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Re: [RFI] CHECK your grounds.

To: rfi@contesting.com
Subject: Re: [RFI] CHECK your grounds.
From: Jim Brown <jim@audiosystemsgroup.com>
Reply-to: jim@audiosystemsgroup.com
Date: Wed, 26 Jan 2011 14:49:46 -0800
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
On 1/26/2011 12:29 PM, KD7JYK DM09 wrote:
> I have taken photos of our electrical "grounds".

You need to study the fundamental principles of AC power distribution. A 
GROUND conductor does NOT carry load current -- it's sole function is 
SAFETY.  The current carrying conductors are the Phase and Neutral 
conductors. A 240V single phase system has two Phase conductors and a 
Neutral conductor, fed from a center tapped  transformer. The two Phase 
conductors are connected to the two ends of the transformer, and the 
neutral is connected to the center tap. There is NO ground conductor 
between the power company and your home. Rather, the Neutral conductor 
is grounded FOR LIGHTNING SAFETY both at the transformer and at the 
point where it enters the building.  A separate Equipment Ground 
conductor (the Green wire) is carried with the phase and neutral 
conductors to every outlet, and to every piece of equipment wired 
directly into the power system. The purpose of that Green wire is 
SAFETY. It's function is to cause a fuse (or breaker) to blow if 
something goes wrong.

The EARTH is a lousy conductor, and should NEVER carry current in a 
power system.  A connection to earth is almost never part of a solution 
to an RF or noise problem.

There is a tutorial discussion of power systems on my website.


73, Jim Brown K9YC
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