The Siemens SIRIUS 3RH1911-1FA31-ZW96 is an auxiliary switch block designed for use with contactor relays and power contactors in the SIRIUS family. It provides 3 normally open and 1 normally closed instantaneous contacts, wired via screw-type terminals, and mounts via snap-on onto a DIN rail or directly onto the contactor. The contact reliability is rated at 1 faulty switching per 100 million operations at 17 V, 1 mA, making it suitable for low-level signal switching in control circuits.
Ratings and what they mean for fit
The continuous thermal current rating is 10 A, which governs the maximum load the contacts can carry in uninterrupted service. The switching capacity varies by voltage: at 24 V it is rated 10 A (AC-15), at 230 V it is 6 A, and at 690 V AC-15 it drops to 1 A. For DC loads, the ratings are 6 A at 24 V, 2 A at 60 V, 1 A at 110 V, and 0.3 A at 220 V. These are the values that determine whether the block can handle your specific control load — match the voltage column to your circuit. The insulation rating is 690 V AC with pollution degree 3, and the rated surge voltage withstand is 6 kV. This means the block is suitable for 400 V line-to-line control panels without additional creepage concerns, and it passes the impulse voltage test typical for industrial environments.
Panel integration and wiring
The block snaps onto the contactor or onto a 35 mm DIN rail. Dimensions are 36.5 mm wide, 37.5 mm high, and 41.5 mm deep — it occupies the S00 contactor footprint. The screw terminals accept 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) with ferrule processing, or 2x (20 to 16 AWG) or 2x (18 to 14 AWG) solid/stranded. Front protection class is IP20, so the block is intended for use inside a panel enclosure. Mechanical service life is 10 million switching cycles typical. Operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C. The block is rated for use with contactor relays and power contactors in the SIRIUS family.