The C40F4TM250D is a 4-pole ComPacT NSX DC circuit breaker with a TM-DC thermal-magnetic trip unit rated 250 A at 40 °C. The breaking capacity is 36 kA Icu at 750 V DC with three poles in series, and the same 36 kA at 250 V DC with one pole. The rated insulation voltage is 750 V DC, so the breaker is built for 750 V DC systems, not just 500 V. It mounts fixed to a backplate, not on DIN rail. The 185 mm width and 255 mm height mean it takes a standard ComPacT NSX cutout in a panel. Toggle control gives manual on/off and trip indication. IP40 front-of-panel protection keeps tools and fingers out; IK07 impact rating handles incidental knocks during commissioning.
Deployment context
This breaker goes into a DC distribution panel — think battery banks, DC bus systems in data centers, solar combiner boxes, or traction power supplies. The 4-pole configuration with four protected poles (4D) lets you break both positive and negative conductors in a two-wire DC system, or use series poles for higher voltage (750 V with three poles in series). Front connections on both line and load sides simplify busbar or cable routing in a panel.