The C256TM200C is a thermal-magnetic trip unit for the ComPacT NSX250 molded-case circuit breaker frame, rated 200 A at 50 °C. It provides LI protection — thermal overload (L) via a bimetallic element and magnetic short-circuit (I) with an adjustable instantaneous pickup from 5 to 10 x In. The 4-pole 3D configuration protects three poles and leaves the neutral unprotected (neutral position left, no protection). This trip unit is designed for distribution applications in fixed-mount MCCBs, meeting EN/IEC 60947-2 for low-voltage switchgear. IP40 front face keeps tools and fingers out. The TM-D trip unit is the standard thermal-magnetic offering for the NSX100…250 frame — no electronic adjustability on the long-time delay (fixed at 120…400 s at 1.5 x Ir, or 15 s at 6 x Ir), but the Ir pickup is adjustable 0.7…1 x In. That fixed tr suits simple overload curves where coordination studies are minimal. For a 200 A feeder on a 400 V distribution panel, this covers motor control center incomers or subfeeders with moderate cable protection needs.
The 200 A rating is at 50 °C ambient — the standard thermal benchmark for MCCB trip units. If your panel operates at 40 °C, the unit carries the full 200 A without derating; above 50 °C, thermal performance degrades per the manufacturer's curve (not provided here, but typical for TM-D units). The 690 V AC / 750 V DC rated operational voltage covers most 400 VAC distribution and some 500 VDC solar or battery strings, but the 4-pole 3D neutral configuration means the neutral pole is unmonitored — verify that your system's neutral protection requirements are met (if full 4-pole protection is needed, look for a 4D variant). The adjustable instantaneous pickup (Ii) from 5 to 10 x In (1000 to 2000 A at the 200 A rating) lets you set short-circuit protection coordination with downstream breakers. A setting of 10 x In provides better selectivity with smaller branch breakers; 5 x In gives faster clearing for high-fault conditions. The fixed long-time delay (tr) at 120…400 s at 1.5 x Ir means the overload curve is not field-adjustable — coordination studies must accept the factory curve shape.