The C254MG200 is a TM-G thermal-magnetic trip unit for the ComPacT NSX250 molded-case circuit breaker frame. It is rated 200 A at 40 °C, carries 4 protected poles (4D), and is built for generator protection applications per EN/IEC 60947-2. The LI protection profile gives you fixed long-time delay (120 to 400 s at 1.5 x In) and a fixed instantaneous pick-up at 440 A, with the Ir long-time pick-up adjustable from 0.7 to 1 x In.
If your panel runs hotter — say 50 °C or 60 °C — you need to apply the manufacturer's thermal derating curve (not shown here, but standard for TM-G units). The 440 A instantaneous pick-up means magnetic trips start at roughly 2.2 x In, which is typical for generator protection: it rides through the inrush of a large alternator without nuisance tripping, but clears a hard fault fast.