: Knowledgebase

A Bad Ground Can be Very Expensive in a Lightning Storm!

If you have good lightning protection for your telephone equipment, but your equipment continues to blow up after a storm, you probably have no ground or a bad ground.

Most lightning damage is caused by high voltage, which a lightning protector sends to ground. If you don't have a good ground, you don't have lightning protection - even if you bought the best you could find (like ours!).

In a place like Chicago where there is ordinary dirt almost everywhere a good ground is pretty easy to get. The electrician drives an 8-foot ground rod into the dirt right outside where the main circuit-breaker panel is and runs a heavy gauge wire from the ground rod to the metal box for the panel.

The ground is then carried to all the outlets in the building through the conduit attached to the metal circuit-breaker box, through the green ground wire put in most conduits (usually not for light switches), and on the ground wire in Romex when the local authorities don't require conduit.

Sometimes the electrician forgets to attach the big gauge wire to the ground rod or to the metal box inside. If you're not sure, it's worth going to look for your ground rod to see if the wire (or big braided wire) is attached - or just hanging loose?

The real problem comes when the earth around a building isn't just plain dirt. If it's rocks, gravel, sand or clay, those materials don't conduct electricity as well as nice moist dirt - and you probably have a bad ground.

A bad ground can get really expensive, and no one likes replacing the same equipment over and over!

For more details on grounding, see our Tech Bulletin on Electrical Grounding.

For related products, see our Lighting and Surge Protectors for Voice and Data page.