Abstract: A method of detecting a series arc fault in an alternating current electrical signal is provided. A method for detecting a series arc fault in an alternating current electrical signal, comprising: a) calculating discrete wavelet coefficients using a current signal as an input for the discrete wavelet coefficient calculations, and outputting discrete wavelet coefficient filtered output; b) subsampling the discrete wavelet coefficient filtered output and outputting a subsampled output; c) calculating critical variables from the subsampled output; d) determining from the critical variables whether a series arc fault is present in the current signal; and e) outputting an signal indicating that a series arc fault is present in the current signal, if substantially all of the critical variables meet a predetermined criteria.