Talk:Speed of electricity

Some references on Hertz

After discovering electromagnetic waves, Hertz studied the question whether the electromagnetic waves ("space waves") travel at the same speed as the disturbance in the wire ("wire waves"). He initially found a discrepancy, but the more controlled experiments by Edouard Sarasin and Lucien de la Rive in 1893 established that both travel at same speed. Some sources discussing this:

• Yeang, Chen-Pang (2024-01-30). "Electromagnetism and Electrodynamics in the 19th Century". Oxford Research Encyclopedia of Physics. Oxford University Press. doi:10.1093/acrefore/9780190871994.013.131. ISBN 978-0-19-087199-4. Retrieved 2025-12-19.
• Darrigol, Olivier (2003). Electrodynamics from Ampère to Einstein. Oxford University Press. pp. 247–251. ISBN 978-0-19-850593-8.
• Buchwald, Jed; Yeang, Chen-Pang; Stemeroff, Noah; Barton, Jenifer; Harrington, Quinn (2021). "What Heinrich Hertz discovered about electric waves in 1887–1888". Archive for History of Exact Sciences. 75 (2): 125–171. doi:10.1007/s00407-020-00260-1. ISSN 0003-9519.

Jähmefyysikko (talk) 09:55, 19 December 2025 (UTC)

 Done thanks I added a paragraph to History, please review. Johnjbarton (talk) 19:48, 12 January 2026 (UTC)

In general, electrons propagate randomly in a conductor at the Fermi velocity, and the Fermi sphere.

The article says: In general, electrons propagate randomly in a conductor at the Fermi velocity. The electrons fill up the Fermi sphere in momentum space. Random seems like it means some random subset of the possibilities. Ground state is the Fermi sphere. At ordinary temperatures, the boundary is fuzzy, but otherwise still a sphere. For a current, the center of the sphere moves slightly, such that the average is not zero. Gah4 (talk) 08:02, 23 December 2025 (UTC)

I agree that "In general" is a poor choice and I'll change it. Johnjbarton (talk) 16:27, 23 December 2025 (UTC)

WP:EXTRAORDINARY

I would characterize the following passage from the article as an "extraordinary claim":

The energy or signal usually flows overwhelmingly outside the electric conductor of a cable. The purpose of the conductor is thus not to conduct energy, but to guide the energy-carrying wave.

Anyone who has ever done basic house wiring knows that you need to use properly sized wire to accommodate the expected current flow. e.g. in the US, that means using 12AWG for 20 amp circuits and 14AWG for 15 amp circuits. Moreover, the "energy flow" is neatly described by ohms law as Power = voltage x amperage. For ordinary household wiring, the current flows inside the wire, not on the outside.

Looking at the cite - which is the only one provided, in contrast to the multiple cites required by WP:EXTRAORDINARY, the relevant material is related to transmission lines. I don't dispute the cite - what it says is applicable to transmission lines, i.e. circuits where the length is near or greater than the wavelength.

But for the usual wiring that is encountered by ordinary people every day, modeling the circuit as a transmission line is not a good model. Take a look at this paper Transmission Lines at Audio Frequencies, and a Bit of History which goes into detail about characteristic impedances and propagation speed at audio frequencies, and note that the 50 or 60 hz mains commonly encountered is at the low end of the audio spectrum. While this article doesn't directly refute the claim above, note that both it and the cited source are clear that for short distances and low frequencies a circuit does not act as a transmission line.

And since the passage above is based on language in the source re transmission lines, it's not generally applicable.

IOW, try to tell any working electrician that "the energy flows outside the wire" and that you don't need a large conductor to carry substantial current since the conductor is just there to "guide" the energy, and I think you would realize how extraordinary this passage is.

Since the talk page is supposed to be about how to improve the article, rather than discussing the topic itself, my strong suggestion is to simply remove that passage. It's not directly related to the topic at hand - i.e. the speed of the signal or energy flow, as opposed to its distribution. And if we're going to present this idea, it should be explained more thoroughly, with multiple cites, and probably in a different article.

I understand that we discussed this earlier, but the previous discussion ended with wikilawyering about how we can't remove it without consensus, which is not how things work. See WP:ONUS for example. So, if you think this material should remain, please show your sources that clearly support this extraordinary claim. Mr. Swordfish (talk) 02:05, 1 May 2026 (UTC)

Standard Handbook for Electrical Engineers, 11th Edition, Fink, Donald G. editor, McGraw-Hill

Chapter 2, Section 40,

Page 2-13, "The energies stored in the fields travel with them, and this phenomenon is the basic and sole mechanism whereby electric power transmission takes place. Thus the electrical energy transmitted by means of transmission lines flows through the space surrounding the conductors, the latter (conductors) acting merely as guides.

