The Schneider Electric A9D71816 is an iC60N RCBO — a combined residual current breaker with overcurrent protection from the Acti9 range. It packs a 1P+N thermal-magnetic MCB and a 30 mA earth-leakage module into a single 2-module-wide (18 mm per pitch) clip-on DIN-rail unit, saving a slot over separate devices. The D curve (250 A surge current withstand) and 6 kA breaking capacity at 230/240 V AC mean it handles motor-starting inrush or transformer loads without nuisance trips, while the 30 mA sensitivity catches ground faults on the outgoing circuit.
At 77.5 mm deep and 2 x 9 mm pitches wide (18 mm total), it clips onto standard DIN rail and leaves room in the enclosure for adjacent breakers or contactors. IP20 means it's for enclosed use only, not washdown. The toggle gives local ON/OFF indication, and the padlock provision (Ø 4 mm) lets you lock it out for maintenance.
The A9D71816 carries approvals to BS EN 61009-1, IEC 61009-1, IEC 61009-2-2, and AS/NZS 61009.1 — the core RCBO standards for overcurrent and residual current protection. That covers UK, European, and Australian/New Zealand installations. It's rated for TN earthing systems and tropicalised (class 2) for humid environments (95% RH at 55 °C).