The Schneider Electric EasyPact EZC400N3320N is a 3-pole moulded-case circuit breaker rated 400 A at 40 °C ambient, with a TM-D thermal-magnetic trip unit set for 320 A at 50 °C. The 320 A figure at elevated temperature governs real-world fit in a non-air-conditioned enclosure. Breaking capacity hits 36 kA Icu at 440 V AC (50/60 Hz) per IEC 60947-2, with 40 kA available at 220/230 V. The N breaking-capacity code places it between standard and high-performance in the EasyPact range — adequate for most distribution panels downstream of a transformer, but verify against your prospective fault current at the mounting point. Magnetic trip is fixed at 4000 A — no adjustment range on the TM-D unit. That means the instantaneous pickup is 10× In (based on the 400 A frame), so it clears bolted faults fast but may coordinate differently with downstream devices than an adjustable electronic trip would. For motor branch circuits or feeders with high inrush, confirm the magnetic setting doesn't nuisance-trip on starting current.
Fixed-mount, backplate installation — no DIN-rail adapter on this frame. The toggle operator and positive contact indicator give visual confirmation of breaker state without opening the door. IP20 finger-safe protection on the front face; IK07 impact resistance means it handles incidental tool contact during panel work.
Electrical endurance is 4000 cycles at 415 V AC under Category A (no intentional maintenance), mechanical endurance 10,000 cycles. Neutral protection is not provided (3-pole, 3-phase only). For applications requiring ground-fault or neutral protection, you'd need a different frame or an external relay.