The Schneider Electric C25B6TM125C is a ComPacT NSX250B moulded-case circuit breaker with a 125 A thermal-magnetic TM-D trip unit, 4 poles, and a B breaking capacity code — 25 kA Icu at 415 V AC. That B rating means it's sized for distribution boards where the available fault current stays under 25 kA at 415 V; the same breaker delivers 40 kA Icu at 240 V and 20 kA at 440 V, so it covers a range of service-entrance and sub-feed applications without swapping frames. The thermal-magnetic TM-D trip handles overloads (L protection) via a bimetal element and short-circuits (I protection) via a solenoid — fixed, non-interchangeable, and factory-calibrated. For a 125 A distribution breaker that's the standard choice: no electronic adjustment, no ground-fault module, just a reliable trip curve that coordinates with downstream MCBs in a typical panel.
IP40 front face, IK07 impact resistance.
The 161 x 140 x 86 mm envelope (H x W x D) fits standard MCC bucket cutouts and panel-mounting footprints for 250 A frame breakers. Front connections top and bottom, neutral on the left, toggle actuator.
Electrical endurance: 20,000 cycles at 440 V at half-rated current, 10,000 at full rated current. That's typical for a moulded-case breaker in distribution duty — not a switching device for frequent motor starts, but fine for infrequent manual isolation and automatic fault clearing.