The Siemens 3RV1991-1FA1 is a 2-meter, 12-pole connecting cable designed specifically for the auxiliary switch blocks on 3RV1.5-8 motor starter protectors. It carries the signal from the auxiliary contacts back to the control panel or PLC input module — a straightforward part, but one that has to match the exact pinout and connector keying of the 3RV1.5-8 family.
This cable mates with the auxiliary switch block mounted on the side of a 3RV1.5-8 motor starter protector. The 12-pole connector carries both normally-open and normally-closed auxiliary contact signals back to the control wiring. In a typical panel, you'd run this cable from the breaker's auxiliary switch to a terminal block or directly to a PLC input card — it saves having to run individual wires from each auxiliary contact.
Panel fit and routing
At 2 meters, the cable length is enough to reach from a DIN-rail-mounted 3RV1 breaker to a nearby terminal strip or I/O module in a standard enclosure. The 12-pole connector is keyed to prevent miswiring. No special tools needed beyond a small flat-blade screwdriver for the terminal block end if you're terminating there.