What it is and what it does
The Siemens SENTRON 5SY8463-8 is a 4-pole miniature circuit breaker with a D tripping characteristic, designed for high-inrush loads like motor circuits and transformers. It carries a 20 kA breaking capacity at 400 V AC per IEC 60947-2 and 5 kA per UL 1077, with a DC rating of 15 kA at 60 V. Rated operating voltage is 400 V AC (440 V max multi-phase or single-phase), and DC rated voltage is 60 V (72 V max). It operates at 50/60 Hz and is rated for pollution degree 3, overvoltage category III.
D-curve and breaking capacity — the so-what
The D characteristic means the breaker trips at 10–20× rated current, which suits loads with high starting surges — motor starters, welding equipment, or transformer primaries — without nuisance trips. The 20 kA SCCR at 400 V AC means it can safely interrupt a fault current up to that level, protecting downstream wiring and devices. At DC, the 15 kA rating at 60 V covers common industrial DC bus applications. The 5 kA UL 1077 rating makes it acceptable for UL-listed panels in North American installations.
Mounting and integration
Snaps onto DIN rail via a quick-assembly system, any mounting position. Occupies 4 modular width units (72 mm wide). Depth is 76 mm (70 mm installation depth). IP20 with connected conductors — suitable for enclosed panel use, not washdown. Combined terminals on top and bottom simplify wiring. Sealable, halogen-free, silicon-free — meets clean-room and low-smoke requirements. Vibration resistance per IEC 60068-2-6: ±1 mm at 5–25 Hz, 50 m/s² at 25–150 Hz.