The Schneider Electric A9KR16263 is an Acti9 ID K residual current circuit breaker (RCCB) — a 2-pole, 63 A, 300 mA Type AC device for 220...240 V AC 50 Hz networks. Rated breaking and making capacity is 630 A (Idm / Im), and the unit is voltage-independent in its residual current tripping — it operates regardless of whether the line voltage is present, which matters for safety when the supply is lost but a fault path still exists. The 300 mA sensitivity (Type AC, instantaneous) is sized for general-purpose protection against sinusoidal AC earth faults. It covers the wiring and connected equipment in a group submain, not personnel shock protection (30 mA or lower would be required for that). Standards compliance is EN/IEC 61008-1, which covers RCCBs for household and similar uses.
Mounts via clip-on to a 36 mm wide DIN rail — occupies 4 modules of 9 mm pitch. Neutral is on the left. Rated for ambient operation from -5 to 55 °C, storage from -25 to 85 °C, with 95 % relative humidity at 55 °C (tropicalisation class 2 per IEC 60068-1). Pollution degree 2 — suitable for normal industrial or commercial indoor environments where only non-conductive contamination occurs.