It's not a general-purpose feeder breaker; the magnetic short-circuit trip responds at 520 A instantaneous, sized to coordinate with a downstream contactor's making and breaking capacity. Rated operational current is 40 A at AC-3 duty (400 V), so it handles motor starting currents up to that level.
The S3 frame size is the largest in the SIRIUS 3RV5 family; width is 70 mm, depth 174 mm, height 165 mm. Clearance requirements: 50 mm above and below, 167 mm forward, 30 mm to the side. Main circuit connections are screw-type box terminals on top and bottom, accepting up to 70 mm² solid or stranded (or 2/0 AWG). Terminal torque spec is 4 to 6 N·m. This is a panel-mount part, not a plug-in base; wire it direct.