That figure governs whether this breaker holds coordination with downstream contactors and starters under a bolted fault. The continuous current rating In=630A pairs with an adjustable overload protection Ir spanning 250A to 630A, letting you match the thermal pickup to the actual motor full-load current without swapping the breaker body. Short-circuit protection Isd is adjustable from 3 to 15 times Ir, and the instantaneous pickup Ii is fixed at 15 x In — deterministic, every cycle, no drift. The ETU350M trip unit provides LSI (long-time, short-time, instantaneous) curves, so you can shape the time-current characteristic for selective coordination with upstream feeders. For a 630A motor circuit on a 415V line, that 55kA SCCR headroom keeps the line moving even under worst-case fault conditions.
Spring-cage or box-lug terminals on the line and load sides accept copper conductors sized for 630A — typically multiple cables per phase or busbar stabs. The shunt trip and auxiliary switch terminals are separate, smaller-gauge positions; strip length around 8 mm avoids whiskers under the cage. For a panel builder, the integrated nut keeper kit means the busbar connection studs stay aligned during torque — no dropped hardware, no rework. Fill factor on a 600mm wide enclosure: one frame 1000 breaker plus a feeder section fits comfortably with finger-duct clearance on each side.