SIRIUS S0 DOL starter — 12 A AC-3, snaps onto 60 mm busbars
The Siemens 3RA2125-1KH24-0FB4 is a SIRIUS direct on-line starter in size S0, rated 12 A at 400 V AC-3 — the motor-switching current that governs real-world induction-motor starts up to 5.5 kW at 400 V. It snaps onto 60 mm busbar systems, so panel integration is a clip-and-wire job — no DIN-rail adapter needed.
The starter body is 165 mm deep, 45 mm wide, and 260 mm tall. Clearance requirements: 50 mm upward, 20 mm forward, 20 mm at the sides, 10 mm downward — no backward clearance needed. That fits tight panels if you plan the gland plate entry; the vertical mounting position is mandatory.