The Siemens SIRIUS 3RH1911-2GA04 is a 4-pole auxiliary switch block with a 44E contact configuration — 4 normally closed contacts — laid out per EN 50011. It snaps onto a contactor relay or power contactor in the SIRIUS family, extending the auxiliary contact set without extra wiring space. The spring-loaded terminals accept 2x (0.5 to 2.5 mm²) stranded without ferrules, or 2x (0.5 to 1.5 mm²) with core-end processing, matching the standard panel-building practice for control circuits. The 46 mm depth and 36.5 mm width keep the block within the footprint of the base contactor, so it does not push the DIN-rail layout wider.
Ratings and what they mean for the panel
The block carries a maximum thermal current of 10 A, but the real-world switching capacity depends on voltage and load type. At 24 V it handles 6 A (AC-15) or 10 A (resistive); at 230 V the AC-15 rating drops to 6 A, and at 400 V it is 3 A. For DC switching the numbers tighten further — 0.3 A at 220 V DC, 0.26 A at 600 V DC. These are the values that govern whether the block closes the cycle on a solenoid valve or a small contactor coil. The rated insulation voltage is 690 V AC at pollution degree 3, with a surge voltage resistance of 6 kV. The IP20 front protection means it is safe for finger access inside an enclosed panel but not for washdown or outdoor exposure. Mechanical service life is rated at 10 million operating cycles typical, and contact reliability is specified at 1 faulty switching per 100 million operations at 17 V, 1 mA — relevant for low-energy PLC inputs where contact oxidation can cause intermittent faults.
Mounting and integration
Snap-on mounting onto a SIRIUS contactor relay or power contactor. The block shares the same DIN-rail clip as the base device — no additional rail space consumed. The 37.5 mm height keeps it below the arc chamber of most contactors in the series.