The Siemens SIRIUS 3RH2911-2XA20-0MA0 is a front-mounted auxiliary switch block delivering 2 normally-open contacts (53/54, 63/64) for 3RT2 power contactors and 3RH2 contactor relays. It uses spring-loaded terminals — strip length around 8 mm, accepts 2x (0.5... 1.5 mm²) with ferrules or 2x (0.5... 2.5 mm²) solid — and snaps onto the contactor front without tools.
Switching ratings and what they mean for your circuit
Maximum continuous current is 10 A, but the real-world switching capacity depends on voltage and load type. At 24 V AC/DC it handles 6 A; at 110 V it drops to 1 A; at 220-250 V it's back to 6 A (resistive). For DC loads the curve is steeper: 10 A at 24 V, 4.7 A at 60 V, 1.2 A at 220 V, and 0.26 A at 600 V. The AC-15 rating at 690 V is 1 A — that's the inductive load case for solenoid valves and contactor coils. Insulation voltage is 690 V at pollution degree 3, with 6 kV surge withstand. That means it's rated for 480 V panels without derating, and the surge rating covers most industrial transient environments.
Panel fit and mounting
Snap-on mounting to the contactor front — no DIN rail required. Dimensions are 36 mm wide, 47.7 mm deep, 41.5 mm high. Front IP20 means finger-safe when installed in a closed panel. Mechanical life is 10 million operating cycles, and contact reliability is rated at 1 faulty switching per 100 million operations at 17 V, 1 mA — that's the dry-circuit spec for PLC-level signals.