The Siemens SENTRON 5SL4540-6 is a 1P+N miniature circuit breaker with a B tripping characteristic, rated at 40 A and 230 V AC. It provides a 10 kA breaking capacity per both EN 60898 and IEC 60947-2, making it suitable for residential and light commercial distribution boards where short-circuit levels stay under that threshold. The B-curve trips between 3 and 5 times rated current — designed for resistive and general-purpose loads where inrush is modest. The 1P+N configuration switches the line and switches the neutral, with neutral conductor switching built in.
Ratings and derating
At 30 °C the breaker carries the full 40 A. At 40 °C that drops to 37.89 A, at 45 °C to 36.8 A, and at 55 °C to 34.47 A. If the panel ambient runs hot — say a crowded enclosure near a process line — the derated figure governs the load you can protect. The 2-module-width body (36 mm wide, 90 mm tall, 76 mm deep) snaps onto standard DIN rail. Mounting position is unrestricted. IP20 with connected conductors means it's protected against finger contact but not against moisture — keep it inside a rated enclosure.