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[TowerTalk] Lightning protection

To: <>
Subject: [TowerTalk] Lightning protection
From: (Eric Gustafson Courtesy Account)
Date: Thu, 4 Jun 1998 15:27:06 -0700

I used to think the same thing.  Then, one day many years ago, I
decided that I had to go up on the roof and see how this
miraculous system that kept lightning from striking the building
I was working in actually functioned.  This building was Greely
Hall on Ft Huachuca here in southern AZ.  During the monsoon
season, from our windows we could see almost daily hits to the
other surrounding buildings.  All of which were lower than Greely
Hall.  Since nothing ever happend at Greely Hall we (most of us
anyhow) assumed that we weren't getting hit.

Well, once I got on the roof and examined the lightning diversion
system carefully, I got the education that I sought.  I examined
every single lightning rod on the roof.  Every single one of them
no longer had the sharp conical point that it had when it was
installed.  All of the sharp points had been melted back to a
diameter on the cone of about 0.25 inch or a bit more.  I took a
grinder and file up the next day and resharpened five of them.
Within a month all five had been hit again and had the nice
smooth rounded melted point restored.  These melted tips were the
only evidence that lightning had touched anywhere near the
building.  The conductor carrying the current was not melted (or
even changed in any observable way) by the current flow.  Only
the part of the system that actually touched the spark plasma
(15,000 degrees C) snowed any thermal effect of the strike.

It was clear to me that the bleeding charge that the lightning
rods was doing had the effect of virtually guaranteeing that the
lightning would hit the rod and not something else.

This building was chock full of computers and sensitive solid
state electronic equipment.  None of the stuff I had to interact
with ever had any damage whatsoever.  Not even a glitch in the
operation during the strikes (much of the instrumentation ran 24

I think a more correct statement would be that these systems work
because they provide a safe spark attachment point for the strike
energy to use to find a safe conductive path to ground that
doesn't flow through people or expensive equipment.

73, Eric  N7CL

To: <>
>Date: Wed, 03 Jun 1998 22:48:19 -0500
>From: Bill Aycock <>
>I have been reading a lot of pseudo-expert opinions- and I have
>one personal observation that "Bleeding" charges does work to
>protect from "hits".
>I worked for 38 years in an explosives plant.  ALL our buildings
>had "Lightning Rods" and ground systems using BRAIDED copper
>wire networks in trenches. (The wire appeared to be about a half
>inch diameter, braided of about #12)
>With one exception, NONE of these buildings EVER had a hit- the
>exception was when a roofer cut a lead to one of the "spikes"
>and did not report it.  We found it out when we had a hit on the
>metal flue of the furnace of the chem lab. (Highest point, and
>was the location of the rod that was disconnected.)
>We had trees hit, and temporary structures hit, but NEVER had a
>hit on a "shielded " structure.  Thirty-eight years is a long
>These systems work because they change the locus of the probable
>path for a strike to another place, away from the "protected"
>building.  Thats why I threw my Mayonaisse jar away and ground
>my wires when they are not in use.
>Bill- W4BSG
>Bill Aycock   W4BSG
>Jackson County, AL
>W4BSG is "vanity" this time, but was 
>earned by exam in 1954, the first time.

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