The C25B42D160 is a Schneider Electric ComPacT NSX circuit breaker in the NSX250B frame, fitted with a MicroLogic 2.2 electronic trip unit rated 160 A at 40 °C. It is a 4-pole (4P) device with a breaking capacity of 25 kA Icu at 380/415 V AC per IEC 60947-2, and 40 kA Icu at 220/240 V AC. The electronic trip unit provides L (long-time overload), So (short-time short-circuit with fixed delay), and I (instantaneous short-circuit) protection — all adjustable via the front dials. This is a distribution-grade breaker (Category A) suited for panelboard or switchboard mounting on a backplate.
If your panel ambient runs higher, derate per the manufacturer's curve — the electronic trip unit's thermal memory stores 20 minutes of heating history before and after tripping, so nuisance trips on re-close are unlikely. The 4-pole configuration with neutral on the left means all four poles are protected; the breaker ships without earth-leakage protection (Vigi module sold separately, slots available).
Dimensions: 161 mm height, 140 mm width, 86 mm depth. Front connections on both line and load sides. The 35 mm connection pitch matches standard busbar systems. IP40 enclosure protection keeps out tools and fingers — suitable for indoor panel installation.