The A9F88420 is a Schneider Electric Acti9 iC60H miniature circuit breaker rated 20 A with a B-curve (magnetic tripping at 4 x In ±20 %, so 80 A instantaneous), 4 poles, and thermal-magnetic trip. It carries a breaking capacity of 42 kA Icu at 12–133 V AC 50/60 Hz per EN/IEC 60947-2, stepping down to 30 kA at 220–240 V AC, 15 kA at 380–415 V AC, and 10 kA at 440 V AC. For the EN/IEC 60898-1 rating, it delivers 15 kA Icn at 400 V AC. The 4 protected poles mean it switches and protects all four conductors in a three-phase-plus-neutral distribution circuit — typical for a sub-distribution board or a machine infeed where you need full isolation on all poles. The B-curve is the key selection parameter here: it trips magnetically between 3 and 5 times rated current, so the 20 A unit clears short-circuits at roughly 60–100 A. The thermal-magnetic trip unit covers overloads (thermal bimetal) and short-circuits (magnetic solenoid) in one package, with a separate earth-leakage block available if needed. Electrical durability is 10,000 cycles, mechanical 20,000 — figures that match the expected service life in a distribution board that sees occasional switching.
Dual-certified to EN/IEC 60947-2 (industrial) and EN/IEC 60898-1 (household / similar), so it qualifies for both industrial panel builds and commercial distribution boards.