The Schneider Electric EZC250N4125 is a 4-pole moulded-case circuit breaker from the EasyPact EZC250N family, rated 125 A at 50 °C and carrying a 20 kA Icu at 440 V AC. The thermal-magnetic trip unit gives you both overload protection (thermal bimetal) and short-circuit protection (magnetic coil) in one package, so no separate relay or CT is needed for basic feeder protection.
Mounting and integration — fixed backplate, front connections
This breaker mounts fixed to a backplate — no DIN-rail clip, so plan for screw-fixing into the enclosure gland plate. Both line and load connections are front-facing, which keeps wiring accessible for panel builders but means the busbar or cable entry needs to come from the front plane. Connection pitch is 35 mm, matching common busbar spacing.
Selectivity and coordination — what the Category A rating tells you
This breaker is Utilisation Category A, meaning it is not specifically designed for cascading selectivity with downstream breakers under short-circuit conditions — it will trip fast on a fault, which is fine for a main or feeder breaker where you want to clear the fault quickly, but if you need full selectivity with downstream MCCBs, you would want a Category B breaker with a short-time delay. The 3t protected poles with neutral unprotected is typical for a 3-phase + N distribution board where the neutral does not need overcurrent protection.