The C254TM250C is a TM-D thermal-magnetic trip unit from the Schneider Electric ComPacT NSX100...250 range, rated 250 A at 50 °C for 4-pole 4D distribution applications. It provides LI protection — thermal overload (L) with an adjustable long-time pickup from 0.7 to 1 x In and a fixed delay, plus magnetic short-circuit (I) adjustable from 5 to 10 x In. Rated operational voltage is 690 V AC 50/60 Hz or 750 V DC, certified to EN/IEC 60947-2.
The adjustable long-time pickup (0.7–1 x In) lets you set the overload threshold to match the protected cable or load, while the fixed delay (120–400 s at 1.5 x In, 15 s at 6 x Ir) coordinates with downstream breakers. The magnetic instantaneous trip adjustable from 5 to 10 x In gives selectivity headroom for motor starts or transformer inrush without sacrificing short-circuit protection.
This is a fixed-mount trip unit for the ComPacT NSX250 molded-case circuit breaker frame — it snaps into the breaker body, not onto a DIN rail directly. The 4-pole 4D configuration protects all four poles, with the neutral on the left and a 1 x Ir neutral protection setting. IP40 front face protection handles typical panel dust, but keep it inside an enclosure for washdown areas.