What it is and what it does
The Siemens SIRIUS 3RH1911-2NF11 is a solid-state compatible auxiliary switch block designed for use with SIRIUS contactor relays and power contactors. It provides one normally open and one normally closed contact, rated for switching at 24 V and 60 V at 0.3 A, in a compact size S00 housing that snaps onto the contactor. The spring-loaded terminals accept 2x (0.5... 1.5 mm²) with ferrule or 2x (0.5... 2.5 mm²) solid/stranded without, making for quick wiring in a panel build. The insulation voltage is rated at 690 V AC at pollution degree 3, with a surge voltage resistance of 6 kV, so it holds up in industrial panels where line transients are common. Mechanical life is 5 million switching cycles typical, and contact reliability is rated at 1 faulty switching per 100 million operations at 17 V, 1 mA — solid for low-level signal switching in PLC or safety circuits.
Sourcing and lifecycle reality
This part is a phased-out product. The official Siemens successor is the SIRIUS 3RH2911-2NF11, which is the preferred drop-in replacement. If you are filling a BOM line or maintaining an existing panel, you can source the 3RH1911-2NF11 through independent distribution — it is quoted to order against an RFQ, with availability and current pricing confirmed at quote time. For new designs, specify the 3RH2911-2NF11 to avoid a future last-time-buy scramble.
Panel integration notes
Snap-on mounting onto a 35 mm DIN rail or directly onto the contactor. The 36.5 mm width and 46 mm depth fit the S00 footprint, so it does not steal extra rail space. IP20 on the front means it is protected against finger contact but not washdown — keep it inside a closed panel. Operating temperature range is -25... +60 °C; storage from -55... +80 °C.