The Siemens SIRIUS 3RA2120-1JD24-0FB4 is a direct online starter — a pre-assembled combination of a contactor and a circuit-breaker in one package, sized S0 for motor loads up to 10 A in AC-3 duty at 400 V. It ships with the 3RT2024-1FB40 contactor and the 3RA2921-1BA00 link module already integrated, so it arrives as a single unit ready to snap onto a 60 mm busbar system. The 24 VDC coil (24... 24 V rated value) means it fits standard control-voltage architectures common in PLC-driven panels.
Rated operational voltage maxes out at 690 V AC-3, so it's suitable for 400 V line supplies common in industrial panels across Europe. The 45 mm width and 165 mm depth keep the panel footprint tight — it occupies one standard S0-width slot on the busbar, leaving room for adjacent feeders.
Fastens by snapping onto 60 mm busbar systems — no separate DIN-rail adapter needed. Mounting position is vertical only, with 50 mm clearance upward, 20 mm forward, 20 mm at the side, and 10 mm downward for airflow and arc containment. The supplied link module handles the internal connection between the contactor and the circuit-breaker section.