What is the conductivity value of concrete?
Sent from my iPhone
> On Jan 21, 2015, at 9:07 AM, Paul Plants <w3plp@verizon.net> wrote:
>
> Please use the correct tool not a ohm meter but a merger.
> Paul
> W3PLP
>
> Sent from my iPhone 6 plus
>
>> On Jan 21, 2015, at 8:29 AM, Patrick Greenlee <patrick_g@windstream.net>
>> wrote:
>>
>> I have a triangular tower with legs on 14 ft centers, yes, 14 feet, not
>> inches. I built it with three separate concrete foundations, one per leg.
>> It is currently tilted over so one leg is not touching its concrete embedded
>> mechanical connection/mount.
>>
>> It would seem that if I take an ohm meter reading between the unconnected
>> leg's mount and one of the other mounts I will be getting a valid estimate
>> of the Ufer ground quality of my tower installation's foundations. It could
>> be argued that I am actually measuring two Ufer grounds in parallel as two
>> of the attachment points are bridged together by the tower. I suppose I
>> will also unbolt one of the hinged legs so I can measure independently from
>> the non hinged leg mount to each hinged mount in turn.
>>
>> There is plenty of rebar in the foundations. The rebar cages are welded
>> with allowances for the effect of welding on rebar (welded at ends and
>> overlaps so no structural degradation.) Each leg's foundation has three
>> each pier holes augered with a 12 inch tractor mounted auger. I moved the
>> tractor a little while augering to get a larger hole. There is rebar in each
>> pier hole and a rectangular cage connecting the three holes. All rebar is
>> welded so there is good conductivity throughout the rebar armatures.
>>
>> Each set of three pier holes is topped by a 2'x2'x7' horizontal concrete
>> beam with an extensive rebar cage that is well connected by welding to the
>> rebar in the augered holes. All rebar is at least 2 inches (typically 3)
>> from the dirt/concrete interface.
>>
>> Am I missing something? Will a simple ohm meter test give a reasonable
>> measure of Ufer ground quality, sufficient to decide the question of whether
>> or not multiple copper clad ground rods need to be installed and
>> interconnected?
>>
>> Is it too much of a leap of faith or otherwise to assume the inter-leg
>> resistance is an adequate predictor of tower mount to Mother Earth
>> conductivity?
>>
>> Just write your opinion on the back of a US $20 bank note and mail to my QSL
>> address in QRZ.com including a SASE if you want a receipt and or thank you
>> note.
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