What the ratings mean for fit
The 5SY6406-8CC is a SENTRON miniature circuit breaker with a D tripping characteristic, 4 poles, rated 6 A at 400 V AC. The D-curve means it tolerates high inrush currents — typically 10–20× the rated current for short durations — so it's the right choice for motor circuits, transformers, or other inductive loads that draw a heavy startup surge without tripping on the magnetic release. The 6 kA breaking capacity per EN 60898 covers most industrial distribution panels; if your fault current exceeds that, you'll need an upstream current-limiting device. The 4-pole design switches all phases plus the neutral (though neutral is not switched separately — it's a solid neutral through the breaker).
Deployment context
Snaps onto a DIN rail via the quick-assembly system, occupying 4 modular width units (72 mm wide). Mounting position is any orientation, which simplifies panel layout. The IP20 rating (with connected conductors) means it's intended for enclosed distribution boards — not for washdown or outdoor exposure. Pollution degree 3 and overvoltage category III suit it for fixed industrial installations where conductive dust or transient surges are present.
Approvals and compliance
Rated breaking capacity is 6 kA per EN 60898 and 5 kA per UL 1077 / CSA C22.2 No.235. The breaker is halogen-free and silicon-free, which matters for panels in clean-room or corrosive environments. Sealable terminals allow lockout/tagout compliance. Vibration resistance per IEC 60068-2-6 covers ±1 mm at 5–25 Hz and 50 m/s² at 25–150 Hz — enough for machine-mounted panels.