[TowerTalk] Ground Rod Myths?

[Mike Fahmie via TowerTalk]

It all depends on the conductivity of the concrete versus the local soil.

Ufer grounds excel in soils with poor conductivity (dry sand is an extreme case), but it makes no sense to wrap your ground rod in a material that has poorer conductivity than the soil surrounding it.  Concrete can be a much better conductor than poor earth but worse than earth with good conductivity.

I chose the Ufer path because my 'soil' is dry hardpan that resisted ground rod drivers and I felt that the large contact area of the concrete would makeup for the soils poor conductivity.

-Mike-
WA6ZTY



>________________________________
> From: Roger (K8RI) on TT <K8RI-on-TowerTalk at tm.net>
>To: towertalk at contesting.com 
>Sent: Thursday, April 24, 2014 8:14 PM
>Subject: Re: [TowerTalk] Ground Rod Myths?
> 
>
>On 4/24/2014 1:36 PM, Brian Amos wrote:
>> I have the equipment to drill a 6 inch hole through just about
>> anything, what if I placed my grounding rods in concrete or grout?
>
>I would think it wouldn't hurt.  It might act as a small UFER ground. 
>increasing the contact area of 20 inches Vs 1.9 inches or almost 11 
>times the area of the single ground rod.
>
>How well that'd hold true? I don't know.
>
>73
>'
>Roger (K8RI)
>
>
>
>> Would that help or hurt the grounding?  I do have a ground resistance
>> meter I use for work for providing soil resistance values for
>> grounding communication towers and equipment so I could test it I
>> suppose, but I usually like to know what I'm getting myself into.  I
>> have seen them drive a steel lathe (about 3/4 inch in diameter) into
>> slightly weathered bedrock with a post pounder on a bobcat.  The
>> cobbles and boulders just cause it to move a bit to the right or left.
>>   Of course the commercial towers I do the foundation design for
>> usually have a grounding grid surrounding them.  I am tempted to see
>> if one of the tower engineers will design my grounding system with a
>> similar system, they tend to suffer little if any damage from
>> lightening, and being on mountain tops I am sure they are struck quite
>> often.
>>
>> Brian
>> KF7OVD
>>
>
>
>_______________________________________________
>
>
>
>_______________________________________________
>TowerTalk mailing list
>TowerTalk at contesting.com
>http://lists.contesting.com/mailman/listinfo/towertalk
>
>
>