What this MCB does on the panel
The Siemens 5SL4313-8CC is a 3-pole miniature circuit breaker rated 13A at 400V with a 10kA breaking capacity, D-curve trip characteristic. The 10kA breaking capacity at 400V is the standard residential and light-commercial SCCR for this class; it clears a hard fault without upstream fuse coordination in most panelboards. Mounts on standard DIN rail in the distribution board.
The D-curve magnetic trip operates between 10× and 20× In (130–260A instantaneous), so a motor drawing 8A running with a 50A locked-rotor surge won't trip the breaker on start. The 400V rating covers 3-phase line-to-line voltage; the 10kA Icn is the rated short-circuit capacity per IEC 60898. For a 3-pole config, you're protecting a 3-phase load or three independent single-phase circuits with a common handle.