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From: les@celerity.UUCP (Les Merrill)
Newsgroups: sci.electronics
Subject: Re: Neutral-Ground Shorts
Message-ID: <221@celerity.UUCP>
Date: Tue, 23-Jun-87 14:50:55 EDT
Article-I.D.: celerity.221
Posted: Tue Jun 23 14:50:55 1987
Date-Received: Thu, 25-Jun-87 02:53:02 EDT
References: <820@sdcc12.ucsd.EDU> <583@inuxh.UUCP> <467@rlvd.UUCP> <258@uvicctr.UUCP>
Reply-To: les@celerity.UUCP (Les Merrill)
Organization: Celerity Computing, San Diego, Ca.
Lines: 21

>What I have wanted to know for years is,  why is residential service
>referred to ground at all?  I understand why they balance and ground 
>high-voltage transmission lines.  It seems to me that, if the transformer
>was used to isolate the residential service from ground everyone would
>be a lot safer.  How about it?

Safety is best when the transformer is center-tapped and grounded
at the utility pole.  A totally ungrounded circuit is subject to accidental
connection to dangerous voltages with no warnings available. Center-
tapping is the way they do it, except that the basic supply voltage is
220 v. balanced to ground/neutral. You plug into one half of the supply
when you use the common residential outlet.

The notion of one-side-is-ground hails back to the beginnings
of everything. There was a Samuel F. B. Morse who had something
to do with a single-ended telegraph circuit between Washington and Baltimore
(or was it Piladelphia ?) where the earth really WAS the other side of the
circuit..

--les
bigbang!celerity!les