A system and method is disclosed for detecting a specific voltage phase, from a multiphase voltage source, and a specific outlet of an intelligent power strip, that is associated with a residual current flow. The method accomplishes this by using a system that employs a statistical time series analysis using a Pearson's correlation coefficient calculation to measure the linear dependence between the discretely sampled residual current waveform and each phase and outlet's discretely sampled current waveforms, in turn. A residual current as low as 1 mA can be accurately measured and its associated voltage phase source, as well as which outlet of an intelligent power strip it flows out of, can be reliably determined.