Lightning Protection
(reprinted with permission from Grinnell Mutual Reinsurance Company, I-80 & Hwy 146, Grinnell, Iowa 50112)

  1. Place the ground rods for the complete system at diagonally opposite corners of the building.

  2. Lightning rods less than two feet in length should have a maximum spacing of 20 feet.  Rods over two feet in length should have a maximum spacing of 25 feet.

  3. Extend ground rods into the earth to a depth of ten feet and two feet from the foundation.

  4. Bond the lightning rod system to any metal door tracks, hay tracks, or other metal objects if within six feet of the lightning rod cable.

  5. Place lead-plated air terminals (points) by chimneys to prevent deterioration.  Place air terminals (points) by other projections.

  6. Keep lightning rod systems in a good state of repair. Broken, improper, or poor lightning rod systems should be removed as the potential for damage may be greater than no system at all.

  7. Ground independently, television antenna masts, metal stanchions, feed bulk bins, and other metallic "bodies" and interconnect with the lightning rod system.

  8. Install a lightning surge arrestor on CB coax cable and TV antenna lead-in wires near the point of entry into the building and connect to an adequate ground.

  9. Install a lightning surge arrestor on the electrical system of major buildings, submersible pump motors, crop dryers, and feed and grain handling systems.

  10. Grounding metal roofs on buildings with standard size cable at diagonally opposite corners is NOT sufficient.