What it is and the ratings that matter for fit
The 5SY4404-7: Temperature derating is specified from 35 °C upward: 3.81 A at 40 °C, stepping down to 3.39 A at 60 °C. If the breaker sits in a warm enclosure or near other heat sources, use the 40 °C or 50 °C column rather than the 35 °C rating to avoid nuisance tripping.
Mounting and panel footprint
The 5SY4404-7 occupies 4 modular width units (72 mm wide) on a DIN rail, with a depth of 76 mm (70 mm installation depth). The quick-assembly system allows snap-on mounting and removal without tools. Combined terminals are provided at both top and bottom, accepting conductors up to the cross-section supported by the terminal design. Mounting position is unrestricted, and the enclosure is sealable. IP20 is achieved only with connected conductors — the front face is finger-safe, but the terminals require conductors to maintain the protection rating. Pollution degree 3 and overvoltage category III make it suitable for fixed installations within industrial panels where conductive pollution and transient overvoltages are expected.
Lifecycle and sourcing posture
The part is halogen-free and silicon-free, which may simplify compliance declarations for certain industry segments (semiconductor, medical, rail) where material restrictions are enforced.