What this SIRIUS contactor is and what it does
The Siemens SIRIUS 3RT1025-1AG20-ZW96 is a power contactor in the S0 frame size, designed for switching motor loads in industrial control panels. It mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 50022, with a 45 mm width that fits standard panel layouts. Rated for AC-3 duty at 11 kW on a 690 V supply and 10 kW at 500 V, this contactor handles the full-load current of motors in that power band. The AC-2 rating at 400 V is 7.5 kW, and the AC-4 rating at 400 V is 15.5 A — the latter governs reversing or inching applications where the contactor makes and breaks the motor current under load.
Mounting and integration into a panel
Snap-on mounting onto 35 mm DIN rail per DIN EN 50022, or screw-mount if preferred. Side-by-side mounting is permitted, with a 6 mm clearance to adjacent devices on the side. The front face carries an IP20 rating — safe for finger-probe access in a live panel — while the terminal area is IP00, meaning the connection points are exposed and require enclosure-level protection. Operating temperature range is -25 to +60 °C, with a maximum operating altitude of 2 000 m. Pollution degree 3 means it tolerates conductive dust and humidity typical of industrial environments without conformal coating.
Wiring and termination
Main current circuit uses screw-type terminals. Solid conductors accepted: 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), and max 2x (0.75 to 4 mm²). Stranded conductors: 2x (1 to 2.5 mm²), 2x (2.5 to 6 mm²), and max 2x 10 mm². AWG equivalents for main contacts: 2x (16 to 12), 2x (14 to 10), and 1x 8.
Short-circuit coordination and protection
For Type 2 coordination (no damage to the contactor after a fault), the required upstream fuse is gL/gG 25 A. For Type 1 coordination (contactor may be damaged but no fire or shock hazard), the fuse rating is gL/gG 63 A. These values define the maximum fuse size for the respective coordination type.