-size contactor relays and power contactors. It carries one normally-open instantaneous contact rated 10 A at 24 V, with additional AC-15 ratings up to 1 A at 690 V and AC-12 maximum 10 A. The contact is a mirror contact per IEC 60947-4-1 when used with 3RT1 contactors, providing a mechanically linked confirmation of the main contact position for safety circuits.
Mounting and integration
Snaps onto the front of S0 contactors via the fastening method — no tools needed for installation. Dimensions are 10 mm wide, 38 mm high, 51 mm deep, fitting within the standard S0 footprint. The IP20 protection class on the front suits enclosed panel use; not rated for washdown or outdoor exposure.
Contact ratings and switching capability
Rated operational currents span multiple voltages: 6 A at 24 V and 230 V, 2 A at 48 V and 60 V, 1 A at 110 V, 0.9 A at 125 V, 0.3 A at 220 V and 250 V, and 3 A at 400 V. The AC-15 rating at 690 V is 1 A, covering inductive loads typical of contactor coils and solenoid valves. AC-12 maximum is 10 A for resistive loads. Contact reliability is specified as 1 faulty switching per 100 million operations at 17 V, 1 mA — a figure that matters for low-energy signal circuits where oxide films can cause intermittency.
Lifecycle and compliance
Listed as current production. Mechanical service life is 10 million operating cycles typical. Surge voltage resistance is 6 kV. Operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C. RoHS compliance date is 07/01/2006. Wire connection accepts 2x (0.5 to 1.5 mm²) solid/stranded or 2x (0.75 to 2.5 mm²) finely stranded with ferrule, plus AWG equivalents 20–16 and 18–14.