The Schneider Electric C25B44B240 is a ComPacT NSX 250B moulded-case circuit breaker rated 240 A, 4-pole, with a MicroLogic 4.2 AB electronic trip unit. It is designed for special applications requiring integrated earth-leakage protection (R) alongside overload (L), short-time short-circuit (So), and instantaneous short-circuit (I) protection — all in one device. The B breaking capacity code means 25 kA Icu at 415 V AC, 50/60 Hz per IEC 60947-2. At 240 V AC it delivers 40 kA Icu; at 440 V AC it holds 20 kA Icu.
The 4-pole unit occupies a 140 mm width, 161 mm height, 86 mm depth footprint. IP40 enclosure protection, IK07 impact resistance. Pollution degree 3, overvoltage category IV — suited for industrial panels where conductive dust and transient overvoltages are present. Ambient humidity range 0–95 %.
Durability and signalling
Rated for 20,000 mechanical cycles and 20,000 electrical cycles at 440 V In/2, 10,000 cycles at 440 V In, 10,000 cycles at 690 V In/2, and 5,000 cycles at 690 V In. The electrical durability figures are per IEC 60947-2 utilisation category A. Local signalling includes a flashing green LED for ready-to-operate, a red LED at 105 % Ir for overload, and an orange LED at 90 % Ir for pre-alarm. The OFF operating mode uses the IΔn rotary switch for earth-leakage reset and test.