What it is and what it does
The Siemens SIRIUS 3RT2016-1JB42 is an S00-frame coupling contactor — a compact, magnetically held switch designed to close and open control circuits in industrial panels. The 24 VDC coil pulls in at 0.7 of rated voltage and drops out reliably, with operate and release times in the 38–65 ms range. It's built for the SIRIUS modular system, so it shares the same 45 mm width and DIN-rail footprint as the rest of the S00 family. The main contacts are rated 10 A at 24 VDC for resistive loads (AC-1), and the contactor handles switching frequencies up to 1000 cycles per hour on AC-1 duty, 750 on AC-3 motor duty. Mechanical life is rated at 30 million cycles — it'll outlast most of the gear it's switching.
Panel fit and wiring
Mounts on standard 35 mm DIN rail per DIN EN 60715, with screw and snap-on fastening. The S00 frame takes up 45 mm of rail width, 58 mm tall, 73 mm deep — fits in a standard 200 mm deep enclosure with room for gland plates. Clearance: 10 mm upwards and forwards, 6 mm at the sides, 10 mm downwards. Screw-type terminals on the magnet coil accept solid or stranded wire from 0.5 to 4 mm² (single) or two conductors up to 1.5 mm² each. No auxiliary switch block on this variant — it's a bare coupling contactor, so if you need auxiliary contacts, you'll add a separate block from the SIRIUS range.