The Siemens SIRIUS 3RA2125-1DD23-0AK6 is a non-fused motor starter in a direct starter design — a factory-assembled combination of a contactor and a thermal overload relay in one package, sized as a size S0 load feeder. It ships with the contactor 3RT2023-1AK60 and the link module 3RA2921-1AA00 integrated, so it arrives ready to wire into a motor branch circuit without separate component selection. Rated for AC-3 switching duty up to 690 V, this starter handles motor loads at common line voltages: 1 100 W at 400 V, 1 500 W at 500 V, and 2 hp at 575/600 V. The 690 V ceiling covers most global industrial supply voltages including 400/480/600 V three-phase networks.
This starter is designed for snapping onto 60 mm busbar systems — the standard metric busbar pitch found across European and many Asian panel builds. Mounting position is vertical only, with clearances: 30 mm upward, 10 mm forward, 10 mm downward, 9 mm at the side, and 0 mm backward. That zero backward clearance means it sits flush against the mounting surface, so plan for front-access wiring only. Dimensions are 260 mm height × 45 mm width × 155 mm depth — the width is a single 45 mm module, so it occupies one position on the busbar. The depth of 155 mm includes the contactor and overload assembly; verify enclosure depth before committing the panel layout.