Lightning damage prevention

[Kangan (imported)]

Does anybody have any experience with preventing lightning damage? My metal building just took a direct hit today, and all sorts of unlikely electronics blew out, but not my computer and the DSL Internet line which is the usual victim. All sorts of video equipment is damaged. $$$ Ouch!

I've got commercial grade surge suppressors on everything, power line, phone line, video cables, you name it. There are also multiple ground rods bonded to the power and telephone protectors, but I have individual chips blown at random on several circuit boards. What a mess.

I guess a direct hit will raise the local field potential and jump the lightning arrestors. I knew I was in trouble when I heard a big ZAP and most of my video monitors went to blue screens.

Oh yeah, I have a $1000.00 deductible on my homeowners insurance.

[kristoff]

Does anybody have any experience with preventing lightning damage? My metal building just took a direct hit today, and all sorts of unlikely electronics blew out, but not my computer and the DSL Internet line which is the usual victim. All sorts of video equipment is damaged. $$$ Ouch!

I've got commercial grade surge suppressors on everything, power line, phone line, video cables, you name it. There are also multiple ground rods bonded to the power and telephone protectors, but I have individual chips blown at random on several circuit boards. What a mess.

I guess a direct hit will raise the local field potential and jump the lightning arrestors. I knew I was in trouble when I heard a big ZAP and most of my video monitors went to blue screens.

Oh yeah, I have a $1000.00 deductible on my homeowners insurance.

Do you have actual lightening rods on the building's roof.... with leads to ground rods buried 6-10 feet into the ground? The rods should be the very highest point of the building...

[Robby (imported)]

Do you have actual lightening rods on the building's roof.... with leads to ground rods buried 6-10 feet into the ground? The rods should be the very highest point of the building...

Kangan,

Here is a site you might check out: Lightning Rods (http://www.lightningarrestors.com/parts1.html)

[Kangan (imported)]

Lightening rods? To reduce the weight of the building?

No, I don't use lightning rods as they attract lightning! I do have lots of ground rods everywhere and bonding to all the power neutrals, etc. Unfortunately I'm located near a high ridgeline and the rock is only about 6' down (2 meters). There are some exposed outcrops nearby. The lightning just loves to hit the rocks and the resulting induced voltage surges destroy my electronics.

I've spent most of the day trouble shooting and replacing things. I've got random damage in all sorts of equipment. Looks like the only answer is to relocate my electronics lab. We get a direct hit about once or twice year on the average.

[Testman (imported)]

Ground rods in rocky ground are known to not work as well unless they are exceptionally deep into the ground. I have heard of electricians having to go down as far as 30 - 40 feet just to reach a good ground.

But if the building took a direct hit, then I don't think even the best ground will prevent delicate circuitry damage. I would maybe look into a lighting rod so that if lighting were to strike your building, it wouldn't really hit the building but instead the lightning rods as they will be higher than the building and lightning goes for the highest point. But if the lighting has the capability if messing up your stuff without even hitting the building directly, then I would take a look at the grounding rods you have. Are they connected to each other? In not, they should be as when lightning strikes the ground near by, there is a difference in voltage across all the ground rods and this will mess stuff up. If they are all connected, the voltage is equaled out among all ground rods. I hear that 95% of the lighting that strikes people isn't even a direct hit but instead hits the ground near by and each leg takes in different voltage levels therefor allowing the electricity to go in the body and stop the heart. Lighting rods are much the same.

[Kangan (imported)]

One of the main problems that I have is that there are two building connected by buried cables on several acres of land. There are commercial (telephone company type) lightning arrestors on most of the cables where they enter the buildings. I think there are a total of 15 ground rods at all buildings and the intermediate junction boxes. Most are bonded together, but since the distances exceed 100' to 200' between rods you can get a large voltage drop under lightning conditions.

The telephone company told me that If I could figure out how to control the lightning damage, they would like to know how I did it. This morning, I saw 2 trucks at the Central Office, so they got some damage in the same storm, although my phone line and DSL was okay. So it would appear that even the experts are stumped.

Thanks for your input. So far I am out about $1500 worth of equipment.