It is common here, where when the fine particled (clay/silt) soils=20
freeze and expand sometimes lifting the surface an inch or 2, to provide=20
a loop below ground in cables and tubing to allow for the movement.=20
Concrete drives and walks next to buildings with deep (below frost line)=20
foundations need a bond breaker to allow movement of the concrete=20
vertically. If not done, the concrete drive/walk has been known to lift=20
the building if there is not sufficient weight.

On 3/4/2011 11:54 AM, RussellMc wrote:
>>   or even reduce peak voltage
>> static discharge if  storm (nothing helps a direct strike, that removes
>> the Chimney usually!).
>>     =20
> If cable is run into the ground - twisted pair or coax etc, then
> providing a loop or few at ground level will often result in a
> Lightning strike causing burn-through to ground at a point on the
> loop(s).
>
> This does not make sense analytically as the loop inductance is too
> small to explain this effect. But, it is reported to work. Stopping
> lightning before it gets into 'real stuff' is a good idea [tm].
>
>
>       Russell
>
>   =20
--=20
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