Siemens 5SY8113-8 — D-Curve MCB for Industrial Circuits
It is rated for 400 V AC (440 V AC single- or multi-phase) and 60 V DC (72 V DC maximum).
The D curve (tripping characteristic class D) means this breaker tolerates inrush currents up to 10–20 times rated current for short durations — exactly what motor starters, transformers, and inductive loads draw on startup. D is deliberately slower on small overcurrents to avoid nuisance trips on high-inrush equipment. The 30 kA breaking capacity at 400 V AC (per IEC 60947-2) tells you this MCB can safely interrupt a fault current up to 30,000 A without welding its contacts or rupturing. That rating is tested under the standard's conditions — it is the maximum fault the breaker can clear and still be reusable after inspection. The UL 1077 supplementary-protector rating of 5 kA is a separate, lower standard for North American panels where the breaker is not the primary service disconnect.
Halogen-free and silicon-free construction. Vibration resistance per IEC 60068-2-6: ±1 mm at 5 to 25 Hz, 50 m/s² at 25 to 150 Hz. The breaker carries IEC/EN 60947-2 and UL 1077 approvals; compliance documentation (RoHS, REACH) is provided by Siemens for the SENTRON series.