The Siemens 3RV1921-1M is a SIRIUS signaling switch designed for circuit breaker sizes S0, S2, and S3. It provides a separate tripped signal and short circuit alarm via one normally-open and one normally-closed contact each, giving the panel builder a clean way to feed status back to a PLC or indicator lamp without tapping the breaker's main circuit.
Contact ratings
The auxiliary contacts are rated for 10 A maximum, with voltage-specific switching capacities: 2 A at 24 V, 0.5 A at 110 V, 0.25 A at 220 V, 4 A at 230 V, 3 A at 400 V, and 10 A at 690 V. At AC-15 duty at 690 V the rated operational current is 1 A. These numbers define the signal load it can break — useful for sizing the downstream input card or relay coil.
Integration and wiring
Mounts via plug-in fixing directly onto the front of the circuit breaker — no DIN rail footprint required. The screw-type terminals accept 2x (0.5 to 1.5 mm²) and 2x (0.75 to 2.5 mm²) solid or finely stranded wire with core end processing. Overall dimensions are 18 mm wide, 90 mm tall, and 68 mm deep, so it stays within the breaker's own envelope. Operating temperature range is -20 to +60 °C; storage range is -50 to +80 °C.