The Siemens SIRIUS 3RH1911-1HA12-ZW98 is a 4-pole auxiliary switch block with a 22 E contact configuration — 1 normally open and 2 normally closed contacts — designed for snap-on mounting onto contactors and contactor relays in the SIRIUS family. It uses screw-type terminals for the auxiliary and control circuit connections.
Contact ratings and what they mean for fit
The block carries a maximum continuous current of 10 A, but the real-world switching capacity is voltage-dependent across both AC and DC loads. At 24 V AC/DC it is rated 6 A; at 60 V it drops to 2 A; at 110 V it is 1 A; at 220 V it is 0.3 A. For DC-12/DC-13 duty the 24 V rating is 10 A, derating to 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. At AC-15 at 690 V the rating is 1 A. These are not a single '10 A' part — the voltage class of the controlled circuit directly governs which contact rating applies. Insulation voltage is rated 690 V AC at pollution degree 3, with a surge voltage resistance of 6 kV. The front face carries IP20 protection — adequate for enclosed panel mounting but not for exposed washdown areas. Mechanical service life is typical 10 million switching cycles, and contact reliability is specified as one faulty switching per 100 million operations at 17 V, 1 mA — a low-level signal rating that matters when the auxiliary contacts feed a PLC input rather than a power circuit.
Integration into the panel
Snap-on mounting onto the contactor or contactor relay means no additional DIN-rail space is consumed — the block clips directly onto the front of the base device. Dimensions are 36.5 mm wide, 37.5 mm high, and 41.5 mm deep, so it stays within the envelope of a size S00 contactor. Wire range accepts 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) with core-end processing, or 2x (20 to 16) and 2x (18 to 14) AWG for auxiliary contacts.