[TowerTalk] Cadweld vs clamps

[Jim Lux]

On 10/23/14, 11:34 AM, Bill Turner wrote:
> ------------ ORIGINAL MESSAGE ------------(may be snipped)
>
> On Thu, 23 Oct 2014 06:49:13 -0500, Keith Dutson wrote:
>
>> My experience shows the difference is time.  No clamp can be expected to
>> maintain its contact area with the wire and rod in soil over a long period
>> of time due to chemical reaction between the soil, wire, clamp and rod.
>> Cadweld solves this problem by isolating the chemical action to external
>> parts of the connection.
>
> REPLY:
>
> First, I wouldn't worry about a few microns of corrosion, especially
> when lightning is concerned. A lightning bolt has already traveled
> thousands of feet through an insulator (air) - another thousandth of
> an inch of corrosion is nothing.
>

I would worry about Intermodulation from a corroded connection.  From a 
lightning protection standpoint, you could have a layer of tape in 
between: it will punch right through.  Static charge or induced voltages 
would be a problem.

And, many hams use their electrical safety ground as a double/triple 
duty vertical antenna ground/lightning ground.  Whether that is a wise 
idea I leave for another discussion.  I tend to think that one should 
keep the functions separated, and might even advocate for RF choking in 
the required bonding jumpers between grounding systems (although I 
believe someone pointed out that a suitable choke might be impractical)


> Second, as someone pointed out, the clamp itself should not be buried,
> for two reasons. One to reduce corrosion and two, to permit
> inspection.
>

I think it's the latter that drives the code requirements.