Arc fault detection device

An AFDD (arc fault detection device) is a circuit protection device, usually fitted in a consumer unit, that monitors the electrical waveform for signatures associated with an arc fault and disconnects the affected final circuit. Arc faults are electrical discharges through damaged insulation, loose connections, crushed cables or similar defects, and they can create high temperatures that may start a fire. IET guidance says AFDDs use microprocessor technology to analyse the waveform and are more sensitive to arcs than conventional circuit protective devices. Manufacturer material describes devices that detect series and parallel arc faults, sometimes combined with MCB (miniature circuit breaker) or RCBO (residual current breaker with overcurrent protection) functions.