SIRIUS S2 power contactor — fit and ratings
The Siemens 3RT1035-1AL20-ZW95 is a SIRIUS S2-frame power contactor rated for 22 kW at 500 V in AC-3 duty — the motor-switching category that governs most induction-motor starts and stops in industrial panels. The S2 frame size (55 mm wide, 112 mm tall, 115 mm deep) fits the standard 35 mm DIN rail per EN 50022, with screw-and-snap-on mounting. Screw-type terminals on the main current circuit accept solid conductors from 0.5 to 4 mm² (two per clamp) and stranded up to 25 mm², covering typical motor feeder sizes up to 22 kW. The 22 kW at 500 V AC-3 rating is the headline selection figure; at 400 V AC-2 the contactor is rated 18.5 kW. Operating temperature range is -25 to +60 °C, with storage from -55 to +80 °C. The front of the device carries IP20 protection; the terminal area is IP00, meaning the panel builder must provide finger-safe shrouding or enclosure clearance around the wiring zone.
Integration notes
Mounts via screw and snap-on onto 35 mm DIN rail per EN 50022. Side-by-side mounting is permitted, so multiple contactors can be ganged without spacing gaps — useful for compact motor control centers. The S2 width of 55 mm leaves room for auxiliary contact blocks on the front; the IP20 front cover allows safe access for commissioning with the panel door open. Conductor termination: solid wires 2x (0.5...1.5 mm²) or 2x (0.75...2.5 mm²) per clamp, max 2x (0.75...4 mm²); stranded 2x (0.75...25 mm²). The wide stranded range accommodates both control wiring (1.5 mm²) and motor power cables (up to 25 mm²) without needing adapter lugs. Pollution degree 3 means the contactor is rated for industrial environments with conductive dust or occasional condensation — no additional conformal coating required for typical panel conditions.