What it is and what it does
The ABB 1SDA062867R1 is a T7S-series molded-case circuit breaker rated 1250 A, three-pole, with LSI (long-time, short-time, instantaneous) electronic trip unit, built to IEC standards. It sits in a switchboard or panel as the main feeder or large-load protection point — think a 1250 A bus riser, a big transformer secondary, or a bank of drives. The LSI trip gives you adjustable pickup and delay on both the long-time and short-time bands, plus a fixed instantaneous threshold, so you can coordinate selectively downstream without nuisance tripping on motor inrush.
What the ratings mean for fit
1250 A continuous at 40 °C is the frame rating — that is the current the breaker can carry without derating in a typical enclosed panel. The three-pole LSI trip covers three-phase circuits. The IEC rating tells you it is built to IEC 60947-2, which governs air-break molded-case breakers for industrial use; that standard defines the breaking capacity, the coordination categories, and the test sequences. If your panel was designed to a UL 489 standard, check the interrupting ratings against your available fault current — the T7S has different SCCR tables for IEC vs UL installations, and the trip unit itself may need a different firmware variant for UL-listed coordination.