The EZC400N3250 is a 3-pole EasyPact EZC400N circuit breaker from Schneider Electric, rated 400 A at 40 °C with a thermal-magnetic TM-D trip unit.
This breaker carries a 36 kA Icu (ultimate breaking capacity) at 440 V AC, 50/60 Hz, per IEC 60947-2. At 220/230 V AC it bumps to 40 kA Icu. The 'N' in the part number tells you it's the standard breaking capacity level in the EZC400 family; there's also an 'H' (high) and 'S' (superior) variant if you need more.
The TM-D trip unit is thermal-magnetic — a bimetal strip handles overloads (slow response to sustained overcurrent), and a solenoid handles short-circuits (instantaneous trip). The magnetic trip is factory-set to 3500 A, which is about 8.75x the 400 A frame rating. That's a typical fixed magnetic setting for distribution breakers; it avoids nuisance tripping on motor inrush but clears a hard fault fast. Overload protection is adjustable via the TM-D rating plug — this unit ships with a 250 A plug at 50 °C, so if your ambient in the panel runs hot, the breaker derates accordingly. No earth-leakage module built in; you add an external Vigi unit if you need ground-fault protection.
Mounts fixed to a backplate — no DIN rail here. Dimensions are 255 mm high, 185 mm wide, 140 mm deep. The 44 mm pole pitch is standard for this class of molded-case breaker, so bus-bar kits and lug kits from the EasyPac range fit without surprises. Front-connect top and bottom means you land cables straight in without reaching around the back. IP20 finger-safe protection on the front; IK07 impact rating means it shrugs off a tool drop or a panel door slam. Pollution degree 3 per IEC 60947 — that's conductive pollution (like dust with moisture), so it's fine in most industrial enclosures but not sealed for washdown.
Meets EN/IEC 60947-1 and 60947-2 (low-voltage switchgear and controlgear), plus GB/T 14048.2 (Chinese national standard) and JIS C8201-2-2 (Japanese industrial standard). Utilisation category A means it's not intended for frequent switching under load; that's for the contactor, not the breaker.