Grounding a Weathervane

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  #1  
Old 08-05-02, 10:32 AM
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westportwarrior
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Grounding a Weathervane

I plan to install a metallic (brass?) weathervane on my 2-story house. There were no instructions regarding the proper grounding. I need to know: (1) what type of cable should I use? (2) should the cable only run outside the house (common sense I suppose) and (3) how should both ends the weathervane end and the "ground-end" be connected? Any other pointers would be appreciated.
 
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  #2  
Old 08-05-02, 02:14 PM
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Wgoodrich
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Look at your manufacturer's installation instructions, see if those instructions tell you to ground this weather vane. If so follow those manufacturer's instructions. If you manufacturer's installation instructions say nothing about grounding that weathervane then you do not have to install a grounding conductor to that weathervane.

If you are installing this weathervane as a lightening protection product the again follow the manufacturer's installation instructions.

Teh NEC has no rules concerning weathervanes or lightening protection systems.

Hope this helps

Wg
 
  #3  
Old 08-06-02, 06:06 AM
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westportwarrior
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Thanks again WG. I hope you received my other "thank you" too. This is an antique weathervane off some old farm house in up-state NY and it comes with no instructions. I would have followed the old adage RTFM (read the manual), but there is none! I am using this mainly for decoration. But in a thunderstorm the other night I got a little nervous because my bed is directly under the weathervane. Could be a problem.
 
  #4  
Old 08-06-02, 11:19 AM
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Wgoodrich
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Many premanufactured church steeples come with an 8 awg copper wire connected to the steeple. The manufacturer's instructions suggest connecting that 8 awg conductor to a 8 awg conductor that is ran directly to the grounding bar of the main servire rated panel. Through the structures attic and down the wall into the panel with sweeping curves in teh wire and no sharp turns. This is in thoughts of lightening strikes being invited to hit that church steeple.

That is as close to our situation that I can get. There is no requirements that I know of in the NEC that requirest that weahtervane to be grounded.

Hope this helps

Wg
 
  #5  
Old 08-06-02, 05:08 PM
S
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Why would you want to invite a strike into the panel,,, wouldnt to a seperate ground rod make more sense,,, or no ground at all.
 
  #6  
Old 08-06-02, 06:38 PM
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Wgoodrich
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sberry, the design of a metal weather vane is generally believed to be an invite of a lightening strike. Installing an equipment grounding conductor to the grounding electrode system would be the normal thing to do to try to address that concern.

The NEC requires that all grounding electrodes be connected together to make a grounding electrode system serving a structure. It is not a good idea to just add a ground rod here and there throughout a building. Even when the NEC allows a separate ground rod to be installed due to a manufacturer's concern that sensitive equipment will fail if without that separate ground rod you still are required to connect that rod by way of an equipment grounding conductor to the grounding electrode system through the panel. Same place we talked of placing the weather vane to the grounding system.

Hope this helps

Wg
 
  #7  
Old 08-06-02, 07:41 PM
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I think I opt for a plastic weather vane then.
 
  #8  
Old 08-07-02, 12:03 PM
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Wgoodrich
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sberry27, I think your suggestion of a plastic weathervane is the best idea on this posted thread. I could not agree with you more!

VERY GOOD THINKING !

Wg
 
  #9  
Old 08-08-02, 05:11 AM
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This might be a good time to explain the real purpose of a lightning rod. Contrary to popular belief, a lightning rod does not attract lightning. Quite the opposite, its purpose is to "bleed" off the difference of potential between the surrounding atmosphere and the ground to which is is bonded - thereby, if lucky, it will prevent the build up required to create the arc (lightning).

The reason for the sharp point is that the potential that can build on an electrode is inversley proportional to the surface area of a sphere. Another example of this is an automobile antenna. Ever noticed the ball on top? That does the opposite of the lightning rod, in that is forces a small build up which "pops" off periodically, unnoticed by the radio listener. Without it, the potential could not build up and would bleed almost continuously, created static in the radio.

As for the weather vane, that's a difficult question. Without the addition of a rod, I would suggest you leave it alone as far as grounding, unless someone else posts a good reason for it.

Good luck,
 
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