The Schneider Electric EZC400N44250 is a 4-pole molded case circuit breaker from the EasyPact EZC400N series, rated 400 A at 40 °C. It uses a thermal-magnetic TM-D trip unit for combined overload and short-circuit protection. The breaking capacity hits 36 kA Icu at 440 V AC 50/60 Hz per IEC 60947-2, which means it can safely interrupt a fault current up to that level without welding contacts or cascading upstream — a key figure for panel coordination studies. With a utilisation category of A, it is not intended for frequent switching under load; this is a distribution breaker, not a motor-starter isolation device.
Overall dimensions: 255 mm high, 185 mm wide, 140 mm deep.
The 36 kA Icu at 440 V AC is the ultimate short-circuit breaking capacity — the breaker can interrupt one major fault and still be functional afterward (though you would replace it). The magnetic trip is fixed at 5000 A, so it clears high-impedance faults fast. The TM-D trip unit has a thermal element that tracks load current; at 250 A and 50 °C ambient, the trip curve shifts — account for this in high-temp enclosures.