What this part is and what it does
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. For a BOM line that needs this exact form-fit-function, the 3RH1911-1HA12-ZX95 is sourced to order against an RFQ through independent distribution — availability and current pricing are confirmed at quote time. 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
Mechanical service life is rated at 10 million switching cycles typical. 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.
Mounting and integration
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. Operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C. Insulation voltage rated at 690 V with pollution degree 3, surge voltage resistance at 6 kV.