What this MCB carries and where it fits
The Siemens 5SY8163-7 is a 1-pole SENTRON miniature circuit breaker rated 63 A with a C tripping characteristic. The C-curve means it trips at 5 to 10 times rated current — the standard choice for motor circuits, transformers, and general industrial loads where moderate inrush is expected. The 25 kA breaking capacity per IEC 60947-2 tells you it can safely interrupt a fault up to that level without upstream devices needing to clear it first. Same part, different passport: this is the current-production version, not an NRND or EOL line. At 18 mm wide (one modular unit), it snaps onto standard DIN rail in any orientation. The 76 mm depth leaves clearance for wiring in shallow enclosures. Rated IP20 with connected conductors — fine for enclosed panels, not for wet washdown zones.
Breaking capacity and coordination reality
The 25 kA at 400 V AC per IEC 60947-2 is the headline fault rating. For UL and CSA applications, the same part carries 5 kA — a different standard, not a downgrade. Thermal derating is published: full 63 A up to 45 °C, then 61.05 A at 50 °C, 59.03 A at 55 °C. Ambient conditions up to 75 °C are allowed with the appropriate humidity derating per the spec table. For a panel running warm near a drive or transformer, check the 50 °C column before assuming full rating.
Compliance and documentation
The 5SY8163-7 carries IEC 60947-2, UL 1077, and CSA C22.2 No. 235 approvals. It is halogen-free and silicon-free — relevant for clean-room or high-reliability environments where outgassing matters. The sealable design and touch protection features support panel-lockout procedures during maintenance.