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RE: Lightning and neutral grounding



I don't know if I can shed any additional information on this subject.
I apologize if this same information has been shared already...I have
not read through all previous posts (bad practice, I know but I've been
out all week and am just now mail wading).

The Neutral conductor is designed as a "current carrying conductor".
The Ground is a "non current carrying conductor".  In other words, if
amperage is ever passed via the Ground conductor, something is
wrong....very wrong.  GFI breakers are designed to trip under such
circumstances, hopefully before the over-current protection (@20 amps,
for example) kicks in.  Considering that it only takes about 40 mA to
kill an average human....by the time the current gets all the way up to
20A, it may be too late.

According to code, the Neutral, or grounding conductor, MUST be the same
wire size as the other phase or hot wires.  The Ground, or grounded
conductor, can under certain circumstances be a smaller size conductor
than the other wires.

The Neutral and Ground conductors are connected together at the power
panel and any previous power source (such as at the secondary of a line
transformer) for the purpose of providing a ground reference to all line
voltages and for safety sake (which speaks to the need for a low
impedance connection between mother Earth and the ground rod
itself....which is another story by itself).

Gary

-----Original Message-----
From: owner-AMSAT-BB@AMSAT.Org [mailto:owner-AMSAT-BB@AMSAT.Org] On
Behalf Of kb9cry@attbi.com
Sent: Tuesday, March 11, 2003 4:12 PM
To: Jon Ogden
Cc: Roy Welch; Greg D.; amsat-bb@AMSAT.Org
Subject: Re: [amsat-bb] Lightning and neutral grounding

If the neutral in AC wiring is eventually connected to ground at the
service
entrance, why have a third line that is grounded anyhow.  Why not just
ground through neutral?

Theoretically this it true but I've asked every electrician I've ever
known and they all are brain-washed into saying, "But that's not in
accordance with NEC."  And I now believe it too.  Because the code says
so.  Period. And, once again, in three phase power applications, you can
come up with many examples where a load will become inbalanced  or a
back feeding situation develops and the neutral will end up carrying
some current.  So the fourth ground wire is required to protect the
operator from electrical shock and/or to provide a ground path back to
the breaker so it can operate correctly.  In a nut shell, no, don't do
it.


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