[Elecraft] OT: Ground rods and concrete

[Rick Dettinger]

I don’t think its a myth.  In the early 1970’s, the power company I worked for was testing out some hollow reinforced concrete poles.  There was considerable concern by the line workers that the poles might be more dangerous to work on than wooden poles, in the event of an accident.  To check this, we installed one of the poles in a sub station, and wrapped a 26KV 1200 amp feeder conductor around the pole.  When the station breaker was closed, the pole exploded dramatically, with a large fireball.  The results might have something to do with moisture content in the concrete.  The results convinced us to only use the poles on transmission lines that wouldn’t be worked hot, like we did with distribution lines.  Of course, the power levels are much higher in lightening strikes.  The conduction paths should similar from encapsulated ground rods in a tower base to Earth.

73,
Rick  K7MW



> On Apr 17, 2017, at 8:32 PM, Doug Renwick <ve5ra at sasktel.net> wrote:
> 
> That myth refuses to die. I have 5 concrete tower bases with ground rods
> partially encased and never a worry about an exploding base.
> 
> Doug 
> 
> 
> -----Original Message-----
> 
> -NEVER- encase a ground rod in concrete ... especially a tower base.
> 
> As a retired 2-way radio tech, I'm aware of two towers that had to be
> re-installed because of lightening strikes exploding their concrete bases.
> 
> 73!
> 
> Ken - K0PP
> 
> 
> 
> ---
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