[TowerTalk] Tower grounds near Underground Utilities?

Thu, 28 Jan 1999 16:45:49 -0500

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At 10:41 AM 1/28/99 -0700, you wrote:
>
>
>Hi Jonathan,
>
>The answer to your question about how much ground is required to
>dissipate a strike safely is: "It varies".  
snips
>In short, you are asking the wrong question.  You should be
>asking: "How do I configure my installation to prevent damage
>from this source?".

>
>You can have any proximity you desire so long as the system is
>bonded together with a fast enough path.  If the bonding is
>adequate, voltage differentials between adjacent conductors are
>not permitted to rise to the level that will cause a plasma
>channel to take a shortcut across the gap. 

more snip..

 Please consult the Lightning Protection Code
>(NFPA-78 and later versions) for information about how to
>properly bond the system together and tie it into earth.
>
>73, Eric  N7CL

Let me begin by saying I have a high regard for Eric and his apparent grasp of
a wide range of technical issues. I would only suggest there is an additional
text that should be read that would be quite instructive. Perhaps you already
are aware of it, the IEEE EMERALD book. This is the definitive text on Powering
and Grounding Sensitive Electronic Equipment. IEEE Std 110-1992.  I trust you
will find this text enlightening.

73,
Bruce  (AA8U)
Sr. Power Quality Specialist 
Consumers Energy
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<html>
At 10:41 AM 1/28/99 -0700, you wrote: 
&gt; 
&gt; 
&gt;Hi Jonathan, 
&gt; 
&gt;The answer to your question about how much ground is required 
to 
&gt;dissipate a strike safely is: &quot;It varies&quot;.&nbsp; 
snips 
&gt;In short, you are asking the wrong question.&nbsp; You should 
be 
&gt;asking: &quot;How do I configure my installation to prevent
damage 
&gt;from this source?&quot;. 
 
&gt; 
&gt;You can have any proximity you desire so long as the system is 
&gt;bonded together with a fast enough path.&nbsp; If the bonding 
is 
&gt;adequate, voltage differentials between adjacent conductors are 
&gt;not permitted to rise to the level that will cause a plasma 
&gt;channel to take a shortcut across the gap. 
 
more snip.. 
 
&nbsp;Please consult the Lightning Protection Code 
&gt;(NFPA-78 and later versions) for information about how to 
&gt;properly bond the system together and tie it into earth. 
&gt; 
&gt;73, Eric&nbsp; N7CL 
 
Let me begin by saying I have a high regard for Eric and his apparent
grasp of a wide range of technical issues. I would only suggest there is
an additional text that should be read that would be quite instructive.
Perhaps you already are aware of it, the IEEE EMERALD book. This is the
definitive text on Powering and Grounding Sensitive Electronic Equipment.
IEEE Std 110-1992.&nbsp; I trust you will find this text
enlightening. 
 
73, 
Bruce&nbsp; (AA8U) 
Sr. Power Quality Specialist 
Consumers Energy</html>

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