The Siemens SIRIUS 3RH1911-1HA12-ZX95 is a 4-pole auxiliary switch block with 1 normally open and 2 normally closed contacts, designed for snap-on mounting to contactor relays and power contactors in the SIRIUS family. Rated at 10 A maximum, the contacts handle a range of control voltages: 6 A at 24 V, 6 A at 125 V, 6 A at 230 V, 6 A at 250 V, 3 A at 400 V, 2 A at 60 V, 1 A at 110 V, and 0.3 A at 220 V, giving you the flexibility to use it across different control circuits without recalculating ratings. The block uses screw-type terminals accepting 2x (0.5...1.5 mm²) and 2x (0.75...2.5 mm²) conductors, or 2x (20...16) and 2x (18...14) AWG, and carries an IP20 protection rating on the front — standard for enclosed panel mounting.
Lifecycle reality — phased out, successor named
This part is a phased-out product. The manufacturer lists the SIRIUS 3RH2 as the official successor series. No spare, no sleep: if you're holding a legacy cabinet with this block, securing a critical spare now avoids a line-down scramble later.
Contact reliability and mechanical life
Contact reliability is specified at one faulty switching per 100 million operations at 17 V, 5 mA, and at 17 V, 1 mA for auxiliary contacts — useful for PLC-level signal switching where low-energy circuits must not miss a pulse.
Snap-on mounting onto a contactor relay or power contactor — no DIN rail required, no extra hardware. Dimensions are 41.5 mm deep, 36.5 mm wide, 37.5 mm high, so it adds minimal depth to the contactor assembly. Insulation voltage rated at 690 V with pollution degree 3, surge voltage resistance at 6 kV.