[R-390] Grounds

Mon Aug 3 11:41:00 EDT 2009

The electrical codes are a good place to start but really don't take 
lightning grounding into consideration because they are really two different 
schools of thought.  Even electrical code approved grounding techniques are 
no help many times because they are not designed to flow the lightning 
impulse potentials away from protected assets towards a designed ground 
field.

In electrical safety grounding....just providing an electrical connection 
(bonding) between two points meets code but in lightning protective 
grounding how that connection is made can mean the difference between it 
providing protection or being pretty much invisible to a lightning strike.

The polyphaser booklet Tisha has spoken of is really the best laymans text 
on the subject.....

Cecil
K5DL
----- Original Message ----- 
From: "rbethman" <rbethman at comcast.net>
To: "Cecil Acuff" <chacuff at cableone.net>; <R-390 at mailman.qth.net>
Cc: <wb5uom at hughes.net>
Sent: Monday, August 03, 2009 10:03 AM
Subject: Re: [R-390] Grounds

> Cecil,
>
> I do NOT ground all as well as I can - THEN - isolate the whole thing!
>
> My initial comments on the *VARYING* codes refers to localized ordinances 
> that SUPPLEMENT the NEC.  I definitely DO tie ALL grounds together.
>
> As you pointed out in YOUR post regarding the magnetic effects, 
> disconnected PCs can be destroyed.
>
> The codes here have been in a state of flux since late 2004.  The county 
> has adopted, AND made mandatory, the Internal codes for residences and 
> commercial structures.
>
> There has been a LOT of pain and financial cost to this.  Some of us that 
> had new siding put on after a heavy hail storm, have had to have it ALL 
> removed.  This is because the underlying "wrap" didn't meet the *NEW* 
> code.  Fortunately I went with 1/4" insulation made with Tyvek wrap. 
> Precisely the wrap specified by the new code.
>
> While I've done nothing electrical - antenna, ground, and the like since 
> the new code came in, I'm having a professional come out that KNOW the new 
> code, and carries it with him.
>
> Then I'll have the groundwork laid to go forward. [NO Pun Intended!]
>
> I am NOT in the county per se, BUT in a city *IN* the county.  It simply 
> adds to the confusion and frustration.
>
> I'm STILL looking for the BEST overall solution.  If it means do MORE, 
> then I will!
>
> Bob -- N0DGN
>
> Cecil Acuff wrote:
>> There seem to be two camps on grounding...
>>
>> Ground it all as well as you can and with proven techniques and then the 
>> isolate the whole thing...grounds only attract lightning.
>>
>> I can't sleep well at night knowing I did nothing because I've seen what 
>> that resulted in....
>>
>> Cecil
>> ----- Original Message ----- From: <wb5uom at hughes.net>
>> To: "rbethman" <rbethman at comcast.net>; <R-390 at mailman.qth.net>
>> Sent: Sunday, August 02, 2009 5:44 PM
>> Subject: Re: [R-390] Grounds
>>
>>
>>> This has been good reading. Thanks!
>>>
>>> I have 23 tower installations of my own and cant cout how many more of
>>> Customers sites that we take care of . Ive got some sites grounded to 
>>> the
>>> hilt and still take hits from time to time. I have others with no 
>>> grounding
>>> at all that never get hit.
>>>
>>> There was(is) this large oil company, and several years ago they had a 
>>> new
>>> Communications Manager take over. He had been in the Middle East for 
>>> years
>>> and came in to our office one day requesting a "tour" of his sites in 
>>> this
>>> area.
>>>
>>> The first words out f his mouth upon entering one of the radio Comm
>>> buildings was "Get those grounds off my equipment. I do not want  any of 
>>> my
>>> equipment OTHER THAN the shield of coax's grounded at the point of entry 
>>> on
>>> the outside of the building."
>>>
>>> And I have to say, it did not seem to get any worse afterwards and  it 
>>> is
>>> still that way today.
>>>
>>> David/WB5UOM
>>>
>>>
>>> ----- Original Message ----- From: "rbethman" <rbethman at comcast.net>
>>> To: <R-390 at mailman.qth.net>
>>> Sent: Sunday, August 02, 2009 5:19 PM
>>> Subject: Re: [R-390] Grounds
>>>
>>>
>>>> This is a "rough" play for Amateur Radio installations.
>>>>
>>>> Tisha provided EXTREMELY GOOD reference material!
>>>>
>>>> Consider it a PERMANENT fixture on my site!
>>>>
>>>> Bruce, Dave, Dave, Cecil, myself, and others have contributed 
>>>> information.
>>>>
>>>> Roger pointed out the power dissipation being measured in Joules.  Some
>>>> strikes will boggle the imagination!
>>>>
>>>> Bruce spoke of STILL losing some items.  I don't think it IS possible 
>>>> to
>>>> be absolutely safe from a strike no matter WHAT we do.
>>>>
>>>> Do YOUR *BEST*!
>>>>
>>>> Bob - N0DGN
>>>>
>>>> Bruce Ussery wrote:
>>>> > <SNIP>
>>>>
>>>> > Experience helps I imagine.
>>>> > Thanks to all for the good information.
>>>> >
>>>> > Bruce
>>>> > WA4ZLK
>>>> >
>>>> > Dave Maples wrote:
>>>> >
>>>> > All: The NEC is correct in this case.  All the grounds need to be
>>> connected
>>>> > together with large-gauge wire, so that any surge current (whether
>>> direct or
>>>> > induced) cannot set up a large potential difference between the
>>>> ground
>>>> > systems.
>>>> > <SNIP>
>>>> >
>>>>
>>>> > This is a large condensation of guidance we received from both
>>> Polyphaser
>>>> > and equipment vendors.
>>>> >
>>>> >
>>>> >
>>>>
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>>>
>>>
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>>
>>
>>
>
> -- 
> +------------------------------------------------------------------+
> |             AM Amateur Radio Operator    NØDGN                   | 
> +------------------------------------------------------------------+
> | Bob Bethman                \\\|///     " The absence of a danger |
> |                           \\ ~ ~ //      signal does *NOT* mean  |
> | rbethman at comcast.net      (/ @ @ /)      that everything is OK " |
> +-------------------------oOOo-(_)-oOOo----------------------------+
>
> 