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Re: [TowerTalk] Fw: w7ekb & ground rods

To: towertalk@contesting.com
Subject: Re: [TowerTalk] Fw: w7ekb & ground rods
From: Patrick Greenlee <patrick_g@windstream.net>
Date: Mon, 19 Jan 2015 12:47:02 -0600
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Yes, but then all concrete in contact with moist dirt is conductive. Conductivity is improved by increased area of contact and the Ufer ground has huge area compared to even dozens of driven rods.

Patrick  NJ5G


On 1/19/2015 11:30 AM, Brian Carling wrote:
I have not heard of this concrete ground before. Is it made with conductive 
concrete?

Best regards - Brian Carling
AF4K Crystals Co.
117 Sterling Pine St.
Sanford, FL 32773

Tel: +USA 321-262-5471




On Jan 19, 2015, at 10:19 AM, Jim Lux <jimlux@earthlink.net> wrote:

On 1/18/15 9:53 PM, Kelly Taylor wrote:
It seems to me a valid question to ask on this thread: Do you gain anything
by, for example, drilling a hole to get a ground rod deeper?

If you think about it, the answer might not be so simple.

The point of a ground rod is to maximize electrical contact with the ground.
If you have to drill 48 inches of an eight-foot rod and don't employ some
kind of conductive filler (concrete, bentonite, etc.) to bond the rod to the
rock, how much better off are you than just putting in a 48-inch rod? Even
if you do use bentonite, is rock a good connection?

If that's the case, what would be wrong with cutting the eight-foot rod into
two 48-inch rods and driving them 96 inches apart?

The point of eight- or ten-foot ground rods is to get eight or ten feet of
contact area, not necessarily to get eight or ten feet deep, yes?

Yes, and two short rods would work as well, if not better, than 1 big rod.

However, there is a potential depth related issue: soil moisture varies a lot 
in the first few feet, and in a lot of places, the chemical composition of the 
soil changes (top soil vs subsoil).  That's not really addressed in the 
building code, though.

For what it's worth, the reason the code expresses a preference for Ufer 
grounds(concrete encased grounding electrodes) is just this sort of problem.  A 
big block of concrete 20 feet long and a foot square is going to have a lot of 
contact area with the surrounding soil, in a lot of places, so local anomalies 
of dry or loosely compacted soil aren't going to be as big a problem.



Just curious on all this.

73, kelly
ve4xt


On 1/18/15 10:04 PM, "Bill Aycock" <billaycock@mediacombb.net> wrote:

-----Original Message-----
From: Bill Aycock
Sent: Sunday, January 18, 2015
7:23 PM
To: Ken
Subject: Re: [TowerTalk] w7ekb & ground rods

Ken--
I was once
told (Unofficially) by a power line guy that the length was more
important
than depth, and a rod driven at an angle was often the only option
when rock
was a problem.
However, Mr. Murphy ruled against me and I only knew I had a
rock problem
when I had only about 8" left to go.
Bill--W4BSG

-----Original
Message-----
From: Ken
Sent: Sunday, January 18, 2015 7:00 PM
To:
maflynn@theflynn.org
Cc: towertalk@contesting.com
Subject: Re: [TowerTalk]
w7ekb & ground rods
If I may ask, what¹s the ³appropriate tool² when you have
a rock layer 40²
down?  i tried a hammer drill, waste of time.  I rented an
SDS-MAX hammer
and I got one in all the way, four others only made it most of
the way.   So
what is the recommendation?

Ken WA8JXM

On Jan 18, 2015, at
7:46 PM, Martin A Flynn <maflynn@theflynn.org> wrote:

Ran this past one of
the code enforcement guys in the county. Surprising
response:

"We make
you buy a UL listed panel board and breakers -  what makes you
think you
can build a grounding system that is equal to UL *and*  be able
to prove it
in court if there is a problem? Buy the listed rod(s) and
drive them with
the appropriate
tool"
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