10. Lightning Protection

Article 10: Lightning Protection Lightning is a natural yet highly energetic event that can strike buildings, towers, and structures, causing fires, electrical damage, and dangerous surges. A properly designed lightning protection system (LPS) helps intercept a strike, conduct the current safely to the ground, and protect people and equipment. How it works - Interception: Air terminals (lightning rods) are placed on the structure to attract and intercept external lightning flashes. - Conduction: Metallic down conductors carry the strike from the air terminals down the exterior of the building. - Grounding: The down conductors connect to a grounding system that disperses the current into the earth with minimal resistance. - Bonding and protection: Metalwork and electrical/telecommunications systems are bonded to maintain a common potential, and surge protection devices (SPDs) may be installed to protect sensitive equipment from residual surges. Core components - Air terminals or rods: provide points of interception. - Conductors: route the current from the interception point to the ground. - Grounding system: electrodes or a ground array that dissipates current into the earth. - Bonding/earthing: ensures all metal parts and services are at the same electrical potential. - Surge protection devices: installed at service entrances to limit overvoltages reaching equipment. - Connectors, clamps, and mounting hardware: hold the system together securely. Design and installation considerations - Risk assessment: evaluate building type, height, occupancy, contents, location, and soil conditions (soil resistivity) to determine the level of protection needed. - Coverage and layout: ensure roof structures, tall features, and sensitive areas are adequately protected; distribute air terminals so a strike is intercepted efficiently. - Routing and grounding: plan down conductors and the ground system to minimize impedance and interference with electrical services. - Compatibility: coordinate with existing electrical, telecom, and plumbing systems; use proper bonding to avoid potential differences. - Standards: refer to recognized guidelines such as IEC 62305 (Lightning Protection Standards) or NFPA 780 (in applicable regions) and follow local codes. - Maintenance planning: include regular inspections and tests as part of building upkeep. Maintenance and inspection - Visual checks: look for damaged or corroded conductors, loose clamps, or damaged air terminals, especially after storms. - Connection integrity: verify bonds to metalwork and to the grounding system remain secure. - Ground resistance: periodically test earth resistance to ensure the grounding system remains effective. - Documentation: keep records of inspections, tests, and any repairs or replacements. Safety notes - Only qualified electrical professionals should design, install, or modify an LPS. - Work should be coordinated with building power systems and following local safety regulations. - An LPS reduces but does not eliminate risk; SPDs and proper electrical protection remain important for equipment safety. Bottom line A well-planned lightning protection system helps shield lives, structures, and critical equipment from lightning damage. It combines thoughtful design, robust grounding, proper bonding, and maintenance to provide effective protection aligned with recognized standards. If you’re considering LPS for a building, consult a qualified lightning protection specialist and refer to applicable standards to determine the appropriate level of protection.