What's in the box — the 5SY4114-8CV
The Siemens 5SY4114-8CV is a 1-pole miniature circuit breaker with a D0.3 tripping characteristic and a rated short-circuit breaking capacity of 15 kA at 230/400 V AC. That Icu figure — 15 kA — tells you it can safely interrupt a fault current up to that level without welding its contacts or cascading upstream. The D curve means it's built for loads with a high inrush, think small transformers or motor starters, where the magnetic trip needs to ride out the starting surge. It's a panel-mount DIN-rail unit, standard 1-module width, so it slots straight into a distribution board alongside other 5SY4 breakers.