What this auxiliary switch does on a 3RV2 breaker
It plugs into the front of the breaker — no tools, no wiring to the main circuit — and signals the breaker's tripped or closed state back to a PLC or control relay. Rated for a maximum of 2.5 A, the switch carries 1 A at 24 V, 0.5 A at 230 V, and derates to 0.15 A at 60 V. That covers most 24 VDC PLC inputs and 230 VAC control circuits, but watch the 60 V curve if you're running a DC control bus at that level — the 0.15 A limit is the binding constraint. The screw-type terminals accept 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) solid or stranded wire, with the same range for ferruled ends. The IP20 finger-safe front means it meets touch-protection requirements per IEC 60529 for vertical contact from the front — standard for a control-panel environment where operators may reach in.
This auxiliary switch is designed for the 3RV2 family of circuit breakers in frame sizes S00, S0, S2, and S3. It snaps onto the front of the breaker via plug-in fixing — no DIN-rail space consumed beyond the breaker's own 45 mm width. The transverse orientation means the switch sits across the front face, not on the side, so it doesn't increase the breaker's side-by-side mounting footprint. The 3RV2901-1E-ZX90 ships in multi-unit packaging of 500 pieces, which is a volume pack for panel builders or OEMs running a standard BOM line. For a single-unit replacement, you'd order the standard packaging variant — this ZX90 suffix signals the bulk pack.