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.
Integration notes
Side-by-side mounting is permitted, so multiple contactors can be ganged without spacing gaps — useful for compact motor control centers. 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.