The ABB XT5SU340AEFF000XXX is a 400 A, 3-pole molded case circuit breaker (MCCB) from the XT5S series, fitted with an EKIP DIP LS/I 400 trip unit. The LS/I designation means it provides long-time and short-time protection plus instantaneous fault clearing — a standard fit for feeder and distribution duties in commercial and industrial switchboards. UL and CSA markings confirm acceptance for North American panel builds.
Rated 400 A continuous at 40 °C, this MCCB handles the full load of a large feeder or a high-current downstream distribution panel. The EKIP DIP LS/I electronic trip unit allows field-adjustable long-time pickup and delay, short-time pickup and delay, and instantaneous pickup — so the same breaker can be tuned for cable protection, busway protection, or as a main for a motor control center without swapping the trip unit. The 3-pole FF (fixed front terminals) pattern accepts standard bus bar or cable connections and keeps the panel layout predictable.