Evaluation of Lightning Protection Systems at Telecommunications Tower Sites in Nasarawa State

This study evaluates the adequacy of lightning protection systems at mobile telecommunications tower sites operated by major network operators in Nasarawa State, North Central Nigeria. Nasarawa State experiences one of the highest lightning flash densities in Nigeria, and telecommunications tower sites are particularly vulnerable to direct lightning strikes and induced overvoltages due to their elevated structures, sensitive electronic equipment, and remote locations that preclude rapid maintenance response. An assessment was conducted at 18 tower sites belonging to three major operators across Lafia, Keffi, and Akwanga Local Government Areas. The assessment protocol followed IEC 62305 and ITS Annex recommendations, covering air termination systems, down conductor continuity, earth termination system resistance, surge protective device installation and condition, bonding of cable screens and equipment chassis, and site maintenance records. Earth resistance was measured at each site using the fall-of-potential method. Results show that earth resistance exceeds the 10-ohm target at 11 of the 18 sites, with the highest readings at sites on rocky laterite terrain. Surge protective devices are absent or expired at 7 sites. Down conductor connections are corroded or mechanically damaged at 4 sites. Equipment bonding is incomplete at 12 sites. Seven sites have no documented lightning protection maintenance visit in the preceding 24 months. The high frequency of surge-related equipment damage reported at poorly protected sites correlates with the assessment findings. Recommendations include a structured annual inspection programme and standardised site protection specifications across all operators. Keywords: lightning protection, telecommunications tower, surge protection, earth resistance, Nasarawa State.