What this auxiliary switch does in the panel
The 3RH2911-1FB22-ZX95 is a front-mounted auxiliary switch block for Siemens SIRIUS contactor relays (3RH2) and power contactors (3RT2). It adds 2 normally-open and 2 normally-closed contacts to the base device, with a defined contact sequence: one NO leading, one NC lagging, and the remaining NO and NC instantaneous. Rated for a maximum thermal current of 10 A, with AC-15 switching at 690 V rated at 1 A. DC ratings drop with voltage: 10 A at 24 V, 6 A at 60 V, 3 A at 110 V, 1.2 A at 220 V, 0.5 A at 440 V, and 0.26 A at 600 V — the DC arc extinction limits the current as voltage rises. Snap-on mounting to DIN rail (35 mm) — no tools required. Dimensions are 36 mm wide, 37.5 mm tall, and 43.7 mm deep, fitting standard panel cutouts for SIRIUS contactor accessories.
Sourcing and lifecycle — active production, no obsolescence concern
Sourced to order against your BOM quantity.
Wiring and contact reliability for control circuits
Screw-type terminals accept 2x (0.5 to 1.5 mm²) and 2x (0.75 to 2.5 mm²) conductors, or 2x (20 to 16 AWG) and 2x (18 to 14 AWG). The dual-wire capacity per clamp simplifies daisy-chaining control signals without extra terminal blocks. Contact reliability is specified at 1 faulty switching per 100 million operations at 17 V and 1 mA — this low-level switching performance matters for PLC input circuits where dry contacts must pass milliamps without oxide film resistance. Mechanical service life is 10 million switching cycles typical, which covers most control applications over a 10-15 year panel life without replacement.
Insulation coordination and environmental limits
Rated insulation voltage is 690 V AC at pollution degree 3, with a surge voltage resistance of 6 kV. This means the switch can be used in 400/480 V panels without additional creepage or clearance concerns, even in dusty or conductive environments (PD3). Operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C. Front protection class is IP20 — suitable for enclosed panels where the switch is not exposed to direct contact or dripping water.