What this SIRIUS auxiliary switch block is
The Siemens 3RH1911-2FA22-ZW98 is a SIRIUS auxiliary switch block with a 22 E contact configuration — 2 normally open and 2 normally closed contacts — designed for use with S00-size contactor relays and power contactors. It snaps onto the front of the contactor, adding four auxiliary contacts without increasing the panel depth beyond the 46 mm listed depth of the block itself. The spring-loaded terminals accept 2x (0.5 to 1.5 mm²) with ferrule or 2x (0.5 to 2.5 mm²) solid/stranded, so no screwdriver is needed for the connection — a time-saver on a multi-unit panel build.
Ratings and what they mean for your circuit
The block carries a maximum thermal current of 10 A, but the real-world switching capability depends on the voltage and duty. At 24 V DC it switches 6 A; at 110 V DC that drops to 1 A. For AC-15 inductive loads (solenoids, contactor coils) at 690 V it's rated 1 A. The insulation is rated 690 V AC with degree of pollution 3, and the surge voltage resistance is 6 kV — that's the impulse-withstand level for a 400 V industrial panel environment. Contact reliability is spec'd at 1 faulty switching per 100 million operations at 17 V, 1 mA, so it handles low-energy PLC signals without the intermittent faults that plague cheaper blocks.
Panel integration — snap-on and terminal details
The block snaps onto the front of a S00 contactor — no screws, no tools for the mounting. The spring-loaded terminals are the same type used on the 3RH2 series, so the wiring habit transfers. The IP20 front protection means it's safe for finger contact inside an enclosed panel, but it's not rated for washdown or outdoor exposure. Operating temperature is -25 to +60 °C, storage from -55 to +80 °C, which covers most control cabinet environments.