The Siemens SIRIUS 3RV2901-2B is a lateral auxiliary switch designed to snap onto 3RV2 circuit breakers in sizes S00, S0, S2, and S3. It provides two normally open (NO) instantaneous contacts via spring-loaded terminals, eliminating the need for screwdriver torque control during panel wiring. The 9.5 mm width keeps the assembly compact on the DIN rail, and the plug-in fixing method means it mounts directly onto the breaker side without additional hardware.
The 3RV2901-2B carries rated operational currents across multiple voltage levels: 2 A at 24 V, 0.5 A at 110 V, 0.25 A at 220 V, 4 A at 230 V, 0.25 A at 250 V, 3 A at 400 V, and 10 A at 690 V. These figures cover control-circuit switching for most industrial AC voltages encountered in panel applications. For AC-15 duty (solenoid and electromagnetic loads), the switch is rated 1 A at 690 V. The maximum AC-12 (resistive load) current is 10 A. These ratings define the load type the contacts can reliably break — AC-15 is the relevant one for contactor coils and relay loads.
Wire termination uses spring-loaded terminals accepting 0.5 to 2.5 mm² solid or stranded conductors, or 2x (0.5 to 2.5 mm²) solid. For AWG, this corresponds to 20 to 14 gauge. The switch occupies 9.5 mm of DIN-rail width and stands 90 mm tall with a 68 mm depth. It is designed to be mounted on the side of the circuit breaker, so it does not consume additional rail space beyond the breaker footprint. The substance prohibition date of October 1, 2009 indicates RoHS compliance per EU Directive 2002/95/EC.