The Schneider Electric A9N19644 is an Acti9 DPN Vigi RCBO — a combined overcurrent and earth-leakage protection device in a single 1P+N module. Its Type A-SI (Super Immunised) designation means the residual current detection is filtered against nuisance tripping from high-frequency leakage typical of modern switched-mode power supplies, variable-speed drives, and LED drivers.
Rated at 16 A (In) with a C-curve magnetic trip (5–10 × In), so it handles moderate inrush from small motors, transformers, or capacitor banks without nuisance opening. The 300 mA earth-leakage sensitivity is a fixed, instantaneous trip — no time delay — so it's suited for outgoing circuits where a fast disconnect from ground faults is required and where coordination with upstream 30 mA or 100 mA RCDs is not needed. Breaking capacity is 6 kA Icn at 230 V AC, per EN 61009, which covers most residential and light commercial distribution panels where the prospective fault current stays under that threshold. Rated insulation voltage is 400 V AC, operational voltage 230 V AC, and the device is rated for pollution degree 3 and overvoltage category III — standard for fixed-installation distribution boards.
Snaps onto a DIN rail (mounting support: DIN rail) and occupies 4 modules of 9 mm pitch — 36 mm total width. Neutral is on the left, phase on the right. The toggle provides local ON/OFF indication. Rated for 20,000 electrical and 20,000 mechanical cycles, which is typical for a distribution-grade RCBO.