The C163MG125D is a TM-G thermal-magnetic trip unit for the ComPacT NSX160 DC range, rated 125 A at 40 °C and built for 750 V DC networks. It's the LI (overload + short-circuit) version, with a fixed instantaneous pick-up of 530 A. It's listed under EN/IEC 60947-2, so it carries the same short-circuit coordination pedigree as the AC ComPacT line but tuned for DC. The 3D protected-pole configuration covers all three poles for DC interruption, and the fixed mounting keeps it locked into the NSX160 DC cradle — no field swap to a different frame size.
Lifecycle status is current/active per the manufacturer — no EOL notice on this order code. That means it's still a valid BOM line for new generator panels and DC switchgear. Pollution degree 3 per IEC 60947-1 and IP40 front face mean it's fine inside a standard IP54 enclosure but not for direct washdown. The storage range of -50 to 85 °C and operating range of -25 to 70 °C cover most industrial environments short of a freezer tunnel or a furnace wall.
The long-time pickup (Ir) is adjustable from 0.7 to 1 x In, so you can dial the 125 A trip unit down to 87.5 A if the generator's continuous rating is lower. That's a real advantage when the same frame size covers multiple genset outputs — one spare trip unit can serve several machines with a screwdriver adjustment. Class II electrical shock protection means no earth connection needed on the trip unit itself — it's double-insulated. That simplifies wiring in a DC panel where you already have a floating or IT system.