A system and method for detecting faults within a shielded electrosurgical instrument are disclosed. The method includes sensing at least two of: an active voltage in the active electrode； a current in the active or return electrodes； or power in the electrosurgical instrument shield. The method also includes determining whether a power fault exists, wherein determining whether a power fault exists includes multiplying the sensed current and the sensed active voltage. The method also includes determining at least one of: whether one or more current faults exists； or whether a capacitance fault exists. The method also includes altering power delivery to the active electrode if any of the power fault, current faults, or capacitance faults exist.
