The Siemens 5SL6504-7 is a SENTRON miniature circuit breaker (MCB) — a 1P+N, C-curve unit rated 4 A at 230 V AC, with a 6 kA breaking capacity per both EN 60898 and IEC 60947-2.
At 36 mm wide (2 modular units), it occupies the same DIN-rail footprint as a standard single-pole plus neutral MCB. The temperature derating table matters: at 40 °C ambient it's good for 3.76 A, at 55 °C only 3.36 A — so if the panel runs hot, factor that into your load. Mechanical life is 10 000 switching cycles typical.
Panel and integration notes
Mounts in any position on standard DIN rail. Sealable terminals are provided — handy for utility-metering or tamper-proof installations. The 1P+N design switches the line and switches the neutral but does not protect it; the neutral is just switched, not monitored for overcurrent. That's typical for single-phase final circuits where the neutral is solidly bonded.