Lightning Protection Systems
A lightning protection system gives lightning a safe path to the ground instead of through a building, its wiring or its people. Tall buildings, towers, churches, tanks and many other structures have them. Installers and maintenance workers need to understand them.
- Installers
- Roofers
- Facility Maintenance
Parts of a system
- Air terminals (lightning rods): points on the roof that intercept strikes.
- Conductors: heavy cables that connect the air terminals and run down the structure.
- Grounding electrodes: rods or plates in the earth that disperse the current. See Grounding & Bonding.
- Bonding to metal parts, pipes and electrical grounding so voltage differences do not arc across.
- Surge protective devices on power and data lines to protect equipment.
Systems are designed and installed to standards such as NFPA 780 and UL 96A, often by certified installers.
Why it matters for workers
- Do not cut, remove or paint over conductors, air terminals or bonds. Roofing, siding, HVAC and antenna work can damage or disconnect the system. Report and repair breaks.
- When a strike occurs, dangerous voltage can appear on the structure and near ground rods and conductors. Do not touch or stand near conductors, downspouts or metal during a storm.
- Hot work or drilling can hit the conductors.
- Do not attach ropes, anchors or lifelines to lightning protection parts unless designed for it.
Working during storms
- Do not work on roofs, towers or tall structures when thunderstorms are in the area. Use the 30-30 rule. See Lightning Strike Response.
- Lightning protection does not make a structure a safe shelter for workers on the roof or outside.
- Stay out of open fields, away from isolated trees and metal fences.
Inspection and maintenance
- Inspect systems regularly, after a strike, and after roof or building changes
- Check for corroded or loose connections, broken conductors, missing air terminals and damaged bonds
- Test ground resistance as the standard or the designer requires
- Keep drawings and records of the system
- Use qualified contractors for repairs
- Wear fall protection when working at roof level. See Roof Work
Standards & references
Last updated: