[time-nuts] thoughts on lightning arrestors

[Chris Albertson]

Lightening arresters don't have to handle that much energy.

When a strike hits a mast with an antenna on it the current divides.  Most
of it should go straight down the tower or mast into the ground.  This is
why the structure is bonded to a grounding system using a straight line
path with ground rods directly under the tower

Some of the current finds it's way to the coaxial shield and flows to
ground at he bulkhead coupler that is also grounded.

Some fraction actually goes into the center conductor of the antenna lead.
This is what the lightening arrester has to clamp and shunt to ground.  It
is a very small part of the total energy from the strike.

The tree exploded because it contained water that was heated to vapor very
quickly by he current.  If the tree had a ground wire from top to bottom
the strike would have been uneventful.


On Thu, Nov 27, 2014 at 10:40 PM, Mark Sims <holrum at hotmail.com> wrote:

> Bark effect? ;-)
> Lightning hit a tree behind where I lived and three other trees near it
> also exploded...  you ain't gonna arrest a direct lightning strike.
>



-- 

Chris Albertson
Redondo Beach, California