How does the typical mains power connect in the USA anyway?

[Danny D'Amico]

Nope. You saw the references. They were all for standard power distribution in the United States.

For example, this reference from Smith College, Northampton, MA:

Says: "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."

That's from an EE class:

EGR 220, Spring 2013, Engineering Circuit Theory

Taught by Judith Cardell, who researches this stuff:

So, why do you constantly disparage my comments when I can easily prove that exactly what I have said all along is being taught to electrical engineers in college-level courses?

All I'm asking is for you to provide a reference that refutes the statement above. You can *say* you don't believe it all you want; but, all I ask is a single reliable reference backing up the claim that the power company does *not* use the ground as the a "good return path for electrons".

[gfretwell]

Sayin' but not readin'.

I said you could have a bare grounding conductor in a raceway , not a neutral, (beyond the service disconnect) Before the service disconnect the neutral can be bare.

[Danny D'Amico]

This reference from Smith College, Northampton, MA:

Says: "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."

That's from an EE class:

EGR 220, Spring 2013, Engineering Circuit Theory

Taught by Judith Cardell, who researches this stuff:

She should know, shouldn't she?

[Danny D'Amico]

This reference from Smith College, Northampton, MA:

Says: "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."

That's from an EE class:

EGR 220, Spring 2013, Engineering Circuit Theory

Taught by Judith Cardell, who researches this stuff:

She should know, shouldn't she?

[Danny D'Amico]

You're getting too personal. This is not a personal issue. We are all among friends here. This is merely a discussion about what the TRUTH is.

I don't see a single reference in all your posts which state that the earth is not used as the return path for electrons in typical American power distribution.

In contrast, I have provided a half-dozen references which directly state that the earth is used as the return path for electrons in power distribution in the United States.

For example, read this reference:

Which states, clearly as the sun shines on the truth: "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."

This is from this electrical engineering class:

EGR 220, Spring 2013, Engineering Circuit Theory

Taught by this associate professor:

Again, this is not a personal issue. I don't care if I'm right or wrong. I don't care if you are right or wrong.

I just want to know what the truth is. And, if this EE class is wrong, then I would think we can find a single reference that refutes the statement I quoted.

I can't find any. No matter how hard I look. Can you?

[Danny D'Amico]

I loved your description. It was an elegantly written logical thought process. I like the way your mind works!

To clarify this important issue, this is what I found: "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."

That was found in an EE class taught by this associate professor:

This is the EE class where that concept is being taught:

EGR 220, Spring 2013, Engineering Circuit Theory

That statement above is part of the curriculum on power generation and distribution in the United States:

So, like you, since the fact the ground is used as the return path for electrons seems to be as clear as day, I wonder why there are vehement arguments (some of which are getting unnecessarily personal) that it's not.

I'm ok with the answer being either way. I don't care who is right and who is wrong (and I'll admit when I'm wrong any time that I am).

But, this one seems clear as the earth revolves around the sun.

But, maybe I'm wrong. Maybe the earth is *not* used as a return path for electrons back to the power company.

Q: Can anyone find a reliable reference that refutes the statement above (taught in EE classes) that the earth is used as a return path for electrons back to the power company?

[Tony Hwang]

Hmmm, You are trying to say if I and V is out of phase by certain degree there will be a current flow which is wasteful. That current does not do any work. That is why in big industrial site or buildings use power factor correction device.

[gfretwell]

Nothing. A small amount of the unbalanced neutral current does go back through the ground. You can see it on the ground wire going up the pole to the XO on the pole pig.

This is the voltage drop across the service cable from the pole to the house. There is also quite a bit of voltage drop on the primary and that shows up through the ground wire. This is the first pole on the street.

[Danny D'Amico]

That is a gorgeously illustrative picture!

I see 860mA of current going through that wire into the ground on your side of the transformer.

I presume 860mA would be considered indicative of a reasonably well balanced set of loads inside your home?

