What it is and where it lands
The Siemens 3RH1911-2FA22 is a SIRIUS auxiliary switch designed to snap onto the front of S00-size contactors and contactor relays — no tools, no extra wiring brackets. It adds two instantaneous N/O contacts to the base device, giving you feedback or interlock signals without increasing panel depth beyond the 46 mm the switch itself takes up. Rated for AC-15 duty (solenoid and electromagnetic loads), it handles 10 A at 24 V, 6 A at 230 V, and 3 A at 400 V. For DC switching, the curve drops: 6 A at 24 V, 2 A at 48/60 V, 1 A at 110 V, 0.3 A at 220/250 V. The AC-15 rating at 690 V is 1 A, so it covers control circuits across common line voltages. It's a mirror contact per IEC 60947-4-1 when paired with a 3RT1 contactor — meaning the N/O contact won't weld closed if the main power contacts weld. That makes it usable in safety circuits where you need positive-guided feedback of the contactor state.
Mounting and panel fit
Snaps onto the front of S00 contactors (3RT1, 3RH1) — the 36.5 mm width and 37.5 mm height keep it within the contactor envelope, so you don't lose a DIN slot. The 46 mm depth adds to the contactor's own depth; check your enclosure depth if you're stacking multiple auxiliaries. Front protection is IP20 — fine inside a closed panel, not for washdown zones. Wire termination accepts 2x 0.5–2.5 mm² solid/stranded or 2x 20–14 AWG, with ferruled ends down to 1.5 mm². Strip length is standard for screw-clamp terminals.
Compliance and documentation
RoHS compliant per the substance prohibition date of July 1, 2006. The mirror-contact feature satisfies IEC 60947-4-1 requirements for safety-related applications. No UL or CSA listing is stated in the evidence, but the IEC ratings cover most global installations outside North America.