On Bonding and Grounding of Metal Fences

This paper examines the electrical safety challenges associated with metal chain-link fences, focusing on their classification as either Exposed-Conductive-Parts or Extraneous-Conductive-Parts and the conditions under which grounding or bonding is required. In high-voltage installations, such as supply stations and substations, bonding fences to the facility's grounding system is essential to achieve equipotentiality and mitigate hazardous touch voltages. In contrast, for fences surrounding private properties where energization risks are generally lower, routine bonding may, in certain circumstances, introduce additional risks by enabling fault current propagation. The study also presents a risk assessment methodology for lightning strike hazards, demonstrating that the safe length of unprotected fences is strongly dependent on the local lightning flash density and installation environment. In regions with high flash densities, even relatively short fence spans may exceed safe thresholds unless lightning protection measures, such as air terminals and intentional grounding systems, are implemented. The findings underscore the need for site-specific evaluations to determine appropriate bonding and grounding strategies that balance safety with practical design considerations.