The Siemens SIRIUS 3RH1911-1FA20-ZW97 is an auxiliary switch block with 2 normally open contacts, designed for snap-on mounting onto contactors and contactor relays in the size S00 frame. It uses screw-type terminals and accepts 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) conductors with core-end processing.
Contact ratings — what they mean on the line
The contacts are rated for a maximum of 10 A, with voltage-dependent switching capacity: 6 A at 24 V, 6 A at 230 V, and 3 A at 400 V. For DC control circuits the ratings are 10 A at 24 V, 4.7 A at 60 V, 3 A at 110 V, and 1.2 A at 220 V. The AC-15 rating at 690 V is 1 A — this is the inductive load rating for contactor coils and solenoid valves at higher line voltages. The insulation voltage is 690 V with pollution degree 3, and surge voltage resistance is 6 kV, so it's suitable for standard industrial panel environments without additional isolation.
Panel integration — what fits where
The block measures 36.5 mm wide, 37.5 mm high, and 41.5 mm deep — compact enough to stack alongside other S00 auxiliaries on a DIN rail. Snap-on mounting means no tools for installation; it clips directly onto the contactor or relay. Operating temperature range is -25 to +60 °C, storage from -55 to +80 °C. Front IP20 rating protects against finger contact during panel access.
Mechanical endurance and contact reliability
Mechanical service life is typical 10 million switching cycles. Contact reliability is specified at 1 faulty switching per 100 million operations at 17 V and 1 mA — a low-level signal rating that matters for PLC inputs and safety circuits where dry switching can cause oxide buildup. For short-circuit protection, the design assumes a gL/gG fuse rated up to 10 A.