The C25B4TM160 is a 4-pole ComPacT NSX250B circuit breaker from Schneider Electric, fitted with a TM-D thermal-magnetic trip unit rated 160 A at 40 °C. It's built for distribution applications — think main or feeder breakers in commercial and industrial panelboards where you need a compact, high-breaking-capacity device that meets EN/IEC 60947-2. The 40 kA Icu at 220/240 V AC and 25 kA at 380/415 V AC give it solid fault-clearing headroom for most low-voltage distribution networks.
The TM-D trip unit provides L (overload) protection via a thermal bimetal element and I (short-circuit) protection via a magnetic coil. The thermal curve is fixed, not adjustable — the Ir setting is at the factory 160 A. The magnetic pickup is fixed as well, typically around 10× In for the TM-D, so it's a straightforward, no-dial breaker: set it and forget it. Neutral protection is set at 1 × Ir (full rated current), and the neutral pole is on the left side of the 4-pole frame.
Connection pitch is 35 mm, and both line and load connections are front-accessed, which simplifies busbar and cable routing in a panel. It's IP40 rated (finger-safe) and carries IK07 impact resistance, so it's fine for enclosed distribution boards but not for washdown environments. Mount it horizontally or vertically flat on the backplate — no derating needed for orientation. The toggle control is manual, no motor operator included. Five accessory slots are available on the NSX250B frame for adding shunt trips, auxiliary contacts, or undervoltage releases later.