Auxiliary switch block, 4 NO, spring terminals — lifecycle note
The Siemens 3RH1911-2GA40 is a SIRIUS auxiliary switch block with 4 normally-open contacts arranged per EN 50011 (40 E contact designation). It snaps onto 3RH1 contactor relays and power contactors via the snap-on mounting feature, using spring-loaded terminals for the auxiliary and control circuits — no screwdriver needed for the wire connection, just strip and push. This is a phased-out product. The manufacturer lists the preferred successor as 3RH2911-2GA40. If your BOM is locked to the 3RH1911 footprint and terminal style, the successor uses the same snap-on mounting and spring-clamp interface — verify the contact arrangement matches your control scheme. Rated for 10 A maximum, with AC-15 utilization at 690 V rated at 1 A. Contact reliability is specified at 1 faulty switching per 100 million operations at 17 V, 1 mA — suitable for low-energy PLC inputs and signal-level switching where oxide film can be a concern.
Mounting and wiring
Snap-on mounting directly onto the contactor relay or power contactor — no DIN rail required for the block itself. The spring-loaded terminals accept 2x (0.5... 1.5 mm²) with core-end processing, or 2x (0.5... 2.5 mm²) without. AWG equivalents: 2x (20... 14). Dimensions: 46 mm depth, 36.5 mm width, 37.5 mm height. The IP20 front protection means it's intended for enclosure interiors — not for exposed washdown areas.
Electrical ratings and environmental limits
The 4 NO contacts carry rated currents at various voltages: 10 A at 24 V (rated value), 6 A at 24 V (other listing), 6 A at 125 V, 6 A at 230 V, 6 A at 250 V, 3 A at 400 V, 0.3 A at 220 V. The AC-15 rating at 690 V is 1 A. Surge voltage resistance is 6 kV; insulation voltage at pollution degree 3 is 690 V AC. Operating temperature range -25 to +60 °C; storage range -55 to +80 °C. Mechanical service life is 10 million switching cycles typical.