Ratings that matter for panel fit
The 5SL4440-8: The 40 A rating holds at 30 °C ambient; at 40 °C it derates to 37.89 A, and at 55 °C to 34.47 A. If the panel runs hot — say, a crowded enclosure with other breakers — factor that derating into the circuit design. The 10 kA SCCR per EN 60898 and IEC 60947-2 means it safely interrupts faults up to that level without upstream cascading. Overvoltage category III (distribution-level) and pollution degree 2 suit it for fixed installations inside a panel.
Mounting and integration
Snap-on mounting to DIN rail, any position. Occupies 4 modular width units (72 mm wide, 90 mm tall, 76 mm deep). IP20 with connected conductors — protected against finger contact, not washdown. Sealable, halogen-free, silicon-free. Neutral conductor switching is not integrated; the 4-pole unit switches all four poles, so plan for a separate neutral bar if the application requires it.