A lightning protection system is simple in concept: give lightning a safe, low-resistance path from the roof to the ground so it doesn't take a destructive path through your building. Doing that well depends on several parts working together.
1. Air terminals (lightning rods)
Air terminals are the rods mounted on the roof, typically along ridges, at corners, and on chimneys and other high points. They provide a preferred point for a strike to attach. Their placement and spacing depend on the roof's shape, pitch, and size, which is why systems are designed for each building.
2. Conductors
Heavy copper or aluminum cables connect the air terminals to each other and run down the building to the ground. Conductors are routed to avoid sharp bends, which lightning current doesn't follow well, and to provide more than one path to ground so current divides and dissipates.
3. Bonding
Lightning current can jump, or side-flash, from the system to nearby metal objects like gutters, vents, HVAC units, antennas, and metal roofing. Bonding connects those objects to the system so everything stays at a similar electrical potential and current doesn't arc through the structure.
4. Grounding
Grounding electrodes, usually ground rods but sometimes ground rings, plates, or other layouts, deliver the current into the earth. Soil matters a great deal. Texas has everything from wet Gulf Coast clay to expansive Blackland Prairie clay, shallow Hill Country limestone, and dry West Texas caliche, and each calls for a different grounding approach. The grounding system is typically bonded to the building's electrical and other grounding systems so they share a common ground.
5. Surge protection
Even with a perfect path to ground, a strike creates surges that can enter the building through power, phone, cable, and data lines, and a nearby strike can do the same. Surge protective devices at the electrical panel and on communication lines limit those surges before they reach your wiring and electronics.
Why design and installation quality matter
A system with missing connections, sharp bends, poor grounding, or unbonded metal can fail to protect the building when it's needed. That's why the industry relies on standards such as NFPA 780, and why an installer should design the system for the specific building and inspect it once installed.
Maintenance
Systems can be damaged by storms, disconnected during roof work, or corroded over time, especially near the coast. Periodic inspections keep the system working as designed.