What this auxiliary switch does in your panel
The Siemens SIRIUS 3RH2911-2GA22-ZX95 is an auxiliary switch block that snaps onto the front of S00-frame contactor relays. It adds two instantaneous contacts to the base device, giving you feedback or interlock signals without extra wiring runs back to the PLC. The snap-on mounting means it clips directly onto the 3RH2140 or 3RH2440 auxiliary switch base — no tools needed, and it stays put under vibration in a panel cabinet. Rated at 6 A at 24 V and 10 A at the same voltage as a rated value, it handles the typical control-circuit loads you see in a motor starter assembly — contactor coils, indicator lamps, PLC digital inputs. The 6 kV surge voltage resistance means it withstands switching transients on a 400 V line without flashover, which is what you need when the auxiliary contacts sit in the same enclosure as the power wiring.
Current ratings across the voltage range — what they mean for your BOM
This switch block carries two sets of current ratings: one for the standard switching duty and one for the rated value. At 24 V you get 6 A standard and 10 A rated value; at 110 V it drops to 1 A standard and 3 A rated value. The pattern tells you the contacts are silver-alloy and sized for DC control circuits where the arc stretches with voltage. If your BOM calls for switching a 24 VDC relay coil at 2 A, this part has headroom. If you need to break a 220 VDC solenoid at 1 A, the 0.3 A standard rating says you need a different block or a DC-rated interposing relay. The contact reliability spec — one faulty switching per 100 million operations at 17 V, 1 mA — confirms the contacts are gold-flashed or bifurcated for dry-circuit use. That matters when the auxiliary switch feeds a PLC input that sees micro-amp leakage; you won't get false signals from oxidation.
Wiring and termination — what fits the terminals
The terminals accept two conductors per clamp: 2x (0.5... 2.5 mm²) solid or stranded, or 2x (20... 14 AWG). Finely stranded wire with ferrules goes up to 1.5 mm² per clamp. The spring-cage design holds the wire without retightening, but strip length matters — aim for 8–9 mm to avoid exposed copper past the cage.
Physical fit — dimensions for panel layout
The block measures 47.7 mm deep, 36 mm wide, and 41.5 mm high. The 36 mm width matches the standard S00 contactor footprint, so it doesn't widen the assembly beyond the base device. Depth of 47.7 mm includes the snap-on latch; plan for 50 mm clearance behind the panel door if you're mounting the contactor on a DIN rail.