The Siemens SIRIUS 3RH1911-1HA12-ZW97 is a 4-pole auxiliary switch block with a 22 E contact configuration — 1 normally open and 2 normally closed — intended for use with contactor relays and power contactors.
This block carries a maximum thermal current of 10 A, but the real-world switching capacity depends on the voltage and duty. For DC-13 at 24 V it handles 6 A; at 110 V it drops to 1 A; at 220 V it's 0.3 A. The AC-15 rating at 690 V is 1 A. That means for a 24 VDC pilot circuit you get the full 6 A, but for a 220 VDC interposing relay you're limited to 0.3 A — a common trap when reusing this block across different control voltages.
This is a phased-out product. The official successor is the SIRIUS 3RH2 series. If you have a BOM line frozen on the 3RH1911-1HA12-ZW97, the 3RH2 is the drop-in replacement path — verify the terminal arrangement and contact configuration against your panel layout before committing.
The block is 41.5 mm deep, 36.5 mm wide, and 37.5 mm high — it fits the S00 contactor footprint. Screw terminals accept 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) with core-end processing, or 2x (20 to 16) and 2x (18 to 14) AWG.
Mechanical service life is 10 million switching cycles typical. Surge voltage resistance is 6 kV, and the insulation voltage at pollution degree 3 is 690 V AC.