What this MCB does on the rail
The Siemens SENTRON 5SY5415-7 is a 4-pole miniature circuit breaker with a C-curve trip characteristic, rated at 1.6 A for AC circuits and carrying a 10 kA breaking capacity at 230/400 V AC per EN 60898, and also 10 kA at 880 V DC per EN 60898-2. Four poles let it switch all phases plus neutral in a single module, saving rail space over ganging singles. Rated current derates with ambient temperature: 1.6 A at 35 °C, 1.54 A at 40 °C, 1.5 A at 45 °C, 1.47 A at 50 °C, 1.44 A at 55 °C, and 1.4 A at 60 °C.
Touch protection is built in — no live parts exposed with conductors connected.