What this RCBO does on the board
The A9TDND620 is a 1P+N residual current circuit breaker with integrated arc-fault detection (RCBO) from the Acti9 Active iCV40H ARC series. It clips onto a DIN rail and protects a single-phase final subcircuit at 20 A rated current, C curve, with a 10 kA breaking capacity at 230 V AC 50 Hz per EN/IEC 61009-2-1. The thermal-magnetic trip unit handles overload and short-circuit; the electronic module also detects series and parallel arcing faults per EN/IEC 62606, making it suitable for circuits where arc-fault protection is specified (e.g., sleeping accommodation, high-risk occupancies). The white (RAL 9003) toggle gives local ON/OFF and fault-trip indication plus a dedicated arc-fault diagnostic LED.
Rated at 20 A, C curve — the magnetic trip threshold is 5 to 10 times In (100–200 A), so it will hold motor inrush and capacitive loads that a B curve would nuisance-trip on. Limitation class 3 means it lets through less energy than a class 1 device, reducing downstream stress. The voltage measurement accuracy of ±2 % and power measurement accuracy of ±5 % come from the integrated metering function, not from a separate meter — useful for load monitoring on a single circuit.
Cables enter from top or bottom; strip 14 mm and torque to 2 N·m. The device occupies 4 modules of 9 mm pitch (36 mm total width). Pollution degree 2 (normal factory/office environment) and overvoltage category III (distribution board downstream of the main panel). Tropicalisation severity B per IEC 60068-2-30 for 28 days means it handles high humidity (95 % at 55 °C) without corrosion — relevant for coastal or unconditioned plant rooms.