Abstract: A testing device for detecting defects in insulation of electrosurgical instruments that includes an implement or wand having a distal end, an electrode for generating a spark adapted to detect a defect in the insulation, and mounting means for removably mounting the electrode to the distal end of the implement. The removable mounting means includes a shank that is received in a socket or bore defined in the distal end of the wand and is engageable with the wand within the socket so the shank can easily be removed from the socket after use. The wand is releasably engageable with the housing by a flexible bracket that extends from the housing. The device may include a pad having a reflective top surface with ridges upon which the surgical instrument to be tested is placed.