[Alberg30] Faraday's cage lightning protection

[George Dinwiddie]

A Faraday cage does not depend on grounding.  There's a simple description
at http://www.physics.gla.ac.uk/~kskeldon/PubSci/exhibits/E3/  The short
answer is that any space enclosed by conductors is protected from static 
charges outside that space.

On a sailboat, this tends to protect the inhabitants, but not necessarily
the boat, itself.

 - George

P.S. There's a really excellent biography of Michael Faraday by L. Pearce
Williams that discusses his work as well as his life.  It's out of print,
but if you enter "L. Pearce Williams" for author and "Faraday" for title
in the ABE search box on http://www.alberg30.org you'll find it available
at a reasonable price.

> J Bergquist said:
> 
> Dear List,
> 
> I've asked about this before, and George gave me a very good answer, 
> which was that the best way to avoid being struck by lightning is to 
> lead an upstanding life.
> 
> What I want to know is does the Alberg 30 mast/rigging form Faraday's cage?
> 
> The answer to this question, I think, lies in answering the question of 
> whether or not the conductor must be grounded in order for Faraday's 
> cage to be well-formed. Since the mast is deck-stepped, and the keel is 
> encapsulated, the A30 does not appear grounded as delivered from the 
> factory. However, it would be possible to install an aftermarket ground, 
> I would think (though this would doubtless have implications for bonding 
> and galvanic corrosion, issues I'd just as soon not think about if I 
> don't have to).
> 
> So I'm wondering if the A30 as rigged (ie. ungrounded) provides a 
> Faraday's cage type protection from electromagnetic discharge, or is it 
> necessary for the conductor(s) to be grounded in order for Faraday's 
> cage to be well-formed.
> 
> Having spent a few nights this summer out during thunderstorms, I'd 
> personally like to know whether or not I should worry about installing a 
> ground this winter.
> 
> Anybody know about this?
> 
> J Bergquist
> #287 Calliope
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-- 
 ----------------------------------------------------------------------
  When I remember bygone days                         George Dinwiddie
  I think how evening follows morn;            gdinwiddie at alberg30.org
  So many I loved were not yet dead,           http://www.Alberg30.org
  So many I love were not yet born.
                                            'The Middle' by Ogden Nash
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