The Siemens 3RH2911-2DA20 is a lateral auxiliary switch block from the SIRIUS family, designed to snap onto 3RT2 contactors. It carries two normally-open (NO) contacts on each side — left terminals 43/44 and 53/54, right terminals 23/24 and 33/34 — all wired via spring-loaded terminals that accept 2x (0.5…1.5 mm²) with ferrule or 2x (0.5…2.5 mm²) solid, no tool needed for the wire termination.
The headline maximum of 10 A is the thermal current (Ith) through the contact path, but the real-world switching capability depends on voltage and duty. At 24 V it handles 10 A (resistive) or 6 A (inductive, AC-15 typical); at 690 V AC-15 it drops to 1 A — the arc energy at higher voltage limits the make/break capacity. The insulation rating of 690 V AC (pollution degree 3) and surge withstand of 6 kV mean this switch is rated for 400 V line-to-line control circuits without needing extra clearance.
Snap-on integration with 3RT2 contactors
This block mounts on the left side of 3RT2 contactors via the snap-on fastening method — no screws, no DIN rail footprint consumed beyond the contactor's own width (10 mm for the switch block itself).