"PoP" wrote in message
...
On Sun, 26 Oct 2003 03:39:55 -0000, "gandalf"
wrote:

With a lightning conductor you can be reasonably sure that you will get
struck.
Again and again. So I think a risk assessment might be in order because
the
fright you get when you do get struck is not pleasant.

Just wondering aloud - there is an awful lot of instantaneous power
transferred when lightning makes contact. I imagine that this would
fry any puny lightning conductor on the first occasion.

Presumably lightning conductors are designed such that they can carry
the enormous load the instant of a second?

If a lightning conductor is struck, it has failed in its main purpose. What
it is supposed to do is to cause a gradual discharge of the potential
difference between earth and cloud, thus preventing a high enough charge
from building up to create a strike. A proper installation has a number of
air terminals, to create a brush discharge effect, and numerous conductors,
to distribute the load across as wide an area as possible. While copper tape
is widely used, some engineers prefer iron, because it has a higher
impedance.

Colin Bignell