Abstract: An apparatus and method for locating an obstruction, leak or fault in an electrical cable segment, and determining the extent thereof, comprising a method and apparatus for supplying an interruptible pressurized gas to the cable's interstitial void space, first and second valves for directing the flow of the gas, a first device for acquiring data on the flow rate of gas to or from the interstitial void space and generating a first electronic signal proportional thereto, the first flow data acquisition device being in gaseous communication with the first valve, a second device for acquiring data on the flow rate of gas to or from the interstitial void space and generating a second electronic signal proportional thereto, the second flow data acquisition device also in gaseous communication with the second valve, and a method and apparatus for numerically relating the first and second electronic signals generated by the first and second data acquisition devices to determine the location and extent of the leak or