WARNING! WARNING! WARNING! (was [Elecraft] ESD recommendation)

[David Woolley]

Ron D'Eau Claire wrote:
> That's why a connection to earth ground is recommended and important. It's
> often pointed out that it doesn't matter if everything is grounded as long
> as it's at the same potential. That's true, but connections to the earth are
> usually all around us, often in unexpected places. 

Modern electrical installations, at least in the UK, and I think also in 
the US, often use a system called Protective Multiple Earthing.  With 
this all exposed metal work in a building should be connected together 
and to the mains ground wire, but will not be connected to the actual 
earth at the property boundary (it will be connected to mains neutral). 
  If you have this sort of installation, you must not connect anything 
to true earth unless you are prepared to assume that you are connecting 
it to mains live, as, in some fault conditions, the difference between 
the true earth and mains earth voltage can be the full supply voltage.

(Such installations also require special consideration with respect to 
antennas and functional (RF) earths.)


-- 
David Woolley
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