I was reading back on lighning protection and I remembered a
lawsuit I testified in where home owners were objecting to
the construction of a 300' tower a quarter mile from them.
They claimed the tower would attract lightning and be a
hazard to their homes.
I pointed out two things. First, lightning does not always
strike the tallest object. I've seen puncture holes in
broadcast FM antenna arrays and coax lines as far down as
50' from the top of the tower. Second, if it did attract
lightning, it would be better to have it hit the tower
where minimum damage would occur as compared to hitting
their homes.
Typically, a tall structure provides a "cone of protecion"
extending about 45 degrees about the structure. But not
always!
Here are some examples of what I've personally seen:
- While standing at the base of a 400' tower, lightning hit
an outer guy wire 100' from the ground.
- While at the 700' level of a 1,000' tower, lightning hit a
tree 500 feet from the tower.
And just last month, I was standing on my front pourch and
saw a strike in the middle of a plowed field about 1000 feet
from me. The moment it hit, I recall thinking it was in
front of a row of trees in the distance. After saying "Oh SH*T"
to myself, I looked at the spot it hit and saw a plume of
smoke or steam coming up off the ground.
Years ago, we had two strikes on two different days while
building a 500 foot tower. One hit the gin pole 20' above me
and another hit the crow's nest 5' above me.
On another tower, a storm came up from behind me and caught
me by surprise. I was at the top of the 380' tower in a strong
static field. There was St. Elmo's fire sparking off from
my tool belt and around the beacon lamp assembly - it looked
like one inch long pieces of yarn wiggling around the metal
bands of the beacon and repelled away when I tried to touch
them.
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