Siemens SENTRON 5SY6040-7KL is a 1-pole+N miniature circuit breaker with C-curve tripping characteristic, rated 40 A at 230 V AC and a breaking capacity of 6 kA per EN 60898. It occupies a single 18 mm width unit on standard DIN rail, with a depth of 76 mm and an installation depth of 70 mm — slots into the same panel footprint as any 1P+N SENTRON 5SY6 series breaker.
Screw-type terminals accept solid or stranded conductors from 0.75 to 16 mm², with a tightening torque of 2 to 2.5 N·m (17.7 to 22.1 lbf·in). That 16 mm² top end is enough for a 40 A feed conductor without needing a ferrule or pin terminal — just strip and torque. Both top and bottom terminals are non-combined (separate entry per conductor), and the breaker is sealable — useful for installations where the utility or inspector wants to lock the setting after commissioning.
Rated for ambient temperatures from -25 to +45 °C during operation, and -40 to +75 °C in storage. Vibration-resistant per IEC 60068-2-6, and mountable in any position, which simplifies panel layout when space is tight. Halogen-free and silicon-free construction, so it won't outgas corrosive compounds in a sealed enclosure near sensitive electronics or in clean-room adjacent panels.
The neutral conductor is switched (1P+N), and the supply cord position is any — no fixed line/load orientation on the neutral pole. Touch protection is integrated on the terminals. Mechanical service life is 4 000 switching cycles typical — adequate for a distribution breaker that sees infrequent manual operation, not a daily-switched load controller.