The A9D87425 is a 4-pole Acti9 iC60 RCBO (residual-current circuit breaker with overcurrent protection) rated 25 A with a B curve — magnetic tripping between 3 and 5 times In, so it clears short-circuit faults quickly on resistive or general-purpose loads without nuisance trips from inrush. The 30 mA earth-leakage sensitivity provides personnel protection against direct contact, meeting the standard for socket-outlet circuits in residential and commercial distribution boards. Breaking capacity is 6 kA Icu at 380–415 V AC 50 Hz per EN/IEC 60947-2, which means it safely interrupts a fault current up to that level without welding contacts or cascading upstream — sized for most sub-distribution panels where the prospective short-circuit current stays under 6 kA. The thermal-magnetic trip unit combines a bimetal strip for overload protection (time-delayed) and a solenoid for short-circuit protection (instantaneous). The B curve holds the magnetic trip threshold at 3–5× In, so a 25 A unit trips magnetically between 75 A and 125 A — a good match for lighting, socket outlets, and control circuits where the load doesn't draw a heavy starting surge.
Clip-on mounting onto a DIN rail — 8 pitches of 9 mm between poles, so the 4-pole unit occupies 72 mm of rail width. Height is 86 mm, depth 78 mm. Local signalling on the toggle shows ON, OFF, and fault-trip positions — no need to guess whether the device tripped on overcurrent or earth leakage. The fault-trip indication is mechanical, so it works even without auxiliary contacts.