Are tyou asking if they just drove a ground rod for the grounded conductor? If so it would never work.In the earley days of power did the power co ever use earth for the grounded conductor ?
Nonetheless, it has been done. It's called SWER, which stands for Single Wire, Earth Return.
You'd only see it for primary distribution, and only for single phases, and mostly rural areas.
It seems that, the higher the voltage, the better the earth is at being an effective conductor.
In the earley days of power did the power co ever use earth for the grounded conductor ?
Are tyou asking if they just drove a ground rod for the grounded conductor? If so it would never work.
Nonetheless, it has been done. It's called SWER, which stands for Single Wire, Earth Return.
You'd only see it for primary distribution, and only for single phases, and mostly rural areas.
It seems that, the higher the voltage, the better the earth is at being an effective conductor.
Right on, if you tried to use earth as a conductor even between ground rods only a few feet apart the resistance is likely too high for any reliable operation of any system of 600 volts or less.
A few years ago when we had big ice storm take down many miles of lines and poles, they did not always put the (primary) neutral back up right away because the system would operate without it, the earth was their neutral. This allowed them to get customers back on a little quicker and come back and put the neutrals up sometime later.
ARTICLE 100 Page 70-27 Grounded Conductor. A system or circuit conductor that is intentionally grounded.
Does that not mean Grounded to Earth??
ARTICLE 100 Page 70-27 Grounded Conductor. A system or circuit conductor that is intentionally grounded.
Does that not mean Grounded to Earth??
ARTICLE 100 PAGE 70-27 Ground . The Earth
The general mass of earth, as distinct from an earthed or grounded conductor, was never AFAIK, used as a current carrying conductor at utilisation voltages.
The resistance would be too great leading to excessive power loss and variation of voltage.
"Ingenious" persons did sometimes use an earth/ground return when supplying a single distant lamp, for example at the end of a long driveway.
For high voltage, low current, long distance circuits, an earth return can be used and sometimes is.
Over a long distance the resistance of an earth return is often less than a copper wire.
It is generally accepted that the general mass of earth has effectively zero resistance. The problem occurs when trying to make a connection to the earth, any feasible design of earth/ground rod has a very limited surface area, and therefore results in a high resistance connection.
Put another way, suppose that you drive 2 typical ground rods 100 yards apart, and measure the resistance between them. Typical result might be 25 ohms.
Now drive a similar pair of ground rods 100 miles apart and again measure the resistance between them, it will be the same at say 25 ohms.
No one would use the rods 100 yards apart as part of a power circuit, 25 ohms would result in a very considerable loss, 100 yards of thin copper wire would have a much lower resistance and be very cheap.
If however power had to be transmitted over 100 miles at high voltage, then use of a single conductor with an earth return is worthwhile.
100 miles of neutral or return conductor would likely have a resistance greater than 25 ohms, therefore the earth return is actually more efficient than a second copper wire, and very much cheaper.
In practice a more elaborate structure than a single residential type earth rod would be used, and the resistance might be 10 ohms or less.
An earth/ground return was the norm in early telephone and telegraph systems, and is still sometimes used.
Over a dozen miles or more, the earth return was cheaper and of lower resistance than a second copper wire.
Wow this is some very cool info. Do you have a source or reference I can look for? I'd like to bring this topic up as a discussion with my apprentices in class as a "food for thought" kind of thing.
Isn't there an issue with cows and other livestock with SWER? I remember reading about that somewhere
Just to mention it, this is also what paralyzes swimmers in electrified water.Cows are vulnerable to earth currents, they dont wear shoes and theire feet are some distance apart, in contact with the often wet or muddy ground.
Therefore any significant voltage gradient in the ground would result in the hind and fore feet of the cow being at different voltages.
Just to mention it, this is also what paralyzes swimmers in electrified water.
And what made Tesla's magic lighting system work, the one where he lit bulbs shoved in the ground in the middle of a field with no wires at all.