What it is and what it does
The Siemens SIRIUS 3RH1911-1HA22-ZX95 is a 4-pole auxiliary switch block with 2 normally-open and 2 normally-closed contacts, intended for snap-on mounting onto contactor relays and power contactors in the SIRIUS family. Rated for a maximum continuous current of 10 A, the contacts carry switching loads across a wide voltage range — 6 A at 24 V, 6 A at 125 V, 6 A at 230 V, and 3 A at 400 V — making it suitable for both control-circuit and light power-circuit duty in a panel. The block uses screw-type terminals accepting 2x (0.5…1.5 mm²) or 2x (0.75…2.5 mm²) conductors with core-end processing, and the front face carries an IP20 protection class rating.
Lifecycle and sourcing reality
This part is a phased-out product — the official successor is the SIRIUS 3RH2 series, which offers a modernized footprint and updated ratings.
What the ratings mean for fit
Snap-on mounting means the block clips directly onto the contactor body without tools — no DIN-rail footprint required, which saves panel width but ties the block to the host contactor's form factor. The mechanical service life of 10 million switching cycles typical, combined with a contact reliability of one faulty switching per 100 million operations at 17 V and 5 mA, tells you this block is built for high-cycle control applications where welded or failed contacts would be a nuisance. Surge voltage resistance rated at 6 kV and insulation voltage of 690 V with pollution degree 3 confirm the block can live in an industrial panel environment without flashover concerns.
Integration into the panel
Dimensions are 36.5 mm wide, 37.5 mm high, and 41.5 mm deep — a compact block that adds minimal overhang to the contactor it mounts on. Operating temperature range of -25 to +60 °C and storage range of -55 to +80 °C cover most indoor panel environments.