The Siemens 3RH2911-2HA12-ZX95 is a SIRIUS auxiliary switch with one normally open instantaneous contact, designed to snap onto the front of contactor relays and power contactors in frame sizes S00, S0, S2, and S3. It carries a 6 A rating at 24 V and a 10 A rated value at 24 V, with a surge voltage resistance of 6 kV.
The contact ratings drop as voltage rises: 6 A at 24 V, 2 A at 48 V and 60 V, 1 A at 110 V, 0.9 A at 125 V, 0.3 A at 220 V and 250 V, and 3 A at 400 V. The rated values at higher voltages follow a similar curve — 10 A at 24 V rated value, 4.7 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. These are the limits for the silver-alloy contacts; switching an inductive load below these numbers is safe, but the 17 V, 1 mA contact reliability figure (1 faulty switching per 100 million operations) confirms the contacts are designed for dry-circuit signal integrity as well as power switching.
Mounting and wiring integration
Snap-on mounting to the front of the contactor — no tools, no DIN rail bracket. The terminal accepts 2x (0.5 to 2.5 mm²) solid or stranded wire, or 2x (20 to 14 AWG). For finely stranded wire with ferrules, the range is 2x (0.5 to 1.5 mm²); without ferrules, 2x (0.5 to 2.5 mm²). The 36 mm width and 47.7 mm depth keep the assembly within the contactor's envelope — no extra panel clearance needed beyond what the base contactor already requires.
The mirror contact function per IEC 60947-4-1 is confirmed when used with 3RT2 contactors — this is a safety-relevant feature for load-side isolation monitoring. The part is RoHS-compliant per the substance prohibitance date of October 1, 2009.