The Siemens SENTRON 5SY4163-7KK11 is a 1-pole miniature circuit breaker rated 63 A with a C tripping characteristic, built for branch-circuit protection in industrial and railway applications. It breaks 10 kA per DIN EN 60898-1 and 15 kA per IEC 60947-2 — the higher figure matters when the available fault current at the panel exceeds 10 kA, so check your SCCR before committing the BOM line. The 18 mm width (1 modular unit) and 76 mm depth let it slot into standard DIN-rail enclosures without crowding adjacent breakers. Mounting position is any orientation, and the quick-assembly fastening system clips onto the rail without tools.
Thermal derating and ambient limits
The 63 A rating holds at 35 °C ambient. At 40 °C it derates to 59.16 A, at 50 °C to 55.06 A, and at 60 °C to 50.65 A. If the panel internal temperature runs hot — common in sealed railway enclosures or crowded cabinets — use the 50 °C figure for sizing, not the 35 °C headline. Operating range spans -40 °C to 75 °C, so it handles both cold-start in unheated cabinets and sustained heat near transformers or drives.
Sourcing and fit decision
For a BOM line that previously specified the 5SY4140-7 (40 A version) or the 5SL6016-7KL (B-curve 16 A), the 5SY4163-7KK11 drops into the same 18 mm DIN footprint with the same 70 mm installation depth and combined terminal layout — no rewiring or enclosure change needed, just verify the 63 A rating matches the load and the C-curve magnetic trip suits the inrush.