I have a client who is building a new house. His old house was struck by lightning and burned to the ground.
For the new house, he is very interested in having lightning rods installed, to prevent the same thing from happening again.
From a liability stand point unless you have the training and UL certificate for installations of LPS systems I would not be trying to install LPS systems, there is allot of things to know and how to do them, this is not like our house wiring and is a very special field of expertize
I have heard from some that a lightning rod system attracts more lightning, thus increasing chances of direct strikes.
A Very untrue Myth, lightning strikes some things because it was in the path it was going to take anyways, it wasn't attracted by it, it just took that path because it offered a lower impedance in the path it was already taking, air planes are struck not because they attracted the lightning but because the path they flew was in the same path the lightning was taking on its way to the Earth, think of it this way, you have a storm moving along the ground, it might be a few miles away, as it is moving over the ground it is building up the electrons, when the electrons are at the point of break down in the air, it releases this energy in the stroke, where it will hit is the fact that this storm had moved over this area and the electrons had reached its peak over this point of where it hit, it was going to release it no matter what, so the lightning rod just happened to be a little better path then through the structure, if it wasn't there it most likely would have hit the structure, so in essences, it really didn't attract the lightning it just gave it a lower impedance path to the Earth.
I have also heard from others that they actually prevent strikes by draining the ions that build up in the atmosphere which cause lightning in the first place.
Nope another Myth, the Ions only build up because of the excess electrons building up in the cloud, the Ions do not stop building because of something that is connected to Earth, it is this difference of potential of electrons between the clouds and Earth that cause the Ion stream till the break down voltage reaches its peak then the lightning flashes over to Earth or up to the cloud (in a positive strike) as long as the cloud has a charge there will be a Ion stream below it as a mirror to it. Keep in mind in both the above questions, the distance between the point of the cloud and Earth can be thousands of feet, and a lightning rod only a few feet off the ground will not change the area of where it will hit, but it is only a hope the lightning rod will give it a better path for these last few feet, there are many cases and photos of when they don't, and for this reason installing LPS systems caries a high liability with it, liability insurance can be very high for doing this kind of work.
Can someone elaborate on the effectiveness of having a lightning rod system on a single dwelling? There are some trees in the yard, and the old house was burned down from an apparent strike on a tree that traveled down to the ground, and cut across the yard, then into the basement area where the fire started.
It's funny that the tree was removed, if it was in a condition to survive it might have been better to keep it, unless it was very close to the house, lightning will not travel very far in th Earth before dissipating, many believe that it will travel hundreds of feet to do damage in a house when in real life this is not true as what they experience was what is called a LEMP or a lightning electro magnetic pulse, if strong enough it can cause strong currents to be induced into the wiring of houses and network, cable, and phone loops.
it was recognized many years ago that trees can offer one of the best protection from lightning strikes as they are a natural ground rod because of the many branches of varying lengths that tend to give lightning a low impedance path, but if they are too close to a house then the magnetic pulse can still cause damage as it can even with a properly installed LPS system.
Blue spruce is one of the most used trees used in lightning protection systems and are very expensive to install.
(FYI the offending tree has been removed on orders of the lady of the property.)
Like I said above the tree took the hit because it was there not because it attracted the lightning, now the next strike can hit the house directly, with the above said there is much more then I can put into one post, and knowledge about lightning is still in the evaluation stages and there is much more to be learned, but like I said, if you are not UL certified to do LPS systems then do not put you or your company in the liability loop, because the house will be hit again, its just a matter of when, if it does and it burns down they will be looking at you and your company, I would tell them to look for a UL certified LPS installation company who specializes in LPS systems.
