Schneider Electric C25H4TM125 ComPacT NSX Circuit Breaker, 1

The C25H4TM125 is a Schneider Electric ComPacT NSX circuit breaker on the NSX250H frame, 4-pole, with a TM-D thermal-magnetic trip unit rated 125 A at 40 °C. The TM-D provides L (thermal overload) and I (magnetic short-circuit) protection — no earth-leakage module built in, so if you need ground-fault protection you add a Vigi add-on block separately. The 125 A rating sets the continuous current limit for a distribution feeder or large motor branch; at 40 °C ambient it carries full load without derating, but above that you follow the manufacturer's temperature correction curve. Breaking capacity is the headline: 70 kA Icu at 380/415 V AC, 65 kA at 440 V, 50 kA at 500 V, and 35 kA at 525 V. At 240 V it hits 100 kA Icu. Mounts on a backplate, not a DIN rail — the 140 mm width and 161 mm height fit the ComPacT NSX cutout pattern. IP40 enclosure protection means it's fine in a clean panel but not washdown or outdoor without a cover.