The Siemens SENTRON 5SJ6340-7 is a 3-pole miniature circuit breaker from the 5SJ6 series, rated 40 A at 400 V AC with a C tripping characteristic and a 6 kA breaking capacity per both EN 60898 and IEC 60947-2.
Occupies 3 width units (roughly 54 mm) on a standard DIN rail. Terminals accept solid or stranded conductors from 0.75 mm² up to 25 mm² — covers everything from 2.5 mm² branch circuits up to 10 mm² feeders. Mounting position is unrestricted; the breaker can be installed upside-down or sideways without derating.
Overvoltage category 3, energy limiting class 3. Vibration resistance tested to 50 m/s² at 25–150 Hz and 60 m/s² at 10–150 Hz per IEC 60068-2-6. Halogen-free and silicon-free construction, sealable for tamper-evident installations. Mechanical service life rated at 20 000 switching cycles typical.