New view on lightning rods

[brandon7861]

I just watched a video that completely changed my understanding of lightning rods. Up until today, I assumed they were there to take a hit and redirect it to ground. That's not what they are for. Turns out, having them actually prevents the strike from happening! When the charged cloud passes over, there is a charge on the ground that follows the cloud. The sharp tips of the lightning rods dissipate this ground charge as it approaches before it can build up enough to break down the air.

Here is a link to the video I watched, and the lightning rod demonstration (using a Wimshurst generator) is at 17:22. I live on one of the highest points in our area and strong storms are common. We have three sharp-tipped lightning rods on our roof and we have never had a lightning strike here.

Has anyone here (with good lightning rods and grounding system) ever taken a direct hit?

 

[Captain Kilowatt]

Well the primary purpose is to help prevent a strike in the first place but the secondary purpose is to SAFELY shunt energy in the event of a strike. What gets me is some people's insistence that they attract lightning and that you would be safer without them. Some even claim that the incidence of a building being struck is lower without them. They fail to understand, or even listen to reason, about what happens during a strike to a building with and without lightning rod protection. PROPERLY installed lightning rods work.

 

[Captain Kilowatt]

Case in point. Several years ago a local had an Antron 99 on the end of his two story house. The radio was mounted under the cupboards in the kitchen. No lightning rods or even any for of lightning protection. Lightning struck the antenna reducing it to noting but fiberglass shards. The radio was blown out from under the cabinets, the coax cable having burned up in several places and catching fire to the house. This was probably 20 years ago but even then there was close to $40,000 damage to the house. He was lucky actually.

The barn across the road from my place was struck a few times but had ZERO damage. He had lightning rods attached and connected with HEAVY copper wire to ground.

 

[Alabama Buckeye]

LPATS, Lightning Position And Tracking Sysytem, indicate the vast majority of cloud to ground lightning strikes are negative discharges.

Negative grounded lightning rods, and antennas present available negative ground (pun intended) leaders to positively charge lightning strikes only.
Negative doesn't attract negative.
A nearby positively charged tree or ungrounded structure is more likely to get struck.

Then there is positively charged lightning which occurs in the near anvil heights of storm clouds; and, are most often discharged to the lower altitude negatively charged bases of nearby and distant storm clouds.
But, not always. Your negative grounded antenna is a potential target.

Brandon, Lightning Rods don't come with a guarantee.

There is also In-Cloud lightning, like self-flagulating.