T4L 250A 3P LS/I — MCCB for distribution and motor protection
The ABB 1SDA054071R1 is a T4L-series molded case circuit breaker rated 250 A, three-pole, with an LS/I electronic trip unit per IEC standards. The LS/I trip combines long-time (L) and short-time (S) delay for overload and selective coordination, plus instantaneous (I) protection for short-circuit faults — a common setup for main or feeder breakers in low-voltage switchboards and motor control centers.
At 250 A and three poles, this MCCB is sized for main incoming or large feeder circuits in 400 VAC three-phase systems. The LS/I trip unit allows selective coordination downstream — the S delay can be set to ride through temporary overloads while letting branch breakers clear faults, keeping the main breaker closed and the rest of the plant online. It mounts in standard ABB T4L fixed or plug-in bases, common in switchgear lineups and panelboard builds.