The Siemens 3RT2316-2AB00 is a SIRIUS S00 contactor — the smallest frame in the SIRIUS family, sized for motor loads up to 4 kW in AC-3 duty at 400 V, with a rated operational current of 9 A. The 24 VAC coil (50/60 Hz) draws 0.25 A at both frequencies, so the control transformer sizing is straightforward. Spring-loaded terminals on both the main circuit and the coil mean no screwdriver torque check on the line — strip, insert, release. It snaps onto 35 mm DIN rail per DIN EN 60715 and can be rotated 180° on a vertical surface or tilted ±22.5°, which helps when the panel layout is tight and the contactor has to fit between existing runs.
That 6 mm side gap is tighter than the vertical ones, so when you're packing multiple contactors in a row, leave that half-inch for arc-chamber breathing. The auxiliary switch option (yes, it's available) adds a side-mount block that stays within the same width envelope.
Wiring and terminal specs
Main circuit terminals accept solid 2x (0.5... 2.5 mm²) or stranded 0.5... 4 mm²; auxiliary contacts take 2x (0.5... 2.5 mm²) solid or stranded. The spring-cage design holds fine-stranded wire without ferrules, but for 4 mm² stranded a ferrule keeps the strands together. Strip length is not listed here, but the spring-loaded mechanism typically needs 8–10 mm. The coil is spring-terminal as well — no separate screw terminals to torque.
Environmental and switching performance
Relative humidity minimum is 10 % — not a sealed unit, so avoid condensing environments without a cabinet heater. The contactor's mechanical life is typical 30 million operations; arcing time is 10–15 ms, and the AC switching time (pickup + dropout) is 7–13 ms. That's fast enough for most motor starting and stopping, but if you need precise timing for a jog or inching sequence, factor in the 7 ms minimum. Rated impulse withstand voltage for the main circuit is 6 kV, which covers standard industrial overvoltage category III.