A fault detection system for a machine having a plurality of electrical conducting elements insulated from a frame ground of the machine is disclosed. The fault detection system may include a high voltage DC power source, a positive high voltage bus connected to a positive terminal of the high voltage DC power source and providing high voltage electrical power to the plurality of electrical conducting elements, and a negative high voltage bus connected to a negative terminal of the high voltage DC power source and returning high voltage electrical power from the plurality of electrical conducting elements. At least one of the positive and negative high voltage buses may be selectively connected through a plurality of switches to plural zones of the electrical conducting elements, with each of the plural zones being electrically connected in parallel, and selectively connected to the high voltage DC power source by one of the plurality of switches. A low voltage DC power source may be configured to form part of a leakage current detector selectively connected through each of the plurality of switches to each of the plural zones for detecting leakage current between an electrical conducting element and the frame ground.