The Siemens 5SL4363-8 is a SENTRON miniature circuit breaker — 3-pole, 63 A rated at 400 V AC, with a D tripping curve and 10 kA breaking capacity per both EN 60898 and IEC 60947-2. That D curve means it's built for high inrush loads: motor starters, transformers, discharge lighting. The 10 kA SCCR at 400 V tells you it can clear a fault up to that level without upstream devices needing to trip — a real consideration in panel coordination studies.
What the ratings mean for fit
The 63 A rating is at 30 °C ambient. At 40 °C it derates to 60.45 A; at 45 °C to 57.96 A; at 55 °C to 56.41 A. If your panel runs hot — and most do — size the load side accordingly. The D characteristic (10–20× In magnetic trip) handles motor starting without nuisance trips, but it also means the breaker won't clear a low-level overload as fast as a B or C curve would. That's by design: you trade selectivity for inrush tolerance. Power loss is 5 W per pole at rated current in hot operating state.
Mounting and integration
Snaps onto DIN rail in any mounting position. Occupies 3 modular width units (54 mm total width). Depth is 76 mm; installation depth 70 mm. IP20 with connected conductors — fine inside a panel, not for wet or dusty locations. Sealable, halogen-free, silicon-free. Overvoltage category III, pollution degree 2.