Earth fault detector

A earth fault detector connected to a non-ground high voltage battery and detecting an earth fault of a system in which the high voltage battery is provided, the earth fault detector comprising:

• a controller;
• a detection capacitor operating as a flying capacitor;
• a positive side first resistance connected to a positive side of the high voltage battery;
• a negative side first resistance connected to a negative side of the high voltage battery;
• a positive side second resistance of which one end is grounded and a voltage of another end is measured by the controller;
• a negative side second resistance of which one end is grounded;
• a positive side C contact switch alternatively switching a connection destination of a first end of the detection capacitor to either a path including the positive side first resistance or a path including the positive side second resistance based on an instruction of the controller;
• and
• a negative side C contact switch alternatively switching a connection destination of a second end of the detection capacitor to either a path including the negative side first resistance or a path including the negative side second resistance based on the instruction of the controller.