The ETU350M trip unit provides LSI protection — long-time (Ir adjustable 250 A to 630 A), short-time (Isd adjustable 3 to 15 × Ir), and instantaneous (Ii fixed at 15 × In).
Deployment context
Mounts in a standard IEC switchboard or motor control center. The nut keeper kit secures the breaker to the mounting plate — a detail that matters when you're torquing down bus connections and don't want the hardware to shift.
The 630 A frame with Ir adjustable down to 250 A covers a wide motor range — roughly 130 kW to 315 kW on a 400 V supply, depending on the motor's full-load current. The LSI curve lets you coordinate with downstream contactors and overload relays: set Isd to ride through motor starting inrush (typically 6 to 8 × FLA) and set the instantaneous pickup at 15 × In for bolted-fault protection.