Safety criteria for testing ground systems within their influence zone

The aim of the present paper is to investigate the appropriateness of a new testing way consisting in the use of one or more auxiliary electrodes at short distances. If correctly applied, the method gives always conservative results. In the measurement the leakage current distribution around the ground electrode introduces a systematic error that increase the gradients in the area influenced by the current electrodes at short distance. The authors demonstrate that the error is precautionary and so the values of surface potentials measured with the auxiliary electrode at reduced distance are conservative. Simulations done by a program based on the Method of Moments confirm these effects.