A method, system and computer readable medium for determination of distance to an electrical fault within a device. A signal generator excites the device with an electrical input signal. The device comprises an open circuited electrical transmission line. A frequency domain analyzer analyzes part of the signal reflected from the device for determination of the locations of resonant frequency of the signal within the device. A computer calculates the distance to the fault within the device, based on the resonant frequency. The distance to the fault is one quarter wavelength distance into the device at the resonant frequency. A frequency sweeper sweeps the frequency of the input signal and repeated calculation of the distance to the fault made at a plurality of resonant frequencies during the frequency sweep confirms the distance to the fault by convergence of the result of the repeated calculations to substantially the same location.