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.
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. 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. Relative humidity minimum is 10 %, so it's fine in dry climates or air-conditioned rooms. Mechanical endurance is 30 million operations typical. For DC switching, the minimum on-time is 5 to 20 ms — relevant when driving fast-cycling loads like solenoid valves.
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.