Another beautiful picture! Is that 142mV RMS? If so, there's essentially no voltage drop from the transformer to the home. Right?

That picture seems to show 2.95A flowing through the ground wire!

If that is on the primary side, wouldn't *that* be the current which is (essentially) flowing back to the power company?

[gfretwell]

There is some incidental current going back through the ground but there is also a neutral wire on the pole wherever you have wye distribution.

They use delta distribution on the long haul lines so there is no real ground current.

[gfretwell]

Since this is wye distribution, it would be reconciled at the transformer that steps down the HV to MV where it goes to delta distribution but some of that would just go to the next series of poles on the other primary phases.

[nestork]

No, houses very rarely have power factor correction. Most of the reason why is that electrical utilities only charge their residential customers on the actual kilowatts they used, not the KVA the consumed. So, why have power factor correction if it's not going to save you any money on your electric bill?

I'm saying that in the real life situation, electrical loads being carried by L1 and L2 are rarely ever going to be perfectly balanced. The result is always going to be some timing differences in the current sine waves travelling in the white wires returning to the electrical panel. The result is going to be a "net current sine wave" as a result of superposition of all the individual current sine waves in the neutral buss in the main panel.

You can't have current without voltage. Ergo, there is always going to be some net voltage sine wave in that neutral buss, and therefore in the ground wire cable coming out of the main panel. So, how can you NOT have current into and out of the Good Earth through the grounding rod or pipe if there is a voltage imposed on that grounding cable by the white buss?

I'm not saying that current flows back to the generating station through the ground. Or, at least, I'm not saying that yet.

I'm saying that electrical loads are rarely going to be perfectly balanced, and any imbalance in the impedance of electrical loads is going to cause timing differences in the amperage sine waves carried by the white wires connected to the neutral buss in the main panel. That means there HAS TO BE some net voltage sine wave in that neutral buss to drive that net current sine wave.

And, I can't see why a net voltage sine wave in the neutral buss wouldn't cause current flow into and out of the Good Earth at the grounding rod or plumbing pipe.

And, according to one of the pictures posted by G. Fretwell, the current measured through his grounding rod is 0.142 amps. And that's without any intentional effort to imbalance the electrical load at the main panel.

Where am I wrong there?

[clare]

She is referring to the "safety groun d", not the neutral, or she is "dumming it down". It IS still used as a ground return on a VERY small basis in very limitted locations - as SWERT.

She SHOULD know, but obviously is not expressing her knowledge very well.

[clare]

That is definitely NOT college level electrical engineering. Looks like a junior college introduction course to me.

[clare]

In DISTRIBUTION, yes - but not on the "consumer" side.

[clare]

Note the "essentially" - it is not "litterally"

[Danny D'Amico]

I always thought they only measured current at the meter?

Agreed.

:)

Exactly!

When it gets light, and I take care of the grandkids getting to school, I'm going to see if I can find my old ammeter and I'm going to check my neutral and ground wires too!

Those pictures from gfrewell were inspiring! We can make our own observations!

[clare]

You are only giving ONE reference for your position - associate professor J Cardell..

And many of us are saying she is not totally correct.

[Danny D'Amico]

This PDF, which is all about neutral and ground currents, says repeatedly there is no current flowing in the neutral for 240V loads; but that there is, in practice, always some current flowing in the neutral of 120V loads.

However, I never quite understood why or when they use the delta versus the wye so, I'm reading up on that as we speak.

It's interesting that the neutral is lower than the power in that I would have expected that ... but ...

Here, the neutral is *above* the power lines. I would not have expected that! :)

I wish I understood why/when they use delta versus wye.

At the moment, I don't yet understand the effective difference between the two, other than that to transform the voltage, you need to start with either one and then use the other on the other side.

But, which one you start with, and which you end up with, always confused me as to the why... but I'm digging further into that.

[dave]

Modern polyphase power has no ground for reference. This is a major pain in the ass when trying to find 120Vac on top of a mountain.