What it is and what it does
The Siemens SIRIUS 3RH2140-1BC40 is a size S00 auxiliary contactor with 4 normally open instantaneous contacts, designed for control-circuit switching in industrial panels. It screws or snaps onto 35 mm DIN rail, occupying 45 mm of width — a standard slot for a four-pole auxiliary block. Rated switching currents span 10 A at 24 V AC/DC and 230 V AC, 3 A at 400 V AC, and 1 A at 690 V AC — covering typical control voltages from 24 V to 690 V. The DC coil draws 4 W closing and holding, so the PLC or relay driving it needs to source at least that. Operating temperature range is -25 to +60 °C, storage -55 to +80 °C, with relative humidity down to 10 %. Pollution degree 3 suits it for industrial environments with conductive dust or condensation.
Panel integration and wiring
Mounts on 35 mm DIN rail via the integrated snap-on clip, plus screw holes for permanent fastening. The mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward/backward — useful when the panel layout forces an odd angle. Terminals accept 2× (0.5 to 1.5 mm²), 2× (0.75 to 2.5 mm²), or 2× 4 mm² solid or stranded wire. Clearance to adjacent components: 10 mm upward, downward, and forward; 6 mm sideways. The 73 mm depth means it stays within the standard DIN-rail envelope.