The Schneider Electric EZCV250N3125 is a 3-pole moulded-case circuit breaker from the EasyPact EZCV250N range, rated 125 A at 40 °C with a TM-D thermal-magnetic trip unit and integral earth-leakage protection. It's built for distribution duty in fixed-mount backplate panels, with front connections top and bottom and a 35 mm connection pitch. The 20 kA Icu at 440 V AC (50/60 Hz) per IEC 60947-2 tells you it can safely interrupt a fault up to that level without welding or rupturing — that's the short-circuit rating that governs selectivity in a distribution board. The N breaking capacity code places it in the standard-performance tier; for higher fault currents you'd step up to an S or H code in the same frame.
Above 40 °C you derate per the IEC curve; the TM-D unit responds to both overload (thermal bimetal) and short-circuit (magnetic trip). The 20 kA Icu at 440 V AC is the ultimate breaking capacity — the breaker clears that fault once and remains serviceable. At 380–415 V it rises to 25 kA Icu, and at 220–240 V it hits 85 kA Icu. The 440 V rated operational voltage (Ue) matches common 400 V class distribution systems. IK07 impact resistance handles light tool drops during installation.