Bob--
I don't know how the call got messed up-- it's a pre-done Sig (?) I am
W4BSG.
Of course I will accept that lightning can explode concrete, under the
proper conditions. That goes along with the premise that it is
impossible to prove a negative.
My experience includes working for 38 years in what is classed as an
explosives plant, with real UFER grounds on every building in a 1000
acre plant. The only lightning damage we had was to trees (away from
buildings) and to a chem lab that had had some Copper cables cut by
painters.
On a proper Ufer ground, there is never a point where rebar crosses a
soil-to-concrete interface. Such a situation will often cause cracks in
concrete, without any lightning; it's a matter of the expansion of rust
on steel. Copper penetration is OK.
Enough, we will neither convince the other.
Bill--W4BSG
On 4/17/2011 10:50 PM, Robert Harmon wrote:
>
>
> Bill,
>
> I knew there was a risk of my post evolving into a long, long thread. :-)
> I provided historical data from past projects I have managed which
> involved lightning strikes
> and documented in our engineering files.
> I sense that evidence of actual documented information about this
> "urban myth"
> is unsettling to you. To relieve me of spending the time pulling the
> engineering files and
> then to relieve you of the need to defend your belief (and on and on)
> let's see if we can find closure.
>
> Would you accept the fact that a lightning strike can crack/explode
> concrete under the right
> circumstances ?
>
> Bob
> K6UJ
>
> what is your call Bill ? It shows as W4BDSG at the end of your message.
>
>
>
> On Apr 17, 2011, at 6:54 PM, Bill Aycock wrote:
>
>> Bob--
>> Despite what you said, it IS still an Urban myth. Your own statement
>> includes information claiming that this was NOT a proper Ufer system,
>> and you provided no descriptions of the circumstances.
>> Bill--W4BDSG
>>
>> On 4/17/2011 3:55 PM, Robert Harmon wrote:
>>> Dave,
>>>
>>> Wow, did I hit a nerve ? Didn't mean to stir up deep rooted
>>> feelings on this subject.
>>>
>>> Lets take one thing at a time. Our local building code does not specify
>>> connecting the tower to the rebar cage. It is also not required in
>>> the national
>>> Uniform Building Code or the NEC.
>>>
>>> In building department inspections I have seen three separate
>>> instances of cracked concrete tower footings caused by lightning
>>> strikes. Two common denominators in each of these was the lack of
>>> tower grounding to a ground rod(s),
>>> and a required building permit was not attained (which would have
>>> prevented this)
>>>
>>> Urban myth ? hihi
>>>
>>>
>>>
>>> Bob
>>> K6UJ
>>>
>>>
>
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