What this MCB is and what it does
The Siemens 5SJ4111-7HG40 is a 1-pole SENTRON miniature circuit breaker (MCB) with a C-curve tripping characteristic, designed for branch-circuit protection in industrial control panels and distribution boards. It snaps onto a standard 35 mm DIN rail and occupies one modular width (18 mm), so it fits the usual 18 mm-per-pole grid in a panel.
Key ratings and what they mean for fit
Rated at 10 kA breaking capacity per EN 60898 and 15 kA per IEC 60947-2 at 400 V AC. The C-curve (magnetic trip between 5× and 10× In) is the standard choice for moderate inrush loads like small motors, contactor coils, and lighting — it avoids nuisance trips on startup while still clearing a hard fault. The 15 kA rating under IEC 60947-2 is the one that matters for industrial panel SCCR calculations; 10 kA under EN 60898 covers residential and light commercial. Rated insulation voltage (Ui) is 440 V AC, so the breaker is suitable for 400 V line-to-line systems with margin. DC rating is 60 V maximum, which limits its use on DC circuits to single-pole switching at that voltage — fine for control-voltage busses or small DC loads, not for higher-voltage DC strings. Pollution degree 3 and overvoltage category 3 mean it's rated for the industrial environment: conductive pollution can occur, and it handles transient overvoltages typical of fixed-installation distribution.
Mounting and integration
IP20 with connected conductors, IP40 in the handle range — standard for enclosed panel mounting; not rated for washdown or outdoor exposure without an enclosure. Ambient temperature range -40 °C to 75 °C covers most industrial environments, including cold storage and hot machine cabinets. Vibration resistance is specified at 50 m/s² over 25–150 Hz and 60 m/s² at 35 Hz (4 s), which is adequate for general industrial machinery but not for extreme shock loads.