PUD Educational Material

When trying to explain complex concepts to a layperson, it's best to keep it as simple as possible, even if it's a bit of a story...This explanation is no doubt aimed at elementary school level...Trying to explain electricity to somebody is a frustrating and time consuming undertaking at least...If I was transported back in time a couple of thousand years, just knowing that you can generate a current with a magnet and piece of copper, why I could rule the world....If I wasn't beheaded for sorcery first.(sic)

It happens more often than people may realise, and sometimes simplifying the answer too much causes more confusion in the learning process, not less.

For example, we had a (high school equivalent) science teacher at our school that got it all wrong and taught that light shone out of a persons eye, struck an object and flew into the nearest light point source.

Apparently she misinterpreted the arrow direction in a picture in the science book which showed a diagram with arrow directions on the light path.

Superman we ain't.

_{Jack - Seems to be using the word 'ain't' a lot this week.}

But after entering the light fixture, where does light go to?

Very true! Over-simplification results in over-confusion. In one of my training sessions, I remember, one participnat asked me, if current returns through the neutral back to the source, then why should he pay the Utility? Meaning, if he has drawn 10 Amperes thro the phase wire and instantaneously returns the same 10 Amperes through the neutral wire, he asked, why should he pay the Board. Now, what do you say for this?

You are paying the utility to rent the power they have, hence it needs to flow back in a timely manor or they cut you off.

Either that or go into a technical discussion regarding current flow, power and ohms law.

It's bollocks?

I go from point A to point B and come back to point A - Why do I spend petrol?

replace I with the 'I' and petrol with the Energy.

Quote ""Why does electricity try to get to the ground, and what does it do when it gets there?
It's just the nature of electricity to move from an area of higher voltage to an area of lower voltage, if given a path to travel there. The ground is simply the lowest-voltage area around, so if you give electricity a path to the ground, it will take it, no questions asked! When electricity goes into the ground, the earth absorbs its energy."

It is not trying to get to "GROUND". It is trying to return to the source. It takes numerous paths in its route back. The earth does not absorb any energy when speaking of this return.

Wiki's definition of electrical grounding is as follows:

"In electrical engineering, ground or earth may be the reference point in an electrical circuit from which other voltages are measured, or a common return path for electric current, or a direct physical connection to the Earth.

Electrical circuits may be connected to ground (earth) for several reasons. In mains powered equipment, exposed metal parts are connected to ground to prevent contact with a dangerous voltage if electrical insulation fails. Connections to ground limit the build-up of static electricity when handling flammable products or when repairing electronic devices. In some telegraph and power transmission circuits, the earth itself can be used as one conductor of the circuit, saving the cost of installing a separate return conductor."

We use the term "GROUND" very loosely. As stated ground is an intentional connection to earth or something that takes the place of earth. We use ground when we should be using the term bonding. When we make connections to metal objects that are part of the electrical system, the term bonding should be used but earthing and grounding is a common description of this action.

Comments are welcomed

I agree completely with what you wrote. It is staggering in the extreme the number of electrical people (both trades and engineering) who do not have even a beginning grasp on what the difference is between the two, grounding and bonding that is.

I am very pleased with the work that has gone into the Canadian code over the years to cleraly and concisly identify the differences between the two. I wish the NEC would follow suit. While by no means an expert on the NEC, in fact the word "neophyte" is more like it, from what I understand the terms "grounding", "grounded" and "ground" appear many times in the body of the US code where the terms "bonding", "bonded" and "bond" should be used instead.

The Earth absorbs nothing and should really be viewed as just another conductor!

So you are saying that the earth/ground is a perfect conductor with zero resistance to current flow and that none of the energy is converted to heat?

Are you asking this of me?

If so... of course not.

No, if you look at the upper right corner you will see that the comment was directed to reply #3. The point is that in the real world energy is lost all along the current flow path including the return path through the earth (as in the dirt we walk on). It maybe be a small amount but it is a loss nonetheless.

Ya... I understand that your question was related to comment #3. It is just that I did not see how your question tied into what Wareagle said and as such, I assumed your question was meant for me.

Anyhow... The energy is not lost to the earth, the energy is consumed in the "pushing" of the current through the earth and it is the prime mover that generated the energy in the first place that consumed it.

The fact the earth absorbs the heat generated by the current flow is not the same thing as the earth absorbing the energy itself.

