What this SIRIUS S0 contactor carries
The Siemens SIRIUS 3RT1024-1BG40-1AA0 is a power contactor in the S0 frame size, rated for 10 A maximum operating current in AC-12 duty — that's the resistive load curve, so it handles heaters, lighting banks, and transformer primaries without derating for inrush. For motor loads, it's specced at 5.5 kW in AC-2 at 400 V (slip-ring motors, wound-rotor applications) and 12.5 A in AC-4 at 400 V (plugging, inching, reversing duty). The holding and closing power of the DC magnet coil is a steady 5.4 W, which keeps the control transformer sizing simple.
Panel fit and wiring reality
Mounts via screw and snap-on onto 35 mm DIN rail per EN 50022 — standard panel integration. The 45 mm width and 101 mm depth mean it fits a standard S0 footprint; side-by-side mounting is allowed with 6 mm spacing between units. Main circuit terminals are screw-type, accepting 2x (0.75... 4 mm²) solid or 2x (1... 2.5 mm²) stranded, with a max of 2x 10 mm². Front face carries IP20 protection — safe for finger contact in an open panel; the terminal area itself is IP00, so live parts are exposed until the gland plate is on. Operating temperature range is -25 to +60 °C, with derating above 40 °C.
Coordination and protection
For Type 2 coordination (no welding after a short circuit), the required upstream fuse is gL/gG 25 A. For Type 1 coordination (welding allowed, but no fire risk), it's gL/gG 63 A. The contactor is rated for a pollution degree of 3 (conductive pollution, typical in industrial enclosures), and maximum operating altitude is 2 000 m without derating.