What this breaker is and what it carries
The ABB 1SDA068083R1 is an XT4N 160 TMA distribution circuit breaker in the fixed-front, fixed-connection version. Its continuous rated current (In) is 40 A, mounted on a 160 A frame (Iu). The breaker handles 690 V at 50/60 Hz and uses a thermal-magnetic (TMA) trip unit, adjustable across the 40–400 A range per the type designation.
Trip unit and adjustment
TMA stands for thermal-magnetic adjustable. The In setting is fixed at 40 A from the factory, but the trip unit accepts adjustment of the thermal overload and magnetic short-circuit thresholds across the 40–400 A range. That makes it field-flexible for circuit re-rating without swapping the breaker.