The C103TM025C is a TM-D thermal-magnetic trip unit for the ComPacT NSX100 molded-case circuit breaker platform, rated 25 A at 50 °C and protecting three poles (3D). It provides LI protection — thermal overload (L) with an adjustable long-time pickup from 0.7 to 1 x In, and fixed magnetic short-circuit protection (I) that trips instantaneously at 300 A. The fixed instantaneous threshold means the magnetic pickup is not field-adjustable; if your coordination study calls for a different Ii, this trip unit locks that value in. The part is an active, current-production item per the manufacturer's lifecycle status.
Storage range of -50 to 85 °C covers warehouse and shipping extremes. No washdown rating; keep it inside the enclosure. The long-time delay (tr) is fixed at 120 to 400 seconds at 1.5 x In, with a 15-second curve at 6 x Ir. This is not adjustable in the field — the curve is set at the factory. For coordination with downstream breakers, verify that the fixed delay band fits your selectivity study.
Traceability and compliance considerations
No earth-leakage protection is integrated — if you need ground-fault detection, pair this with an external earth-leakage relay or choose a different trip unit variant. The manufacturer lists the part as active, meaning it remains in the current catalog and is supported by factory documentation. No PCN or EOL notice is on record.