An instrument designed to manually and/or automatically verify the safety of electrically-powered medical devices. It typically includes an electric current meter that can measure the alternating current (AC) and direct current (DC) in micro- and mili-amperes with a frequency response that complies with appropriate standards. The device can perform AC and DC leakage-current measurements (typically in the range of 1 A to 20 mA) and resistance-to-ground assessments using two- and/or four-terminal techniques in devices up to several ohms; it may also perform patient lead isolation tests in multiple-electrode devices.