RE: Lightning

["Keith Doxey" <ukha@xxxxxxxxxxx>]

Hi Chris

> but 'wondered it anyone had gone so far as
> putting-in lightning conductors ... we rapidly shut-down all computers
&
> h-fi & pulled all the plugs, this time ... but if we'd had
'conductors,
> would we have been able to carry-on & avoid all that ?
>

Lightning conductors are primarily intended to protect buildings that are
at
high risk of being struck in the first place eg tower blocks, churches with
high steeples etc and buildings/structures where damage to electronic
equipment would be catastrophic eg Telephone exchanges, data centres, radio
stations and transmitters.

The amount of energy in a single lightning strike is immense and if we
could
harness, store and distribute that energy we would have free power due to
the number of storms that are always in progress around the globe.

Next time you are near a large building that has a lightning conductor take
a closer look at it.... it is connecte to earth by copper strap about 5mm
thick and upto 50mm wide. Even then they can be melted by the energy
disipated by a strike. The actual conductor has to be the highest thing on
the building to ensure that it is hit before any other part of the building
and often there are a network of copper strips running along the ridge of
the roof.

Even when you have a lighting conductor you are not safe. Thre was an
article in one of my magazines several years ago about a church that got
struck. Lightning travelled down the conductor but due to a poor earth the
lightning then jumped across onto the mains wiring of the building. Every
electrical device was destroyed.

Out of interest they decided to investigate how bad the destruction was and
disassembled and electronic organ and test the components. Every transistor
and IC was totally destroyed.

A proper lightning conductor will cost an awful lot of money and may never
be needed. If needed it may not be totally effective. My advise would be to
spend the money on insurance cover that will replace your equipment if it
does get damaged.

We once had to deal with a solicitor who would sign the bill for lighting
damage to his phone system as there were no obvious signs of damage so how
could it be proved that lighting was to blame. He was told that we had seen
identical faults in previous storms and the number of simultaneously
reported faults just after a major storm also confirmed that analysis. He
was told that he could pay to have the chips inspected in a laboratory (at
his expense) to prove the cause of the failure... or he could go to the
office next door and look at the black mark on the wall where their phone
system used to be!!!!

HTH

Keith