The Schneider Electric A9F03725 is an Acti9 iC60N miniature circuit breaker rated 25 A, 3P+N, curve B, designed for distribution boards on DIN rail. It's the part you reach for when you need a thermal-magnetic MCB that isolates the circuit (suitability for isolation confirmed per EN/IEC 60898-1 and 60947-2) and handles both AC and DC networks.
At 12–133 V AC it's rated 36 kA Icu per EN/IEC 60947-2 — that's the ultimate short-circuit capacity, one-shot. At 220–240 V it drops to 20 kA Icu; at 380–415 V it's 10 kA Icu; at 440 V it's 6 kA Icu.
Trip curve and selectivity
Curve B means the magnetic trip operates at 4 x In ±20 %, so for a 25 A breaker the instantaneous trip sits between 80 A and 120 A. That's the standard choice for resistive loads and long cable runs where you want to avoid nuisance tripping from inrush. The thermal-magnetic trip unit handles overloads on the thermal side; the magnetic side clears short-circuits. Overvoltage category IV means it's rated for the main distribution panel — not just sub-panels.
IP20 rated — finger-safe terminals, but not for wet locations. Earth-leakage protection requires a separate Vigi block, not integrated. The trip indicator gives local visual confirmation of the tripped state, which speeds fault isolation on a crowded panel.