Panel fit and ratings
The Siemens 5SJ3640-7 is a 4-pole (3P+N) SENTRON miniature circuit breaker from the 5SJ3 design family, rated 40 A with a C tripping characteristic. The C curve means it handles moderate inrush — typical for motor and lighting circuits in commercial and light industrial panels — without nuisance tripping on startup. Breaking capacity is 4.5 kA per both EN 60898 and IEC 60947-2 at 400 V AC. That's the standard for downstream distribution in a sub-board fed by a higher-rated upstream device; it interrupts a fault up to that level without welding the contacts. Occupies 4 modular width units on a DIN rail. Mounting position is any. Installation depth is 70 mm.
Terminal and environment
Solid and stranded conductor range is 0.75 to 25 mm². Sealable terminals support lockout/tagout procedures. Rated for ambient temperatures of -20 to +45 °C, with periodic excursions to +55 °C and 95% humidity. Storage range is -40 to +75 °C. IP20 with connected conductors — suitable for enclosed distribution boards, not open wet areas. Halogen-free and silicon-free construction — important for environments sensitive to corrosive off-gassing (data centers, clean rooms, marine panels). Vibration resistance per IEC 60068-2-6: 50 m/s² at 25–150 Hz.