at least two power supply lines;

at least two insulation layers respectively covering corresponding ones of the at least two power supply lines;

a first shield layer and a second shield layer, respectively disposed around corresponding two of the at least two insulating layers, respectively configured to detect leakage currents on the corresponding power supply lines;

at least one shield insulating layer, disposed between the first and second shield layers, configured to electrically insulate the first and second shield layers from each other;

a first signal conductor disposed either between the first shield layer and the corresponding insulation layer or outside the first shield layer, and electrically coupled to the first shield layer; and

a second signal conductor disposed either between the second shield layer and the corresponding insulation layer or outside the second shield layer, and electrically coupled to the second shield layer;

wherein each of the first and second signal conductors is formed of at least one conductor wire and at least one non-conductive filament in a twisted or woven structure.