Transferred Potential—A Hidden Killer of Many Linemen

The causes of electrical accidents which occur during maintenance of power lines are sometimes not traceable. Unfortunately, a grounding practice which has been widely adopted in the utility industry in India, U.K., and some other countries unintentionally causes so many fatal accidents every year. The conclusion was arrived after analyzing some fatal accidents. This practice of protective grounding is still continued by many distribution companies without realizing the hazards involved. For de-energized line maintenance, grounding the line at source end is commonly practiced for the purpose of personal protection. This paper explains how this safety practice turns into hazard by transferring the substation ground grid potential to the worksite and why this transferred potential cannot be controlled by any means in three-wire overhead distribution systems which run with no separated ground wire. This paper suggests the solution to avoid the transferred potential and to describe it in IEEE Std. 1048-Guide for Protective Grounding of Power Lines, IEEE Std. 80-2000-Guide for Safety in AC Substation Grounding, British Std. 7430-Code of Practice for Earthing, and Indian Std. 3043-Code of Practice for Earthing to bring an end to the accidents caused by this safety practice.