What this auxiliary switch block does
The 3RH2911-2GA04 is a front-mounted auxiliary switch block for Siemens SIRIUS contactor relays, adding four normally-closed (NC) contacts to the relay base. It snaps onto the front of 3RH2140 and 3RH2440 contactor relays, physically coded per EN 50011 to prevent mismating. Rated for a maximum continuous current of 10 A, with AC-15 switching capacity of 1 A at 690 V — sufficient for most PLC and relay coil loads in control panels. The contact reliability spec (1 faulty switching per 100 million operations at 17 V, 1 mA) means it handles dry switching without stutter.
Termination and wiring
Spring-loaded terminals accept 2x (0.5... 1.5 mm²) with ferrule or 2x (0.5... 2.5 mm²) without ferrule — the push-in grip holds solid and stranded wire without retightening. AWG equivalent is 2x (20... 14). Snap-on mounting to the contactor relay front saves DIN-rail space — no additional rail footprint beyond the relay itself. The 36 mm width and 47.7 mm depth keep the assembly compact inside a panel.