That means its overload curve and short-circuit release are tuned to handle transformer inrush without nuisance tripping — a detail that matters when you're protecting a dry-type or distribution transformer on a 400 V bus. At 690 V it still clears 4 kA. That SCCR lets this breaker sit upstream of smaller branch devices without worrying about cascading failure during a bolted fault. If your transformer secondary feeds an ungrounded delta or you need GF protection, you'll add an external ground-fault relay or specify a different variant.
Termination & Environment
Main current circuit connections use screw-type terminals, accepting 2× (0.75 to 2.5 mm²) solid or stranded, or 2× 4 mm². The M3 screw is standard for this frame size; torque to the Siemens spec during panel build. That covers most indoor panel environments — no special derating needed for a typical MCC room or cabinet. The fuse backup requirements are specified: gL/gG 50 A at 400 V, 40 A at 500 V, and 40 A at 690 V — coordinate your upstream fuse selection accordingly.