Re: lightning dangers

[brian whatcott <inet@INTELLISYS.NET>]

At 22:46 4/28/99 -0400, you wrote:
....
> I find it useful to think of the charge "trying to get to ground"
> anyway it can.  It "explores" various paths, sometimes zig-zagging
> around, sometimes splitting into multiple paths.  But by the time the
> strike has developed, there's no stopping it... it will go where it
> wants.
> ....
> Michael D. Edmiston

Knowlton's Standard Handbook for Electrical Engineers also has
something to say about the effects of lightning AFTER it hits
the ground. It reported that  power pylons that carried the aerial
ground wire into local ground radials eliminated most lightning
strike outages, but a power line that carried an underground wire
under all pylons continuously eliminated all outages in a ten year
 period...
   The ground resistance can be high enough to permit flashovers
from the top ground onto a live conductor, without a buried ground
 too...

Which reminds me (at the anecdotal level) that the current advice
 to folks caught outside with their hair beginning to rise in the
 electric field:
 "Crouch down, don't lie down, and keep your footprint area small
on the ground - to minimize the PD across your extremities".

  I don't recall reading of electrocution deaths in houses,
(from lightning)
though the deaths by spontaneous ignition are apparently legion
in the medical press.

 Perhaps I had better phrase that more carefully:
while deaths from electrically ignited fires are high in the U.S
and lower in Europe, electrocution deaths in domestic accidents
from electrical equipment are high in Europe and lower here:
a contrast attributed to the different line voltages
(not to mention our curious practise of securing domestic power
connections with twisted wire inside plastic cups)
  I suppose it's a case of
"If the I^2.R don't get you, the V will."

Take Care!

brian whatcott <inet@intellisys.net>
Altus OK