For BOM-line commitment, the 15 kA Icu at 400 V and C63 rating are the fit-determining parameters — confirm the prospective fault level at the installation point and the load type (C-curve suits inductive or motor-starting loads with moderate inrush).
Panel integration
The 3-pole footprint occupies three modular-width units (each 17.5 mm) in the distribution board. Rated for 400 V phase-to-phase, so it directly replaces a 3-pole MCB in a three-phase sub-feed without needing a neutral pole.