What it is and where it fits
The Siemens 3RV6901-1A is a lateral auxiliary switch from the SIRIUS family, designed to snap onto the side of a circuit breaker in sizes S00, S0, S2, or S3. It adds one normally-open and one normally-closed contact to the breaker assembly, letting you pick up status or interlock signals directly from the breaker mechanism without extra wiring to a separate relay.
Ratings and what they mean for the panel
The contact ratings are voltage-dependent, which is typical for auxiliary contacts in a motor branch circuit. At 24 V the switch handles 2 A; at 230 V it handles 4 A; at 690 V it handles 10 A. The AC-12 maximum is 10 A, and the AC-15 rating at 690 V is 1 A — the AC-15 figure governs switching of electromagnetic loads like contactor coils, so that lower number is the one to watch when you're feeding a PLC input or a contactor coil from this switch.
Mounting and wiring
The switch uses plug-in fixing — it clips onto the side of the breaker without tools. At 9.5 mm wide, it adds minimal width to the breaker footprint. The screw-type terminals accept 0.5 to 2.5 mm² solid or stranded wire, or two conductors per terminal (2x 0.5…1.5 mm² or 2x 0.75…2.5 mm²). AWG 20 to 14 for the auxiliary circuit.
Compliance
RoHS compliant with a substance prohibition date of 05/01/2012. The part carries the SIRIUS brand and is designed to meet the usual Siemens industrial approvals (CE, UL/CSA for the breaker family).