What it is and where it fits
The Siemens 3RT2023-2NB30 is a SIRIUS power contactor in the Size S0 frame. The Size S0 footprint is 102 mm high, 45 mm wide, 107 mm deep. The coil is rated for 21–28 VDC. Inrush current peaks at 3 A, and the holding current settles to about 0.7 A (initial value). The contactor includes an auxiliary switch (1 N/O + 1 N/C, based on the 18–8 contact configuration for main contacts), which gives feedback to the PLC or safety relay without needing a separate add-on block. Spring-type terminals on the coil save wiring time — no screwdriver needed for the control circuit.
Mounting and clearances
Mounting is screw and snap-on onto 35 mm DIN rail per DIN EN 60715. The mounting position is flexible: +/-180° rotation on a vertical surface, and can be tilted forward/backward by +/-22.5° on a vertical surface. That covers most panel layouts — even tight corners or angled sub-panels. Clearance requirements: 10 mm upwards, 10 mm forwards, 10 mm downwards, and 6 mm at the side. That's tight enough to pack multiple contactors side-by-side in a standard 600 mm wide enclosure. The 45 mm width per unit means you can fit 13 contactors per meter of DIN rail.
Switching performance and lifecycle
The contactor is rated for 1 000 switching cycles per hour for AC-1, AC-2, AC-3, and AC-3e duty, and 300 cycles per hour for AC-4 (plugging/inching). The mechanical life is typical 10 million operations — that's a solid 11 years at 1 000 cycles/hour running 24/7. The arcing time is a consistent 10 ms, which helps with contact erosion predictability. Operating temperature range is -25 to +60 °C, storage from -55 to +80 °C. That covers most indoor industrial environments, including unheated warehouses and hot machine cabinets near furnaces.