What this auxiliary switch block does
The 3RH2911-1HA22-ZX95: This is a front-mounted auxiliary switch block for the SIRIUS contactor family — 2 normally-open and 2 normally-closed contacts, screw-type terminals, designed to snap onto 3RT2 power contactors or 3RH2 contactor relays. The contact arrangement is 1 NC, 1 NC, 1 NO, 1 NO on the current path, giving you two isolated NC and two isolated NO circuits in a single 36 mm wide block.
Current ratings — what they mean for your circuit
Rated 10 A maximum, but the actual switching capacity depends on the circuit voltage: 6 A at 24 V AC/DC, 6 A at 125 V, 6 A at 230 V, 3 A at 400 V, and 0.3 A at 220 V DC. For DC-13 duty (solenoid/brake loads), the ratings drop further: 10 A at 24 V, 4.7 A at 60 V, 3 A at 110 V, 1.2 A at 220 V, 0.5 A at 440 V, 0.26 A at 600 V — the DC arc extinguishes slower, so derate accordingly. At AC-15 (inductive loads like contactor coils) at 690 V, the rated current is 1 A — the insulation voltage is 690 V AC at pollution degree 3, so this block can live in a 400/480 V panel with margin.
Service life and contact reliability
Mechanical service life is 10 million switching cycles typical — for a contactor that cycles once per minute, that's about 19 years of continuous operation before the mechanism wears out. Contact reliability is specified at 1 faulty switching per 100 million operations at 17 V, 1 mA — this matters for PLC input circuits where dry switching (low voltage, low current) can cause oxide film issues on standard contacts.
Panel integration and wiring
Snap-on mounting to DIN rail — no screws needed for the block itself. Dimensions are 36 mm wide, 43.7 mm deep, 37.5 mm high, fitting standard enclosure layouts. Screw-type terminals accept 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) with core end processing, or 2x (20 to 16 AWG) or 2x (18 to 14 AWG) for solid/stranded wire. Front protection is IP20 — finger-safe inside an enclosure but not rated for washdown or outdoor exposure without a cabinet.
Surge and environmental ratings
Surge voltage resistance is 6 kV — this block can handle transient overvoltages common in industrial power distribution without flashover. Operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C — suitable for most indoor industrial environments including unheated warehouses.