The Schneider Electric A9D52420 is an Acti9 iC60 RCBO — a combined 4-pole residual-current circuit breaker with overcurrent protection, rated 20 A with a C-curve magnetic trip (5 to 10 x In) and integrated 300 mA earth-leakage protection. Breaking capacity is 6 kA Icn at 380–415 V AC 50 Hz per EN/IEC 61009-2-1, and 6 kA Icu per EN/IEC 60947-2. The thermal-magnetic trip unit handles overloads and short-circuits; the integrated residual-current module covers ground faults at 300 mA sensitivity — a single device replacing a separate MCB and RCCB in the panel.
Clip-on mounting to DIN rail, 9 mm pitch per pole — 8 pitches wide for the 4P unit, occupying 72 mm of rail space. Dimensions 86 mm high by 72 mm wide by 78 mm deep; the 78 mm depth is the body behind the panel face, relevant when planning gland-plate clearance or enclosure depth. Tunnel-type terminals accept 1–35 mm² rigid or 1–25 mm² flexible (with or without ferrule); strip length 12 mm, tightening torque 2 N·m. IP40 in a distribution enclosure, IP20 on the device body.
Carries quality labels NF, KEMA-KEUR, VDE, and IMQ. Overvoltage category III per IEC 60364. Limitation class 1 per EN/IEC 61009-2-1. Rated for 50 Hz AC networks only. Tropicalisation class 2. Relative humidity 95% at 55 °C. Electrical durability 10,000 cycles; mechanical durability 20,000 cycles.