Date:         Tue, 19 Jun 2007 22:46:55 -0700
Reply-To:     Jack <john.cook58@VERIZON.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Jack <john.cook58@VERIZON.NET>
Subject:      Re: Grounds (was Quality Inverters)
In-Reply-To:  <90A648EF-AF86-493F-A238-A08A5E9D543F@knology.net>
Content-type: text/plain; charset=US-ASCII

Not directly related to inverters but perhaps of some interest.

A pet peeve of mine regards the word, "Ground".  As used in electricity and
electronics, the word is an unfortunate historical artifact which, in my humble
opinion, should be removed from use, since it's too often misunderstood.  It
implies some magic iso-potential conductor connected to earth which rarely
exists outside of a text book.  Given common conditions such as high fault
currents, fast rise/fall surges (e.g., sparks), that "ground" is anything but
iso-potential. This misunderstanding can lead to serious problems, even from
designers who should know better.  (This isn't even beginning to deal with high
speed digital circuitry, analog instrumentation, A/D, D/A and RF systems.)

Much better to use the words, frame, shell, chassis, shield, common, 3rd wire,
green wire, etc.  Those more descriptive terms provide better understandings of
what the conductor is and (sometimes) what its purpose is.  In large system
schematics, we might see the identifiers, frame-1, frame-2, frame-3, shield-1,
etc., even though the connections may be tied together somewhere.

Sorry to rant.  And sorry if the above makes little sense to you.  You have to
have been there.

//Jack