OPAC (optical power attached cable) is a type of fiber optic cable that is installed by attaching to a host conductor along overhead power lines. One way round this is to install aerial fiber cables close to power lines, such as on mixed use poles which also carry electricity. Obviously, these fiber cables need to be resistant to electricity, which can be difficult as many aerial cables contain high tensile steel (HTS) for tensile strength. bles in a high voltage environment, with typical line voltages of 115 kV or more, requires the evaluation of certain critical parameters.