On Tuesday, November 26, 2013 11:13:49 AM UTC-5, bud-- wrote:
On 11/25/2013 1:43 PM, nestork wrote:
bud--;3155057 Wrote:
The earth does not complete the circuit. Wires complete the circuit.
Bud, until recently I would have agreed with you. But, whomever wrote
this web page obviously knows something about electric power generation
and distribution and seems to disagree:
http://tinyurl.com/y4syno6
Look at the bottom paragraph in the section entitled "The Power Plant:
Three Phase Power" where it says:
And what about this "ground," as mentioned above? The power company
essentially uses the earth as one of the wires in the power system. The
earth is a pretty good conductor and it is huge, so it makes a good
return path for electrons. (Car manufacturers do something similar; they
use the metal body of the car as one of the wires in the car's
electrical system and attach the negative pole of the battery to the
car's body.) "Ground" in the power distribution grid is literally "the
ground" that's all around you when you are walking outside. It is the
dirt, rocks, groundwater, etc., of the earth.
I don't think he could have said it any clearer.
As trader noted, the author says "there are four wires coming out of
every power plant: the three phases plus a neutral or ground common to
all three."
The 4th wire is a neutral, which is grounded.
The author has a problem of identifying neutrals as grounds throughout
the piece.
Nowhere does the author describe how earth is used as a conductor in
power transmission.
------------------------
"The fourth wire lower on the poles is the ground wire"
The 4th wire is a neutral which is earthed.
--------------------------
"Past a typical house runs a set of poles with one phase of power (at
7,200 volts) and a ground wire (although sometimes there will be two or
three phases on the pole, depending on where the house is located in the
distribution grid)."
The "ground wire" is in fact a neutral wire (which is earthed).
--------------------------
"There are two things to notice in this pictu
There is a bare wire running down the pole.
This is a grounding wire. Every utility pole on the planet has one."
Actually every utility pole does not have one. With the overhead
distribution in Minneapolis poles with transformers have an earthing
wire. Other poles may or may not have one.
---------------------
Continuing "If you examine a pole carefully, you will see that the
ground wire running between poles (and often the guy wires) are attached
to this direct connection to ground."
The wire is a neutral that is earthed.
The distribution voltage in my area has one of the 3-phase wires tapped
off the distribution and feeding 4-8 blocks. The 3-phase neutral is
tapped off the supply neutral at the same place and runs with the phase
wire. As above, the neutral is earthed at multiple locations. The same
primary neutral is used as the secondary neutral, and so the secondary
neutral at the transformer is earthed.
-------------------------------
Continuing
"There are two wires running out of the transformer and three wires
running to the house.
The two from the transformer are insulated, and the third one is
bare. The bare wire is the ground wire."
As about everyone here knows, the 3rd wire is a neutral, not a ground.
-------------------------------
There is an electrical diagram of a transformer with the secondary
center tap labeled "ground".
Also is obviously a neutral.
--------------------------------
There are multiple pictures of distribution lines, all of which have a
neutral. Sometimes the author misidentifies the neutral as "ground".
Transmission lines also have a neutral. Sometimes it is run on the top
for lightning strikes.
----------------------------
"When a 120-volt power line connects directly to ground, its goal in
life is to pump as much electricity as possible through the connection."
The electricity does not flow to earth. It returns to the utility
transformer through the N-G bond at the service and through the service
neutral wire.
-------------------------------
The author consistently misidentifies neutral wires as "ground" wires.
His pictures show neutrals along with distribution wires. He does not
explain how the earth is used in power distribution. He does not appear
to understand power distribution.
This piece is fatally flawed.
My hat's off to you Bud. Excellent job taking it apart piece by
piece. What's ironic is Danny came in here not knowing the difference
between a neutral and ground with a house service. Now he's hitched
his wagon to an author that clearly doesn't know the difference between a
neutral and a ground either.