What this switch does on a contactor
The 3RH2911-2HA11 is a SIRIUS auxiliary switch block with one normally-open (NO) instantaneous contact, designed to snap onto the front of Siemens contactor relays and power contactors in sizes S00, S0, S2, and S3. It adds a signalling or interlocking contact that mirrors the main contactor's state — useful for feedback to a PLC, status lamp, or safety circuit. The mirror contact function per IEC 60947-4-1 is supported when used with 3RT2 contactors, meaning the NO contact cannot close if the main contacts are welded — a critical feature for safety-related isolation.
Contact ratings and what they mean for your circuit
Rated 10 A at 24 V and 6 A at 230 V — the higher current at low voltage suits DC control circuits common in PLC outputs; the 230 V rating covers standard AC pilot duty. For DC loads at higher voltages, the current drops: 2 A at 48 V and 60 V, 1 A at 110 V, 0.9 A at 125 V, and 0.3 A at 220 V and 250 V. AC ratings at 400 V and 440 V are 3 A and 0.5 A respectively — the 400 V figure covers 3-phase control circuits in European panels. Contact reliability is specified at 1 faulty switching per 100 million operations at 17 V, 1 mA — that's the low-energy threshold where oxide films on silver contacts can cause intermittence; this switch is designed to wet through at those levels.
Mounting and panel fit
Snap-on mounting means it clips directly onto the contactor's front without tools — no DIN rail footprint needed for the switch itself, but the contactor is DIN-rail mounted. Dimensions: 47.7 mm deep, 36 mm wide, 41.5 mm high — the width matches the S00/S0 contactor face, so it doesn't overhang and crowd adjacent devices. IP20 front protection means finger-safe against accidental contact, but the switch is not sealed — keep it inside the panel enclosure, not in a washdown zone.
Wiring and termination
Accepts 2 x 0.5–2.5 mm² solid or stranded wire, or 2 x 20–14 AWG — the dual-wire terminals let you daisy-chain the control common without a separate terminal block. For finely stranded wire with ferrules, the range is 2 x 0.5–1.5 mm²; without ferrules, 2 x 0.5–2.5 mm². Surge voltage resistance rated at 6 kV — this switch can handle transient spikes on long control wiring without flashover, matching IEC 60947-5-1 requirements.
Lifecycle and compliance
Listed as current production — this is a standard active SIRIUS accessory, not a legacy or phase-out item. RoHS compliance date marked as 10/01/2009 — the switch meets EU RoHS requirements since that date. Operating temperature range -25 to +60 °C; storage -55 to +80 °C — suitable for most industrial panel environments including unheated warehouses.