AFDD stands for Arc Fault Detection Devices. An arc is a visible plasma discharge produced by electrical currents passing through a nonconductive medium like air. Arc fault detection devices are protected devices installed in the consumer units. These devices protect against arc faults. These devices can easily detect any unusual event with the use of micro processing technology and analyze the waveform of the electricity. It protects the affected circuits and prevents fire damage. These devices have a test button that an end-user may operate to prove the mechanical operation of the device.