The Siemens 5SL6663-7MB is a SENTRON miniature circuit breaker — 4-pole (3P+N), 63 A, C-curve, rated 400 V AC with a 6 kA breaking capacity per both EN 60898 and IEC 60947-2.
The 6 kA breaking capacity is standard for domestic and light commercial installations — adequate for most utility-side fault levels, but verify against your point-of-supply SCCR if feeding from a transformer. The C-curve characteristic suits loads with moderate inrush: small motors, pumps, compressors, and groups of lighting ballasts.
Snap-on DIN-rail mounting in any position. The 72 mm width (4 MW) and 76 mm depth match standard SENTRON panel cutouts. Sealable terminals allow lockout/tagout compliance.
Halogen-free and silicon-free construction. Energy limitation class 3 — meaning it limits let-through energy well enough for most downstream equipment protection.