What is residual current?

Residual current refers to the vector sum of current in each phase, including the neutral line, in a low-voltage distribution line that is not zero. Generally, in the event of an accident on the power supply side, the current flows from the charged body to the ground through the human body, causing the magnitude of the current in phase I and phase II in the incoming and outgoing lines of the main circuit to be unequal. At this time, the instantaneous vector composite effective value of the current is called residual current, commonly known as leakage current.