The Siemens 5SY4363-8CV is a 3-pole miniature circuit breaker (MCB) with a D63 tripping characteristic and a rated short-circuit breaking capacity (Icu) of 15 kA at 400 V AC.
For BOM-line commitment, the 15 kA Icu at 400 V and D63 curve are the fit-critical specs — confirm these match your panel's fault level and load type before ordering.
Typical deployment includes motor control centers, pump panels, conveyor drives, and transformer primary protection where the D curve matches the inrush profile.