The Schneider Electric C125N35EFM is a ComPacT NS new generation molded case circuit breaker (MCCB) from the NS630b...1600 range, rated 1250 A at 50 °C with a MicroLogic 5.0 E electronic trip unit. It is a manually operated, 3-pole device built for distribution applications on AC networks at 50/60 Hz. The 5.0 E trip unit provides LSI protection — long-time overload, short-time short-circuit, and instantaneous short-circuit — plus integrated energy metering via the LCD display.
The 1250 A frame and trip rating at 50 °C sets the continuous current capacity; above 50 °C the breaker must be derated per IEC 60947-2. For selectivity with downstream breakers, the short-time delay (S protection) on the MicroLogic 5.0 E allows coordination up to the Icw rating. The electronic trip unit includes a 20-minute thermal memory, which prevents immediate reclose after a trip on overload by simulating the cooling curve of the protected conductor. Power losses are 44 W at rated current — relevant for enclosure thermal management.
Fixed mounting on a backplate, with front connections on both line and load sides. Connection pitch is 70 mm. The breaker measures 327 mm high, 210 mm wide, and 147 mm deep. IP40 enclosure protection (finger-safe) and IK07 impact resistance.