The Siemens 5SL6104-7YA is a 1-pole miniature circuit breaker (MCB) rated 4 A with a C-trip curve, designed for 230/400 V AC systems and a 6 kA breaking capacity per IEC 60898. At 4 A it is sized for branch circuits feeding a few contactor coils, a small PLC power supply, or similar low-current loads in a distribution board.
Panel integration
The 1-pole width (1 module ~18 mm) keeps panel density high.