The ENW13227 is a 4P EasyPact NW circuit breaker from Schneider Electric, rated 1000 A at 40 °C and built to IEC 60947-2. The 66 kA Icu at 220...440 V AC 50/60 Hz is the maximum short-circuit current it can safely interrupt once — that's the ultimate breaking capacity, and it's the number that governs fault-clearing at the main distribution point. The 55 kA Ics (service breaking capacity) tells you it can clear that level repeatedly without needing replacement, which matters for a main breaker where faults are rare but the breaker stays in service. The 50 kA Icw for 1 second is the short-time withstand rating — the breaker can hold that current closed for a full second while downstream devices clear a fault, which is the coordination window you design selective tripping around. Rated insulation voltage is 1000 V AC, impulse withstand 12 kV — that's the clearance and creepage design for a 440 V operational voltage, giving a solid safety margin on a 400 V distribution bus. The IP30 enclosure keeps hands and tools out but expects panel-side protection from liquid ingress. Mechanical durability is 20000 cycles with maintenance, 10000 without — that's a lifetime figure for a fixed-mount distribution breaker that sees infrequent switching. Electrical durability is 5000 cycles at 440 V without maintenance, Category B, which aligns with its role as a distribution breaker rather than a motor-switching device.
Fixed mounting on a rail base plate, rear-connected. The 346 mm width by 301 mm height by 196 mm depth footprint fits standard low-voltage switchgear cubicles; the 70 mm connection pitch without spreader matches common busbar drilling patterns. Neutral on the left, connection positions both horizontal and vertical — gives flexibility in busbar routing.