The Siemens SIRIUS 3RV1901-1C is a lateral auxiliary switch that mounts on the side of SIRIUS 3RV circuit breakers in sizes S00, S0, S2, and S3. It provides two normally-closed (NC) instantaneous contacts — no NO or changeover contacts on this variant. Rated for AC-12 duty, the contacts carry 10 A at 690 V and 4 A at 230 V. At 24 V the rating is 2 A; at 110 V it drops to 0.5 A; at 220 V it is 0.25 A. The AC-15 rating at 690 V is 1 A. These ratings govern the inductive or resistive load you can switch through the auxiliary contacts. The switch uses screw-type terminals accepting 0.5–2.5 mm² solid or stranded wire, or 2x (0.5–1.5 mm²) and 2x (0.75–2.5 mm²) with ferrules. For AWG, it accepts 2x 18–14. The 9.5 mm width and 70 mm depth let it fit into the standard DIN-rail footprint alongside the breaker.
The 3RV1901-1C is a phased-out product. The manufacturer lists the successor as the SIRIUS 3RV2 series, with the preferred replacement order code 3RV2901-1C.
Integration notes
Mounts via plug-in fixing to the side of the circuit breaker — no DIN rail slot consumed beyond the breaker itself. The 9.5 mm width means it adds minimal panel fill.