400 A Molded Case Breaker with Ekip Dip LS/I Protection
The ABB XT5NU340AEFF000XXX is a 400 A, 3-pole molded case circuit breaker (MCCB) from the XT5N frame, rated for 600 V AC and 600 V DC. It carries the Ekip Dip LS/I electronic trip unit, which gives you adjustable long-time (L) and short-time (S) pickup and delay, plus fixed instantaneous (I) protection. The 400 A frame is sized for main feeder or large motor branch protection where you need selectivity downstream. For a commissioning engineer verifying the protection scheme: the LS/I curve means you can coordinate the breaker with downstream devices by setting the S delay — a common requirement on a panel fed by a transformer or generator. The 600 V DC rating covers battery banks or UPS outputs, though verify the DC polarity marking on the terminals before energizing.
Duty and Deployment Context
The XT5N frame mounts in a standard switchboard or panel enclosure on a bolted bus connection — no DIN-rail adapter for this frame class. The 400 A continuous rating and 600 V AC/DC withstand let it serve as a main disconnect on a 600 V distribution panel. For a field-service tech isolating a fault: the breaker's rotary handle mechanism provides visible indication of the contact position. The Ekip Dip unit stores the last-trip cause (L, S, or I) on the LCD, which cuts down troubleshooting time on a downstream short or overload event.