The C125H320FM is a Schneider Electric ComPacT NS new generation 3-pole circuit breaker rated 1250 A at 50 °C, fitted with a MicroLogic 2.0 electronic trip unit. The 2.0 provides L (long-time overload) and I (instantaneous short-circuit) protection — no ground-fault element.
Breaking capacity — what the H code means for your fault level
At 220/240 V AC it delivers 85 kA Icu; at 440 V AC it is 65 kA Icu; at 500/525 V AC it is 50 kA Icu; and at 660/690 V AC it is 42 kA Icu. All figures are per IEC 60947-2. For a 415 V panel with a transformer rating above 2 MVA, 70 kA Icu gives headroom over a typical 50 kA fault-current spec — no need to cascade or current-limit upstream.
Installation and environment constraints
Fixed-mount on a backplate, with front connections both top and bottom. Connection pitch is 70 mm. The breaker is IP40 rated (finger-safe, not washdown) and carries an IK07 impact rating. Operating altitude is 0–2000 m without derating; derate above that. Overvoltage category III suits fixed-installation distribution panels.
Durability and thermal behaviour
Mechanical durability is 10,000 cycles. The MicroLogic 2.0 trip unit includes a 20-minute thermal memory — after a trip, the breaker remembers the thermal state of the conductors for 20 minutes, preventing immediate re-closure onto a still-hot circuit. Power losses at rated current are 44 W.