What this SIRIUS 3RA2 starter packs
The Siemens 3RA2125-1CA23-0AP6 is a SIRIUS non-fused direct motor starter — a combined contactor and thermal overload relay in one S0-size package, designed for small motor loads like pumps, fans, and conveyors. The unit snaps onto a DIN rail or can be screw-mounted with an additional push-in lug, and mounts vertically — no special bracket needed for most panels.
Width is 45 mm, depth 97.1 mm, height 193.1 mm — the S0 feeder footprint is standard across the SIRIUS 3RA2 line, so it drops into existing cutouts without rework. Clearance requirements: 30 mm upward, 10 mm forward, 10 mm downward, 9 mm at the side, and 0 mm backward — tight panel layouts can use the zero-backward clearance to stack against the backplane. The supplied contactor is 3RT2023-1AP60 and the link module is 3RA2921-1AA00 — these are matched components, so no separate ordering for the contactor and overload pair.