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From: larry@kitty.UUCP
Newsgroups: sci.electronics
Subject: Re: Neutral-Ground Shorts
Message-ID: <1795@kitty.UUCP>
Date: Wed, 10-Jun-87 22:56:58 EDT
Article-I.D.: kitty.1795
Posted: Wed Jun 10 22:56:58 1987
Date-Received: Sat, 13-Jun-87 07:31:03 EDT
References: <820@sdcc12.ucsd.EDU> <583@inuxh.UUCP> <1989@cbmvax.cbmvax.cbm.UUCP>
Organization: Recognition Research Corp., Clarence, NY
Lines: 32
Summary: Only ONE neutral-ground bond at service entrance panel

In article <1989@cbmvax.cbmvax.cbm.UUCP>, grr@cbmvax.cbm.UUCP (George Robbins) writes:
> > Neutral and ground should be tied together.  Look out for the outlets
> > in which it isn't.  
> 
> Neutral and ground should be tied together *** at or near the fusebox ***.
> Having them tied together at the outlet is wrong and a good indiction that
> you should look for more questionable and dangerous wiring practices.

	The National Electrical Code (section 250-23) makes it clear that
the current-carrying neutral and the earth ground wires should be bonded
at one and ONLY ONE place in any electrical system: the service entrance
panel (i.e., main disconnect) immediately following the meter.

	There are several reasons for this:

1.	An open or high-impedance (i.e., faulty) neutral line in the building
	distribution wiring, coupled with a high-impedance (i.e., faulty)
	equipment ground (like poor conduit bond) could result in dangerous
	voltages present on the earth grounds of interior wiring.

2.	Ground loops can exist in that some of the equipment (i.e., earth)
	ground wiring will be carrying current under normal conditions,
	thereby resulting in equipment grounds being at other than zero
	potential.

3.	The result of (2) above can cause significance interference with
	data communications equipment.

<>  Larry Lippman @ Recognition Research Corp., Clarence, New York
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