It clears faults up to 50 kA at 400 VAC — enough for high-fault-capacity mains feeders or sub-distribution where upstream breakers are rated similarly.
The 16 A thermal element protects the cable and load against sustained overload. At 230 VAC single-phase (the common residential/commercial line), the 50 kA interrupting rating is far above typical available fault current; at 400 VAC three-phase it still holds 50 kA, covering most industrial panelboard applications.