Posted by
David Woolley (E.L) on
Nov 25, 2007; 11:16am
URL: http://elecraft.85.s1.nabble.com/WARNING-WARNING-WARNING-was-ESD-recommendation-tp366973p366976.html
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
Emails are not formal business letters, whatever businesses may want.
RFC1855 says there should be an address here, but, in a world of spam,
that is no longer good advice, as archive address hiding may not work.
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