What this auxiliary contactor does – and doesn't
The Siemens 3RH2422-1BB40 is a SIRIUS auxiliary contactor, size S00, built for switching control circuits – not motor loads directly. You'd use it to interlock, signal, or extend I/O on a PLC cabinet or motor starter panel. Its coil pulls 4 W at 24 V DC and holds at the same power, so it stays cool in a tight enclosure and doesn't drop out unless you want it to.
Mounting and clearances that matter on a real panel
It snaps onto a 35 mm DIN rail or you can screw-mount it. The dimensions are 57.5 mm high, 90 mm wide, and 73 mm deep – the standard S00 footprint. For ventilation and arcing clearance, leave 10 mm above and below, 10 mm forward, and 6 mm on the sides. Pollution degree 3 means it's fine for factory floors with conductive dust.