[Elecraft] FAR OT: Grounding and lightning

[David Gilbert]

If that was actually the case, I would surmise that the "ground rods" 
were not connected to a proper rebar cage (i.e., Ufer ground) that would 
normally be able to able to distribute the lightning current over a 
sufficiently large surface.  Simply putting a couple of ground rods 
inside a concrete base is folly, but that is not at all the same as 
having a proper Ufer ground inside the base, nor is it the same thing as 
running a conductor through the base to a sufficient external ground.

It does not advance the technical competency level of our hobby to make 
broad generalizations based upon narrow and poorly defined anecdotal 
instances.

Dave   AB7E



On 4/25/2018 3:10 PM, Ken G Kopp wrote:
> I should have been more specific in suggesting that grounds that
> might end up carrying a lightening charge not be run through concrete.
>
> The following is from personal "real world" experience.
>
> I know of two specific cases where tower bases were blown apart by
> lightning hits to the towers because ... in the interest of "neatness" ...
> their ground rods were -inside- the concrete bases.
>
> These two events took place in the Tampa Bay (St. Petersburg) area
> of Florida.  The Tampa Bay area has the distinction of having the highest
> number of lightening strikes in the western hemisphere, BTW.
>
> I worked aboard a USC&GS (NOAA) ship at the time and we did a lot of
> lightening-related research.  Picture flying a balloon-borne wire to
> deliberately
> attract lightening!
>
> Concrete is rarely "dry" even after years of "curing".  The dampness becomes
> steam that's instantly created by the current from strike flowing through
> the
> ground that's -inside- the concrete.  This steam becomes part of the
> explosion.
>
> 73!
>
> Ken Kopp - K0PP
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to xdavid at cis-broadband.com
>