What this 40 A C-curve MCB does on the panel
The Schneider Electric A9N3P40CGN is a 3-pole miniature circuit breaker from the Acti9 xC60 range, rated 40 A with a C tripping curve (magnetic trip between 5 and 10 times In). It clips onto a 35 mm DIN rail and protects distribution circuits in commercial and industrial panels against overloads and short circuits, with a breaking capacity of 10 kA at both 240 V and 415 V AC per IS/IEC 60898-1. The C curve means it tolerates moderate inrush — suitable for mixed loads like lighting banks, small motor starters, and control transformers where the starting surge stays under 10× the 40 A rating. The thermal-magnetic trip unit handles sustained overloads via the bimetal strip and instantaneous shorts via the solenoid.
Occupies 9 mm pitches × 6 = 54 mm width. The tunnel terminals accept up to 35 mm² rigid or 25 mm² flexible conductors; strip 13 mm and torque to 3.5 N·m. The bottom terminals use the Biconnect system for dual-conductor termination — useful for looping through to downstream loads without a separate terminal block. IP20 finger protection on the front; install inside a panel or enclosure that provides the environmental seal.