A system and method for detecting faults within an electrosurgical instrument having a shield and an active electrode uses multiple possible fault conditions. In one embodiment the monitoring system comprises an electrosurgical generator coupled to the electrosurgical instrument and adapted to deliver power to the active electrode of the electrosurgical instrument, monitoring circuitry coupled to the electrosurgical generator and the electrosurgical instrument, wherein the monitoring circuitry comprises an active electrode voltage sensor an active electrode current sensor and a shield current sensor. The monitoring circuitry measures at least two of the active voltage, the active or return electrode current, and the shield current.