I beg to differ. The earth resists the flow of current and the result is the conversion of EMF/voltage to heat. I don't understand your reasoning for saying that the earth does not absorb the energy. I agree that the power company's equipment is the source of the energy and the consumer pays for the amount of that energy/work that is consumed. The charge includes loss of energy through the transmission medium (the wires and the return path through the earth) but as far as I know the only medium that can conduct a loss-less current is a superconductor whose loss is transferred to the cooling requirement.

The earth "absorbs" the energy as much as the wiring "absorbs" the energy. The point is that the earth is not a huge ion bucket where particles just go and hang out.

The trouble is that we aren't aware but it is (huge ion bucket).

Check these two aspects - there are lot of literature on these (including wiki of course)

- Telluric Currents

- Electrostatic field of atmosphere - this can be even something like 100V/m near earth.

Infact there is a book on earth's electrical environment which deals with all these aspects.

Your statement is off topic - no one is addressing ions or plasmas. The statement was that the earth acting as a ground return path absorbs none of the energy from the current returning to the power supply station via the earth. According to the physics and EE courses that I took at Auburn University, electrical energy in a circuit is transferred from electron to electron or as movement of free electrons and all real conductors cause an energy loss that appears as an increase in conductor temperature, i.e. entropy increases in all real processes. I think everyone is off on a tangent from the original post. The statement in the contested info should have stated that the electric current from the power supplier returns to the supplier via an earth pathway and that some of the energy is dissipated in the conductor (metal wires) that transport the energy to the consumer, most of the energy is consumed by the customer's electrical devices (A/C, water heater, stove, TV, lights, etc.), and a small amount is lost on the return path through the earth (dirt). Electricity always follows the path of least resistance but it doesn't require zero resistance.

I agree with you. My point is...

If the earth absorbed electrical energy from the passage of the current through it, there would be a noticeable change in the electrical state of the body of the earth.

But that is not what happens, the earth absorbs energy from the heat of the passage of the current through it so it sees a net gain in energy. Which is what I think you are driving at. But the net gain in energy in the body of the earth is the result of the transfer of thermal energy to the earth and not the absortion of electrical energy by the earth.

In any case... this has been an interesting discussion. Of which there has been a lack of of late.

There are changes in the state; however, the changes are so rapidly balanced out in less than a millisecond that they are not noticeable, and also since the difference to be noticeable would be over a huge expanse.

An easy example would be the huge expanse of water which across Africa isn't at same level forcing lift locks at Panama, but if one sails across the cape, he won't feel the lift.

Across the earth's crust there is a huge amount of current flowing, usually natural, till we (human's ) modify it by our actions.

Joe

You are absolutely correct. There is a move on to change that in the code. I hope it will be in the next edition.

As the CANENA process (the tri-national harmonization efforts) and other the various harmonization efforts continue to roll along, the differences between them, the CEC and the NEC, get less and less each code cycle.

Lets hope the changes happen sooner rather than later.

Rick...

Somebody was looking over our shoulders when we likened electrical properties to the properties of water.

Kuduk

<...When electricity goes into the ground, the earth absorbs its energy....comments?...>

It's bollocks?

Like anything else - It is all relative, a matter of relativity. In any electrical circuits, a return path is needed, not necessarily via earth, to complete that particular circuit loop. Generally utility companies uses the earth, commonly called and labeled as "ground" used as their main reference point for better power control or regulation as well as for safety purposes. Safety since all of us are referenced - standing on the same point commonly called as ground. In automotive, the chassis of the cars are used as the main return path or conductor to complete its own local electrical circuits. The same holds true to any electrical /electronic devices that at times needed to be "grounded" to eliminate unnecessary and unwanted electrically induced noises.

I hope to write a nicely worded letter to the PUD to point out this error..."lowest voltage area around"...yikes

It's kind of funny, though, because other parts of the FAQ describe the need for a circuit...then goes on to this "magic sponge" theory.

There are two 'l's in 'bollocks'.

Food for thought - The self capacitance of earth as conducting sphrere is only 0.71 mF.

It means just a few coulombs would increase its potential by quite a few volts (in fact hundreds). Does it happen? remember all the charges that are deposited to teh earth don't have a returm path, at least not instantaneous, some of the charges are brought back slowly by diffusion. But even in that case the potential of the reference really doesn't rise by that much.

There are a few other thins at play here going further beyond the simple return path circuit and it has a flavour of what the PUD said (though still what it said isn't true).

If the earth absorbs the energy of all of the electrical systems in the world that use it for an electrical path it would contribute to global warming and the tingling feeling in my dog's feet.

Kuduk