What it is and what it does
The Siemens 3RH1344-1AU00-ZW96 is a SIRIUS auxiliary contactor — a switching device that extends the signal-contact capacity of a main contactor or starter assembly. It carries 4 normally-open instantaneous contacts, meaning it closes the circuit immediately when the coil picks up, with no built-in delay. That's 4 NO contacts you can wire into a PLC input, a status lamp, or a safety chain without loading the main contactor's auxiliary block.
Key ratings and what they mean for fit
Rated operational current varies by voltage: 10 A at 24 V, 6 A at 230 V, 3 A at 400 V, and 1 A at 690 V. That 690 V / 1 A rating is what you need for 690 VAC control circuits common in European industrial panels — most auxiliary contactors top out at 400 V. The surge voltage resistance is 6 kV, which puts it in the IEC 60947-5-1 overvoltage category III range for fixed-installation isolation. Contact reliability is rated at one incorrect switching operation per 100 million operations at 17 V, 1 mA. That low-level switching spec matters for direct PLC input sensing — dry contacts at 17 V won't self-clean, so you need a contactor that reliably closes that low-energy circuit. The 10g / 5 ms and 5g / 10 ms shock resistance means it stays closed under moderate vibration on a conveyor drive or compressor skid.
Mounting and wiring in the panel
Fastening is screw and snap-on mounting. The S00 frame size is 45 mm wide, 57.5 mm tall, 111 mm deep. Wire capacity accepts 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or 2x 4 mm² solid conductors. That covers standard 1.5 mm² control wiring up to 4 mm² for heavier load circuits on the same contact block. Pollution degree 3 means it's rated for conductive pollution environments — typical for unsealed industrial control panels where dust and humidity are present.
What you get on the front
Front protection class is IP20 — finger-safe terminals but not sealed against water. Operating temperature range is -25 to +60 °C, storage and transport range is -55 to +80 °C. That -55 °C storage floor means it survives cold warehouse or trucking in winter without damage, even if the panel isn't powered. Substance prohibition date is July 1, 2006, which aligns with the original EU RoHS directive. The part is RoHS-compliant for the standard six restricted substances. No REACH or UL listing is explicitly stated in the evidence, but the SIRIUS series typically carries CE and UL/CSA certification for the broader line.