It mounts via screw or snap-on onto 35 mm standard mounting rail per DIN EN 50022, fitting a 45 mm wide by 85 mm tall by 91 mm deep footprint — a common panel slot that leaves room for adjacent devices when mounted side-by-side.
That 15.5 A is the real-world limit for plugging or inching a motor; the AC-2 rating of 7.5 kW at 400 V covers slip-ring motor starting, where the current stays lower but the switching frequency is higher. The IP20 front and IP00 terminal protection means it's intended for inside a panel — not washdown, not outdoor without an enclosure.
Main circuit terminals accept solid conductors 2x (0.5...1.5 mm²), 2x (0.75...2.5 mm²), max 2x (0.75...4 mm²) — or stranded 2x (1...2.5 mm²), 2x (2.5...6 mm²), max 2x 10 mm². AWG equivalents are 2x (16...12), 2x (14...10), 1x 8. That's enough cross-section for the 15.5 A AC-4 rating without overtightening; the screw terminals are the standard box-clamp type, so strip length and torque follow the usual SIRIUS practice.