Panel fit and protection profile
The Schneider Electric A9N3P03DIN is a 3-pole Acti9 xC60 miniature circuit breaker rated at 3 A with a D tripping curve. The D curve means magnetic tripping occurs at 12 x In ±20 % — so it holds through the high inrush of motor or transformer loads without nuisance trips, then clears fast on a hard fault. Breaking capacity is 10 kA Icn at 380–415 V AC 50/60 Hz per IS/IEC 60947-2, and 15 kA Icu at 100–125 V DC. The thermal-magnetic trip unit protects the downstream cable and load. The suitability-for-isolation marking (yes, per IS/IEC 60947-2) means you can use it as a local disconnecting means for the downstream equipment.
Integration notes
IP20 finger-safe protection means it is intended for enclosure use, not open-panel washdown areas. Tropicalisation level 2 per IEC 60068-1 means the part is treated for storage and operation in warm, humid climates — relevant if the panel ships to Southeast Asia or coastal regions.