What it is and where it fits
This Siemens SIRIUS power contactor, order code 3RT2027-1AL20-ZW96, is a size S0 unit that screws or snaps onto 35 mm DIN rail per DIN EN 60715. At 45 mm wide and 97 mm deep, it fits standard panel cutouts for this frame size. The mounting position is flexible — ±180° rotation on a vertical surface, plus ±22.5° tilt forward or backward — handy when you're squeezing it into a tight enclosure corner.
Key ratings and what they mean for the buyer
The contactor accepts solid or stranded wire from 1 to 10 mm² on the main terminals, with screw-type coil connections. That's a practical range for motor circuits up to the S0 frame rating — you won't need adapters for typical 2.5 or 4 mm² power feeds. The coil draws 0.25 A at 50 Hz and 0.28 A at 60 Hz; factor that into your control transformer sizing. Operating temperature spans -25 to +60 °C, storage from -55 to +80 °C. That covers most indoor panel environments without derating, though you'll want to check the thermal curve if the enclosure runs hot. The auxiliary switch is built in — no separate add-on needed for status feedback to the PLC.