Auxiliary switch for 3RT2 contactors and 3RH2 relays
The 3RH2911-1HA01-ZX95 is a front-mounted auxiliary switch block for Siemens SIRIUS 3RT2 contactors and 3RH2 contactor relays, providing one normally-closed (NC) contact path. It snaps onto the front of the contactor or relay without additional hardware, adding a spare NC pole for status feedback or interlocking in the same DIN-rail footprint.
Switching capacity across the voltage range
The auxiliary contact is rated for a maximum of 10 A, with AC-15 rated operational currents specified per voltage: 10 A at 24 V, 6 A at 125/230/250 V, 3 A at 400 V, and 0.5 A at 440 V. At higher control voltages the current capability drops significantly — 0.3 A at 220 V and 0.26 A at 600 V — so the contact must be derated when switching 600 V control circuits. The insulation rating is 690 V AC at pollution degree 3, with a surge voltage withstand of 6 kV, matching the typical isolation requirements for industrial control panels.
Mechanical endurance and contact reliability
Rated for 10 million mechanical switching cycles, this auxiliary block outlasts most contactor main poles in cyclic service — it is not the wear item in the assembly. Contact reliability is specified at one faulty switching per 100 million operations at 17 V, 1 mA, meaning it handles low-energy PLC-level signals without the oxide-film problems that plague power contacts at dry-circuit levels.
Wiring and environmental limits
Screw-type terminals accept two conductors per clamp: 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²), with equivalent AWG ranges of 2x (20 to 16) and 2x (18 to 14). Operating temperature range is -25 to +60 °C, storage from -55 to +80 °C, and the front face carries IP20 protection — suitable for enclosed panel mounting but not for exposed washdown areas.