What the ratings mean for fit
The Siemens SENTRON 5SL6140-8CC is a 1-pole miniature circuit breaker with a D tripping characteristic, rated 40 A at 30 °C and 230/400 V AC. The D-curve means it tolerates inrush currents 10–20 times the rated current — designed for loads with high starting surges like small motors, transformers, or solenoid banks where a B or C curve would nuisance-trip. The 6 kA breaking capacity per EN 60898 is the standard for residential and light commercial distribution boards; it safely interrupts a short-circuit fault up to 6,000 A without welding the contacts or cascading to the upstream device. At 40 °C ambient the continuous rating derates to 36.88 A, so a panel running warm needs to account for that headroom.
Deployment context
This breaker snaps onto a standard 35 mm DIN rail and occupies one modular width unit (18 mm). The IP20 rating with connected conductors means it's protected against finger contact but not moisture — install inside a panel or enclosure, not in a washdown zone. Mounting position is unrestricted, so it can go sideways or upside-down in a tight cabinet without derating the thermal trip. Vibration resistance tested to 50 m/s² at 25–150 Hz per IEC 60068-2-6, which covers most industrial panel environments including near conveyor drives.