A ground check system for checking a ground conductor of a power supply comprising at least one line conductor comprises a pulse generator and a compare circuit. The pulse generator applies a test signal to a test circuit formed at least in part by the ground conductor and the at least one line conductor when an AC voltage on the at least one line conductor is approximately zero volts. The compare circuit compares the test signal passing through the test circuit with at least one test criteria indicative of an unacceptable ground.