Busbar-mount reversing starter, 22 A AC-3
The Siemens 3RA2220-4CH27-0AP0 is a SIRIUS reversing starter in Size S0, designed to snap directly onto 60 mm busbar systems — no DIN rail adapter needed. It ships as a factory-assembled unit with the contactor (3RT2027-2AP00) and link module (3RA2921-2AA00) already integrated, saving panel build time.
Dimensions and panel fit
The unit measures 260 mm high × 90 mm wide × 165 mm deep. Mounting is vertical only, with clearance requirements: 50 mm upwards, 32 mm forwards, 10 mm downwards, 10 mm at the side, and 0 mm backwards — the back face sits flush against the busbar. The S0 feeder size matches the standard S0 circuit-breaker footprint, so upstream protection coordinates without adapters.
Operating temperature range is -20 to +60 °C, storage and transport from -50 to +80 °C.