What it is and what it does
The Siemens 3RH1344-2BK80 is a SIRIUS auxiliary contactor — a control-circuit relay built into the size S00 contactor footprint. It gives you four normally-open instantaneous contacts, each rated for switching at the voltages you'd see in a typical 24 VDC or 230 VAC control panel: 10 A at 24 V, 6 A at 230 V, 3 A at 400 V, 2 A at 500 V, and 1 A at 690 V. The coil pulls 3.2 W DC to close and holds at the same power, so the thermal load on the panel stays predictable. Out here in the grease, on a lube route or a conveyor line, what that means is you've got a contactor that'll handle the signal side of a motor starter or a valve manifold without breaking a sweat. The IP20 front keeps fingers and tools off the terminals, and the -25 to +60 °C operating range covers most plant-floor conditions short of a freezer.
Mounting and panel fit
It mounts by screw or snaps onto a DIN rail. The 45 mm width and 60 mm height match the S00 contactor footprint. Depth is 114 mm. Terminals accept 2x (0.25 to 2.5 mm²) solid or stranded, or 2x (24 to 14 AWG). Strip length is what you'd expect for a spring-cage or screw clamp — no special tooling. The mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward/backward, so you can fit it into tight corners or angled subpanels.
Lifecycle and sourcing
For compliance, it carries a RoHS substance prohibition date of July 1, 2006, which covers the EU RoHS directive. Surge voltage resistance is rated at 6 kV, matching the typical coordination level for industrial control panels per IEC 60947. Pollution degree 3 means it's rated for conductive pollution in a normal factory environment — no conformal coating required for most applications.
Contact reliability and switching life
The contacts are rated for 10 million mechanical operations typical, and the contact reliability spec says one incorrect switching operation per 100 million at 17 V and 1 mA. That's the low-energy end — dry circuits, PLC inputs, signal-level loads. If you're switching a 24 VDC relay coil or a contactor coil, the 10 A rating at 24 V gives you plenty of headroom. Shock resistance is 10g for 5 ms and 5g for 10 ms — enough for most industrial machinery, including conveyors and pumps. Storage temperature range of -55 to +80 °C covers shipping and warehouse extremes.