The Siemens 5SL4408-7 is a SENTRON miniature circuit breaker — 4-pole, C-curve, rated 8 A at 30 °C with a 10 kA breaking capacity per EN 60898 and IEC 60947-2. The 400 V AC rated voltage and 440 V AC maximum multi-phase operation suit it for residential and infrastructure distribution boards where a C-curve handles moderate inrush from lighting or small motor loads.
That's the standard choice for general-purpose distribution where you want to ride through motor starting or capacitor switching without nuisance trips. The 10 kA breaking capacity at 400 V AC per EN 60898 means it can safely interrupt a fault current up to that level; the same 10 kA per IEC 60947-2 gives you the rating under the industrial standard. Derate the 8 A at 30 °C to 7.39 A at 40 °C and 6.37 A at 55 °C — if the panel runs hot, the load limit drops. The 72 V DC maximum rating is for the DC side only, not the AC circuit.
Integration notes
Snap-on DIN rail mount, any orientation. Width 72 mm (4 MWU) means it fills four 18 mm slots in a standard enclosure. Halogen-free and silicon-free construction for environments sensitive to outgassing. Touch protection is built in. No neutral conductor switching — the 4th pole is a switched phase, not a switched neutral.