Someone please explain to me

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beachbumjeremy

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I am an apprentice starting my fourth year of education. All my life and all during school, I have been taught that all voltage wants to do is go to ground, whether through a neutral or a ground, that's it's home. My teacher today told my basically that this isn't so, that all the voltage (energy) wants to do is get back to the center tap on the winding off your pole. He explained that when anything goes to ground, lets say a faulty hot in an appliance goes to ground, it travels down your ground rod, through your ground, up the ground rod of the power pole, and back into that center tap winding.
I asked him" So lets say I took a 500 mcm and ran lets say 2000 ft into the middle of nothing, hooked one side up to 120 volt bussing, and grabbed the other side 2000 ft away and stood in a puddle of water bare foot, I would not be shocked because there is too much resistance in the 2000ft of dirt for me to feel anything?" and he responded that I was correct.
Is this all accurate? It's so different from what I've been taught my whole life that it's driving me nuts thinking about it.
 
Current will seek all parallel paths back to the source. The source in your case is the secondary side of a transformer. The earth is a path also, but not the best. The earth is a path because the transformer at the pole or pad is grounded to the earth. A bond is made between the secondary transformer neutral or a phase conductor that is attached to a ground rod. Remember it takes two wires to complete a circuit. The bonding to earth at the source make earth now path for current to flow back the the source.

In the case of you standing you standing in the water with the 500kcmil, the earth is very resistive. At 120V a very small current would flow, try the same this with 13.2Kv things will smoke in a hurry.
 
As 72.5 said, current seeks and has to return to it's source, the only reason earth would come into play would be as a conductor, and in an ungrounded system it would not even perform as a conductor.

Roger
 
jermey,
All my life and all during school, I have been taught that all voltage wants to do is go to ground, whether through a neutral or a ground, that's it's home.
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Many people have been taught and believe that statement. It is one of the biggest reasons that people do not understand grounding and bonding.
I asked him" So lets say I took a 500 mcm and ran lets say 2000 ft into the middle of nothing, hooked one side up to 120 volt bussing, and grabbed the other side 2000 ft away and stood in a puddle of water bare foot, I would not be shocked because there is too much resistance in the 2000ft of dirt for me to feel anything?" and he responded that I was correct.
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You will be shocked. There will not be enough current flow on the circuit to cause a voltage drop on the wire, so you will have 120 volts between the end of the wire and the earth, even with the current flowing through your body. The current through you will be based on the resistance of your body and the earth. It will be enough to kill you.
Don
 
Jeremy
The example you give will have distinct results in voltage and current flow.
The best idea is not to toucht the current path, but to use a meter to measure the results, this way we can continue to have your presence on this site :wink:

It is funny how so many of us have to relearn some of what we were taught as apprentices...you would think by now that this issue would be a thing of the past. It is good you have learned as an apprentice. Good luck and stay in this industry, we need more good electricians.
 
Current flows back to it's source, not back to ground. . The ground can be part of the path that it flows but it's not the ground itself that the current is seeking.

Kind of sounds like Eastern philosophy, doesn't it ? . But it's very true Grasshopper !

David
 
A good way to dismiss the "earth is home" thinking is to demonstrate with a 1:1 isolation transformer.

The output is neither hot nor neutral, unless you define one as such by grounding it.
 
First, let me say, ?welcome to the forum.? To that I will add, ?congratulations on your efforts to learn, especially when you hear things that contradict what you thought you already knew.?

As others have already said, you have brought up a common misconception. But it?s even more common than you might imagine. I had worked as an electrical engineer for three decades, had both BS and MS degrees in electrical engineering, was licensed as a professional engineer in a dozen states, and I still held to the notion that current seeks the shortest path to ground. I first heard that notion in my teen age years, from my oldest brother, a physics major in college and an electronics technician by trade. Ya gotta believe what your oldest brother tells you, right?

You want to know when I finally woke up to the nonsensical nature of that notion? About four years ago, when I attended a Grounding and Bonding seminar led by Mike Holt. Up to that point, the (fictitious) notion that current seeks its way to ground never bothered me, because it never entered into any design, analysis, operations, or construction support activity related to my employment.

So, keep learning, keep asking questions, keep seeking to confirm the truth of what you are being taught. It is the day that you think you know it all that will be the day you become dangerous.
 
Thanks

Thanks

Thanks to everyone for explaining and reconfirming what I was taught. I will continue to ask any strange questions I have, as my teacher seems far more knowledgeable that all the rest, and I'm sure will teach some other things that will leave me having doubts.
Thanks again
 
To dispel the myth of electricity trying to get to ground, I use the following example. Let's go out to your car/truck and open the hood. We will probably find a 12-volt battery. Lets hook one lead for a 12-volt light bulb to the positive terminal on the battery. The other lead on the light bulb will be connected to a ground rod. How many rods will I need to install before the light is lit? The answer is that it will never light unless I make a connection to the negative terminal of the battery. Electricity will take all available paths to return to its source. Since our services and utility supplies are all referenced to the earth by grounding, one of the available paths is through the earth. If I have a ground rod with 25-ohms resistance and connect a 120-volt conductor directly to the rod, how many amps will travel in the circuit? 4.8 amps. This is not enough current to trip a breaker. But since it only takes about .1-amp to cause serious problems in the human body, I do not want to hold that conductor in my hand while touching the ground rod!
The example that you gave with the 2000' conductor would be true IF the utility supply was not referenced to ground. No return path, no danger of shock. The reality is that our electrical systems are grounded, so I would not be willing to touch that live conductor. Remember it takes MUCH less current to kill or injure you (.1 amp or so) than it does to operate an overcurrent device.
 
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