An apparatus and method for evaluating power transmission conductors is disclosed. The apparatus is configured to evaluate a charged power transmission conductor at a distance and includes a telescope assembly configured to transmit light to the conductor and receive a reflected light, in response to the transmitted light, from the conductor. The apparatus further includes control electronics configured to analyze the reflected light and determine a ratio based on two pre-determined frequencies, wherein the ratio is correlated with levels of iron oxide corrosion to confirm the presence of oxides that have leached through strands of the conductor.