[Antennas] Ground rod questions (Ground currents)

Wed Jul 1 00:15:52 EDT 2009

I disagree in part...but agree with most of your post, Bob..
The Neutral or "Static" IS carried back to the substation and all the way
back to the generation station..it is PART of a single or three phase
circuit and the static ground off the 3 phase is bounded to the neutral of
the center tapped xfmr on the pole...ALL of it is tied together for
reference of the 1 phase 120V/220V....when you have 110 on one side and less
than 110 on the other (like 7V?) but showing 220 across the two hot wires
from the xfmr, you have an OPEN Neutral that can KILL and cause fires....I
had to argue with a contract crew for three hours after Umberto came through
SETX and did damage at a friend's house...funny, the company crew leader,
when he showed up, said "OH HELL, it's Boone...HE KNOWS what's wrong and YOU
guys (meaning the contract crew) have been arguing with HIM???" The crew
leader knew me for 20 yrs in the company...and I pulled my hard hat out to
make the point...took the idiot contract crew 3 hours what a single COMPANY
man would have fixed in 30 minutes!!! :)
YES, the SAFETY ground in equipment is for short circuit protection....you
can still get shocked if the neutral from the xfmr to the house opens and
the ground is still there...had that happen not too long ago (see above)...
Chris
WB5ITT
Gulf States Utilities (Now onwed by Entergy) w/Riverbend Nuclear Plant, last
1 built in the US in the 80s...so far ;) 1984-1996
Chief Engineer, KDMX/KEGL FMs and 1190AM Dallas-Fort Worth (and we used a
lot of 3 phase and single phase!)
Now with CenterPoint Energy (former Houston Lighting and Power),
2004-present
-----Original Message-----
From: antennas-bounces at mailman.qth.net
[mailto:antennas-bounces at mailman.qth.net] On Behalf Of rbethman
Sent: Tuesday, June 30, 2009 2:12 PM
To: Antennas
Cc: C. Whitaker
Subject: Re: [Antennas] Ground rod questions (Ground currents)
The three phase "Y" does NOT derive neutral from the central 
connection! That central connection IS ground.
I do NOT know where you have been involved in power generation and/or 
distribution. I sure hope you are NOT so now. The center of the "Y" 
has ALWAYS been the ground beginning at the generator. This is the way 
it IS.
Neutral wires are derived from center tapping single phases on a 
stepdown transformer otherwise known as a distribution transformer, 
located either on a power pole OR a pad mounted one in an underground 
system.
Neutrals are NOT carried as the main power distribution system going 
back to substations or generators.
ALL "Y" systems reference their phase voltage to ground, which IS the 
center of the "Y". The ground is for safety in a short circuit, NOT to 
be a safety in the event the neutral should open! That is PATENTLY false!
Suggest you consult the NEC and other applicable documents. Also 
include electrical engineering books.
I may be retired military, BUT - I am ALSO a Board certified Nuclear 
Power Plant Operator and Technician.
Bob - N0DGN
C. Whitaker wrote:
> de WB2CPN
> Perhaps we need to clarify and identify the 
> relationship between the "Neutral" wire which
> comes from the center of the 3-phase "Y" or
> the center of the single-phase transformer which 
> feeds most if not all houses and other small users, 
> and the "Ground" wire that connects to that Neutral
> wire either at the pole or at the service entrance.
> The neutral wire is to carry the current that results
> from uneven currents in the 2 hot wires, while the
> "Ground" wire is to prevent someone from being
> hurt if the neutral wire open up somewhere and 
> makes what's left of it in the house hot. Nothing 
> has any interest in noise, radio or otherwise.
> Look at this: A housetrailer neutral and ground
> wires were bonded inside the trailer. Only the
> neutral wire came to the meter, and then to the
> pole. When that neutral wire opened, (bad splice),
> everything on one side of the 220/110 feed was
> placed in series with everyting on the other side
> of the feed. The refer on one side, when it came
> on, blew heck out of the clock motor which was
> on the other side. Then, the refer had no power.
> TRIVIA
> Clete in South Central PA
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-- 
Bob - NØDGN
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