What it is and what it does
The Siemens SIRIUS 3RH2140-1SB40-ZX95 is a coupling relay — a size S00 auxiliary contactor block — designed for switching auxiliary circuits in control panels. It carries 4 normally-open instantaneous contacts rated at 10 A at both 24 V and 230 V, making it a straightforward interface between a PLC output or pushbutton and a higher-current load like a contactor coil or indicator bank. The coil pulls in at 24 VDC with a closing power of 1.6 W and includes a built-in suppressor diode, so you don't need to add external flyback protection across the coil terminals — the diode handles the inductive kick on de-energization. That's one less component to spec and wire per the datasheet.
Panel fit and mounting
Mounts via screw or snap-on onto standard 35 mm DIN rail. The S00 footprint measures 45 mm wide, 57.5 mm tall, and 73 mm deep — a compact envelope that leaves room for adjacent devices in a crowded enclosure. The mounting position is flexible: ±180° rotation on a vertical surface, plus ±22.5° tilt forward or backward, so you can orient the relay to suit the wiring layout without worrying about derating the contacts. Clearance requirements are tight: 10 mm upward, 10 mm forward, 10 mm downward, and 6 mm at the sides. That's enough for airflow and tool access in a typical panel layout. Wire terminations accept 2 x 0.5 to 1.5 mm² solid or stranded, 2 x 0.75 to 2.5 mm², or 2 x 4 mm² — covers most control-circuit wiring gauges.
Electrical ratings and environment
Rated operational current is 10 A at 24 V and 230 V, with lower values at higher voltages: 4.7 A at 60 V, 3 A at 110 V and 400 V, 1.2 A at 220 V, 0.5 A at 440 V, 2 A at 500 V, 0.26 A at 600 V, and 1 A at 690 V. These are the AC-15 / DC-13 switching capacities per the datasheet — use the voltage-specific figure when sizing for a given circuit. Operating temperature range is -25 to +50 °C, storage from -55 to +80 °C. Pollution degree 3 means it's rated for the conductive-dust and condensation environment typical of industrial control panels — no conformal coating required for most installations. Relative humidity minimum is 10 %, so it's fine in dry climates or air-conditioned rooms. Mechanical endurance is 30 million operations typical. Electrical switching frequency is rated at 10 000 cycles per hour at AC, with an arcing time of 10 to 15 ms. For DC switching, the minimum on-time is 5 to 20 ms — relevant when driving fast-cycling loads like solenoid valves.
Lifecycle and sourcing
RoHS compliance is confirmed with a substance prohibition date of 10/01/2009, covering the original EU RoHS directive. The product extension auxiliary switch is listed as 'No' — this is the base relay without add-on contact blocks, so plan for that if your circuit needs more than 4 NO contacts.