The Siemens 5SY4610-8CV is a miniature circuit breaker (MCB) with a D10 tripping characteristic, 3-pole plus neutral configuration, and a rated ultimate breaking capacity (Icu) of 15 kA at 400 V AC. That 15 kA figure is the maximum fault current the breaker can safely interrupt without welding its contacts or rupturing the enclosure — critical for installations where the prospective short-circuit current at the panel exceeds the standard 6 kA or 10 kA class. The D10 curve means the thermal-magnetic trip holds through motor inrush (5–10× rated current) and is sized for loads like small motors, transformers, or discharge lamps where the start-up surge would nuisance-trip a B or C curve.
The 15 kA Icu at 400 V gives headroom for transformer-fed supplies or industrial networks where fault levels are higher than a typical residential 6 kA installation.