The Schneider Electric C10B44V040 is a ComPacT NSX100B molded-case circuit breaker, 4-pole, with a 40 A electronic MicroLogic 4.2 trip unit. This is the version with integrated earth-leakage protection — the 'V' in the code flags that. It's rated for distribution duty (category A) and carries a 40 kA Icu at 220/240 V AC, 25 kA at 415 V, and 20 kA at 440 V per IEC 60947-2.
Breaking capacity and what it means on your line
At 415 V — common for European industrial distribution — it's still 25 kA. That puts it in the 'B' breaking capacity class for 415 V systems. The MicroLogic 4.2 trip unit gives you L (long-time overload), So (short-time short-circuit with fixed delay), I (instantaneous), and R (earth-leakage) protection curves. The earth-leakage is integrated, so you don't need a separate Vigi module or external RCD — saves a pole space and one wiring step.
Mounts on a backplate — no DIN rail here, so plan for bolt-down or screw-mount in the enclosure. The 4-pole version with the earth-leakage module is the same footprint as the standard 4P, so existing cutouts and busbar layouts carry over. Connection pitch is 35 mm, front-connected both top and bottom. Toggle handle for manual switching, with a rotary IΔn switch for the earth-leakage test/reset.
Durability and environment
Rated for 50,000 mechanical cycles and 30,000 electrical cycles at 440 V at full rated current. That's a solid service life for a distribution MCCB — expect it to outlast the panel refresh cycle in most plants.