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 1P+N configuration switches the line and switches the neutral, with neutral conductor switching built in.
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. The 2-module-width body (36 mm wide, 90 mm tall, 76 mm deep) snaps onto standard DIN rail. Mounting position is unrestricted.