This work is devoted to a comparative study of the Safe Approach distances calculations when live works on high voltage structures are to be performed. These distances must be determined by the most rigorous way in order to ensure a total security of the operators in charge of these works. Several authors propose different empirical formulas of the statistical breakdown voltage U 50 as a function of the gap Du in rod plane electrode configuration under normalized surge overvoltage. Safe

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... s to be respected in high voltage line works are determined on the basis of these statistical breakdown voltages. A comparative survey will be achieved between the proposed approaches, and their use in the minimal distance approach assessment techniques recommended by IEC 61-472 and IEEE Std 516 standards. These techniques will be coupled with electric field numerical calculations in order to foresee an extension of these techniques to live works with non conventional tools.