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Lightning Arrestor

11/06/2009 12:41 AM

It it safer to install lightning arrestor (rod) for a small life guard type of watch tower.

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#1

Re: Lightning Arrestor

11/06/2009 3:03 AM

It's safer than not installing one...

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#2

Re: Lightning Arrestor

11/06/2009 7:57 AM

Based on the veritable plethora of information you provide, I'd say, not during a thunder storm.

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Guru
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#3

Re: Lightning Arrestor

11/06/2009 1:46 PM

Safer for the TOWER for sure. Rod and conductor will help minimized strike damage to structure. However, I'd strongly advise anyone in the tower to LEAVE the area when a thunderstorm approaches. Seriously, NO ONE should be swimming at that time either!

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#4

Re: Lightning Arrestor

11/07/2009 12:48 AM

I would say no, you do not want to attract the electrical charge and if you did a attract a discharge how would you dissipate the energy. The energy flows from the point of contact and dissipates in a circle similar to E=I x R x 1/r^2. I=current 1 x 10^5 amps and R = resistance of the soil 1 x 10^6, therefore E~=1 x 10^11 volts. Sand R being quite high (glass) the resulting voltage would be extremely high for a great distance around the rod, probably more deadly than with just a simple wooden structure. The wooden structure if dry and painted would not attract a discharge thus you and others would be safer. Better yet "Run Forest run"!

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#7
In reply to #4

Re: Lightning Arrestor

11/08/2009 8:03 PM

Thank you for your response. But it is a steel structure. I agree with you if it is a wooden structure.

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#5

Re: Lightning Arrestor

11/07/2009 11:33 PM

Lightning arrestor basically installed in structural elements such as hangars, high rise structural buildings, ammunition bunkers and similar structures. Lightning will strike the current conductive object which is highest above the ground at millions of volts and dissipated in milisecond leaving part of your building wrecked or even set it on fire. Lighting arrestor attracts lightning strikes because it is installed above roof and a highest object within the area. Safer to your guard shack tower but be sure to insulate your down conductor with high grade PVC pipes from lightning rod base to the grounding electrode pit, to avoid contact in any of the structural elements. If you have large building roof area the maximum air terminal/rod spacing is 25ft (7.62m) at 60cm lightning rod length. Increase rod length 2in(5.08cm say 5cm) for every 1ft(30cm) increase in spacing between the lightning rods.

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#8
In reply to #5

Re: Lightning Arrestor

11/08/2009 8:05 PM

Thank you for your good comments and info.

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#6

Re: Lightning Arrestor

11/08/2009 12:03 AM

Tallest structure in a lightning prone area with or without protection WILL eventually get a strike. With points and ground wire, most of the energy will go to ground. Without protection, the arc will corkscrew through structure instantly flashing ANY microscopic traces of water to steam. Metal structure should be fine, but wood can be blown into splinters and cinder block into chunky rubble. Direct strike to wood structure may also cause a fire. The damage from even a small strike can be significant.

Contrary to popular myth, a few small spikes and ground wire protecting a typical house structure do NOT initiate lightning strikes. The field disturbance is far too small and localized. However, a lightning strike that does occur near the structure will tend to follow the path of least resistance through the spikes and wire to ground. This is EXACTLY what is intended to protect the structure.

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