The Siemens 5SY7415-8 is a 4-pole SENTRON miniature circuit breaker with a D tripping characteristic and a 1.6 A rated current. It's designed for branch-circuit protection in industrial control panels, particularly where high inrush currents from motor starters or transformers are expected — the D curve allows a brief overload surge without nuisance tripping, then clears hard faults fast. Rated 400 V AC (overvoltage category III) and breaking 15 kA per EN 60898 or 50 kA per IEC 60947-2, this MCB handles the fault-current levels typical of a 400 V distribution board. The 50 kA rating under IEC 60947-2 means it's tested for industrial-grade fault interruption, not just residential service. Mounts on a DIN rail via the quick-assembly system in any position, with a 4-module width (72 mm) and 70 mm installation depth. The IP20 enclosure (with connected conductors) is standard for enclosed panel mounting — not for wet or outdoor use without a cabinet.
Key ratings and what they mean for fit
The D tripping characteristic means the magnetic trip operates at 10–20× rated current — about 16–32 A for this 1.6 A unit. That's the right choice for circuits feeding motor starters, solenoid banks, or small transformers where the inrush peak exceeds the 5–10× range of a C-curve breaker. If your load is purely resistive or has a low inrush, a B or C curve would trip faster on a fault; the D curve trades some speed for ride-through on startup. Breaking capacity: 15 kA at 400 V AC per EN 60898 (the residential/light-commercial standard) and 50 kA per IEC 60947-2 (the industrial standard). The 50 kA figure is the one that matters for most industrial panels — it tells you this breaker can safely interrupt a fault up to 50,000 A without welding its contacts or rupturing the case. At 440 V AC with multi-phase operation, the rating holds at the same 50 kA per IEC 60947-2. Rated for a wide ambient range: -40 °C to +75 °C, with humidity limits that derate above 55 °C. That covers unheated enclosures in cold climates and hot panel interiors near transformers or drives.
Panel integration notes
Four modules wide (72 mm) on a DIN rail, with a 70 mm installation depth and 76 mm overall depth. The quick-assembly mounting system snaps onto the rail without tools. Combined top and bottom terminals accept the incoming and outgoing conductors on the same side — useful for daisy-chaining busbars or looping through multiple breakers in a distribution block. Halogen-free and silicon-free construction matters for panels in clean-room or semiconductor-adjacent environments where outgassing can contaminate optics or sensitive surfaces. The sealable feature allows locking the toggle in the off position for lockout/tagout compliance.