[TowerTalk] Fwd: Grounding connection to tower legs

Tue Oct 17 07:36:08 EDT 2017

-1.- When you do the quarterly service on your towers, then you refresh 
the copper flakes...
-2.- Go to ...http://www.kc4pe.com/amateurshack.htm .... and hit the 
link on "Tower grounding" or just scroll to the bottom of the 
site..basically it's 5" copper ribbon fed into a 13" X 2" slotted copper 
bar, which is then secure to a folded strip of stainless steel which is 
clamped to a horizontal tower bar.....I have also added a 2 inch piece 
of copper ribbon in the mix then ran to each tower and secured it using 
the SS as a buffer...

Bill --KC4PE

On 10/16/2017 1:28 PM, Jeff wrote:
> I have finally succumb to the wisdom of the board and ordered up some 
> commercial Penn Union clamps which have 3/8" u-bolts and a 
> comparatively huge bronze clamp.  They are sized for my intended wire 
> as well.  I'm not sure but they may also provide a flat compressive 
> fit for strap. Unfortunately I had to break into my son's piggy bank 
> to pay for them but someone mentioned insurance claims and I suppose 
> that is a pretty good point as the towers will definitely be the 
> tallest thing around.
>
> I think the consensus on the antioxidant use is mixed.  I wonder how 
> well that stuff would hold up over years of seasonal weather exposure. 
> Definitely would not hurt but it's fundamentally a mix of copper and 
> grease and it seems like the grease would be worn away by the weather 
> over time.
>
> 73/jeff/ac0c
> www.ac0c.com
> alpha-charlie-zero-charlie
>
> -----Original Message----- From: Ward Silver
> Sent: Tuesday, October 17, 2017 12:56 AM
> To: Billy Cox
> Cc: Reflector
> Subject: Re: [TowerTalk] Fwd: Grounding connection to tower legs
>
> A quick reply - yes, the stainless steel shim clamps can be used *in
> some circumstances* but my understanding from Polyphaser folks was these
> are not to be used as primary grounding clamps for heavy conductors.
> These are just to attach some kind of light-duty strap or wire (or
> braid!) to a galvanized pipe, tube, or rod.  For the main ground
> connection that is intended to handle the lightning surge, you have to
> use the heavy-duty clamps.
>
> A good source of information is usually an electrician or tower
> installer who knows what the local codes are and any special
> circumstances that require particular hardware, coatings, etc.
>
> 73, Ward N0AX
>
>
> On 10/16/2017 11:13 AM, Billy Cox wrote:
>> Good Morning All, and I am reading along this with interest given 
>> past posts
>> as to the what/where of properly using worm-gear type clamp products.
>>
>> Ward ... please note that some suppliers DO seem to suggest their use?
>>
>> http://www.polyphaser.com/products/grounding-and-bonding
>>
>> On the other hand, and from the daily calls/email here as to "can I 
>> do this or
>> should we do that?" with various clamp products, there are many many 
>> design
>> factors that really need to be properly considered with this topic.
>>
>> So given the various present unknowns here (clamp type, bandwidth, 
>> thickness,
>> type of materials and so on) I can't fully agree or disagree with 
>> your statements
>> as to the use of worm-gear clamps for such applications. But it is 
>> interesting ...
>>
>> Basically this topic comes down to risk management. And as one who in 
>> times
>> past did things poorly and suffered the consequences in the form of 
>> canceled
>> insurance, and extra work/time/investments to overcome the root 
>> causes ....
>>
>> I would suggest each person understand their specific risks, study 
>> appropriate
>> sound technical information (such as Ward's book!) to decide what to 
>> do there.
>>
>> 73 de Billy, AA4NU
>>
>> Disclaimer if needed: Product Manager - Ideal Clamp Products.
>>
>> ------------------------------------------------------------------------
>> *From: *"Ward Silver" <hwardsil at gmail.com>
>> *To: *"Reflector" <towertalk at contesting.com>
>> *Sent: *Monday, October 16, 2017 7:26:02 AM
>> *Subject: *Re: [TowerTalk] Fwd: Grounding connection to tower legs
>>
>> > Why would the hose clamp blow apart? I have used this method for 
>> decades
>> and have had multiple direct lightning strikes.
>>
>> The mechanical forces on a conductor carrying kilo-amp currents from a
>> lightning strike can be extreme - many pounds per foot of conductor. 
>> (This
>> is described by Ampere's Force Law.) That's why codes require ground
>> conductors for lightning rods and antennas to be secured to a 
>> building or
>> support structure. (This was news to me, too.)
>>
>> Basically, the conductor experiences a huge jerk which would destroy 
>> either
>> the conductor or whatever is trying to secure it - like a hose 
>> clamp.  So
>> it would be more accurate to say that the hose clamp is not rated to
>> withstand the force experienced by the ground conductor and is not blown
>> apart by the current.  It's the mechanical force.
>>
>> If hose clamps have been used and the tower has taken hits without 
>> damaging
>> them, then the ground conductors are not for whatever reason carrying
>> enough of the current pulse to generate damaging forces.  Or maybe the
>> configuration of the conductor was such that the force was weaker 
>> than it
>> could be.  i.e. - you got lucky :-)
>>
>> I'm no different in that I've used hose clamps over the years for 
>> similar
>> applications and got away with it.  No more.  As long as we're in True
>> Confessions mode, I've used braid from old coax (outdoors, even!) and
>> soft-soldered strap and braid to ground rods.  No more of that, either.
>> Live and learn, especially now that I live back in the lightning zone
>> (Missouri) with towers on a high spot.
>>
>> So the advice is just to use the right stuff for the job.  It's not that
>> expensive (a lot less than your insurance deductible, that's for 
>> sure) and
>> has been engineered to minimize corrosion and handle the mechanical
>> requirements of the application.
>>
>> I also got a question about CadWeld and those are great for ground
>> electrodes but I would never use them on the tower itself.  It may be
>> possible to safely weld a connection to a tower but I wouldn't do it 
>> to a
>> tubular load-bearing leg, not to mention the dissimilar metals 
>> involved and
>> all that. I wouldn't want to weaken a cross-brace either, especially 
>> when
>> there are other options designed for that exact application. Maybe 
>> someone
>> with broadcast tower experience could weigh in on that.  I repeat, 
>> for us
>> hams, just buy the right stuff and and do what the manufacturer says.
>>
>> 73, Ward N0AX
>> _______________________________________________
>>
>>
>>
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