What it is and what it does
The Siemens 3RT2016-2HB42 is a SIRIUS coupling contactor in Size S00, designed for switching loads where the control circuit needs isolation from the power circuit — typical in panel interlocking, signal isolation, or as a slave contactor driven by a PLC output. The 24 VDC coil pulls in at 0.7 of rated voltage and holds across the full -25 to +60 °C operating range, so it's reliable on a standard 24 V control supply even in a warm cabinet. Rated operational current is 10 A at 24 V, with derated values at higher voltages — 3 A at 400 V, 1 hp at 230 V — so it handles small motor loads, resistive heaters, or signal-level switching in control circuits.
Mounting and wiring
Snaps onto 35 mm DIN rail per DIN EN 60715, or can be screw-mounted. The 45 mm width and 73 mm depth fit standard panel layouts; clearance of 10 mm above and below, 6 mm to the side is enough for airflow and tool access. Spring-type terminals accept 0.5 to 4 mm² solid or stranded wire, including two conductors per clamp — no screw tightening, just strip and push. That saves time on repetitive wiring in panel builds. Mounting position is flexible: ±180° rotation on a vertical surface, plus ±22.5° tilt forward/backward, so it fits tight enclosures without derating.
Switching performance and duty cycles
Mechanical life is 30 million operations typical — that's the contactor body, not the contacts under load. Actual electrical life depends on the duty class: AC-1 (resistive) allows 1,000 operations per hour, AC-3 (motor starting) and AC-3e (enhanced motor) allow 750 per hour, while AC-4 (plugging/reversing) drops to 250 per hour. Arcing time is 10 to 15 ms, and DC switching times are 7 to 20 ms — fast enough for most sequencing but not for high-speed synchronous transfer.