The testing methods and techniques that are used for measuring electrical characteristics and parameters of dc transmission lines and earth electrode lines include the following topics: a) Test safety precautions b) Measuring instrument requirements c) Induced-voltage and induced-current testing d) Polarity verification and insulation resistance testing e) Measurement of dc resistance f) Measurement of impedance frequency characteristics Purpose The purpose of this guide is to present practical testing methods that may be used for measuring induced voltage and current@ polarity@ insulation resistance@ dc resistance@ and impedance frequency characteristics of dc transmission lines and earth electrode lines.