The S0 frame keeps the footprint compact at 55 mm wide, 85 mm tall, and 101 mm deep — a direct fit into most distribution or motor-control enclosures without extra spacing.
The 11 kW rating at 400 V AC-3 is the headline motor-switching figure — it tells you the contactor can start and stop a 400 V three-phase induction motor up to that shaft power. The AC-4 rating of 15.5 A at 400 V is the one to watch for plugging or jogging duty; if your application cycles the contactor under load, that 15.5 A limit governs, not the AC-3 kW number. The coil draws 5.4 W both on closing and holding, which is a constant DC load on the 24 V supply — no surge beyond the pick-up power. The front face carries IP20 finger protection; the terminals themselves are IP00, meaning the wiring compartment expects enclosure protection from the panel.
If you are evaluating a panel originally built around the smaller 3RT1015-1BB42, the S0 frame of this contactor is physically larger — 55 mm wide versus the S00 frame's 45 mm — so verify DIN-rail space and terminal clearance before assuming a drop-in swap. The screw terminals accept up to 2x 10 mm² or 1x 8 AWG for the main circuit, which covers most motor feeds up to the 11 kW rating.