Study on Improvement of Earth Resistance Measurement Method without Auxiliary Electrodes

This paper describes an earth resistance measurement method that does not require auxiliary electrodes. Conventional methods, such as the fall of potential method, are not effective for measuring the earth resistance of ground covered with asphalt because auxiliary electrodes cannot be set in the ground. A method that does not need auxiliary electrodes has been developed to solve this problem [1]-[7]. This method uses a return wire instead of the auxiliary electrodes and is able to measure earth resistance greater than 100 . However, it cannot be applied to low earth resistance measurement, especially that less than 50 . Thus, to measure low earth resistance, in this study, we propose an improved method that uses two return wires. We evaluated the new method compared with measured data obtained by the conventional method. The results showed that an earth resistance less than 100 can be measured within an error of 15 %.