The C10B4 is a ComPacT NSX100B basic frame — a 4-pole, 100 A molded-case circuit breaker frame without a trip unit, intended for distribution applications. The Ics (service breaking capacity) at the same voltage is also 25 kA, meaning it can reclose after a fault at full rated current without derating — a practical advantage for selectivity studies. The 8 kV impulse withstand (Uimp) means it survives surge events typical of overvoltage category III environments — think main distribution boards. Once you add a thermal-magnetic or electronic trip unit (sold separately), the actual protection curve is set by that module.
Deployment and integration
Mounts fixed to a backplate (not DIN rail) — the 140 mm width, 161 mm height, and 86 mm depth fit standard ComPacT NSX cutouts. Front connections top and bottom, neutral on the left, 35 mm connection pitch. Toggle control for manual operation. Electrical durability is 30,000 cycles at 440 V AC at In, and 50,000 cycles at In/2. Mechanical durability is 50,000 cycles. That's typical for a distribution-grade MCCB — expect decades of service in a fixed installation with infrequent switching.