"The usually accepted view that the conductor current produces the magnetic field surrounding it must be displaced by the more appropriate one that the electromagnetic field surrounding the conductor produces, through a small drain on its energy supply, the current in the conductor. Although the value of the latter (current) may be used in computing the transmitted energy, one should clearly recognize that physically this current produces only a loss and in no way has a direct part in the phenomenon of power transmission."

Stratton, Julius Adams

Electromagnetic Theory, McGraw-Hill, 1941

Page 533, "The transport of energy along the cylinder takes place entirely in the external dielectric. The internal energy surges back and forth and supplies the Joule heat losses.

Kraus, John D.

In Fig. 10-60a flow lines of the Poynting vector (power flow lines) are shown. It is evident, that the power flow is in the empty space surrounding the circuit, the conductors of the circuit acting as guiding elements. From the circuit point of view, we usually think of power as flowing through the wires, but this is an over simplification and does not represent the actual situation. Constant314 (talk) 02:53, 1 May 2026 (UTC)

It is not extraordinary, it is just surprising to people who have not studied electromagnetics. It is a direct consequence of the definition of the Poynting vector. It applies to all wiring all the way down to DC. Hayt's textbook is used for a first course in electromagnetics. Constant314 (talk)

Feynman regarding Examples of energy flow, "As another example, we ask what happens in a piece of resistance wire when it is carrying a current. ... . . There is a flow of energy into the wire all around. It is, of course, equal to the energy being lost in the wire in the form of heat. So our crazy theory says that the electrons are getting their energy to generate heat because of the energy flowing into the wire from the field outside. Intuition would seem to tell us that the electrons get their energy from being pushed along the wire, so the energy should be flowing down (or up) along the wire. But the theory says that the electrons are really being pushed by an electric field, which has come from some charges very far away, and that the electrons get their energy for generating heat from these fields. The energy somehow flows from the distant charges into a wide area of space and then inward to the wire.

... that the energy is flowing into the wire from the outside, rather than along the wire. "

Constant314 (talk) 02:29, 1 May 2026 (UTC)

Well, not all of our readers have done graduate work in E&M, worked as a transmitter engineer, or provided electrical service to major rock concerts like I have. And if I can't follow the argument, then they won't either.

The point of this whole exercise is not to show how smart and learned we are, it's to effectively communicate and explain the material to our readers. And the "drive by" passage above, stated without explanation, as a non-sequitor that is not even germaine to the topic at hand, does a disservice to our audience.

If we're going to keep it, we need to do a better job of meeting our readers where they are. Perhaps you have some language in mind that might place this "surprising" statement in context. Or could suggest a more appropriate article for its inclusion. Mr. Swordfish (talk) 02:53, 1 May 2026 (UTC)

Too complicated for the reader and needing a better explanation are a valid concerns. By the way, this is undergraduate E&M. The Feynman were directed at incoming Freshmen. Constant314 (talk) 02:57, 1 May 2026 (UTC)

You say it's "surprising". Fenyman says it violates our intuition. Perhaps "extraordinary" is too strong a term, but simply dropping a surprising, counterintuitive assertion into an article about something else without providing context or further explanation is poor pedagogy.

Wikipedia is not a "how to", but we don't want someone rewiring their house with 22AWG wire since they read on Wikipedia that the conductor is "just a guide" and the energy flows outside the wire. Mr. Swordfish (talk) 03:14, 1 May 2026 (UTC)

The Feynman lectures are transcripts of actual lectures. Feynman often used rhetorical devices to direct the attention of thew audience. Thus, he may say that something violates the intuition of the audience (incoming freshmen) and then spends the rest of the lecture showing why it works. Hearing unintuitive facts is part of the learning process. There is no need to protect Wikipedia readers from unintuitive facts. Constant314 (talk) 15:59, 1 May 2026 (UTC)

If we present unintuitive facts, then it's on us to explain those unintuitive facts.

The passage above is woefully inadequate. Mr. Swordfish (talk) 17:01, 1 May 2026 (UTC)

Let's review what the cited source says on page 391, section 14.4.2 Skin Effect. The full paragraph is:

At a microwave frequency of 10,000 MHz, δ is 6.61 × 10−4 mm. Stated more generally, all fields in a good conductor such as copper are essentially zero at distances greater than a few skin depths from the surface. Any current density or electric field intensity established at the surface of a good conductor decays rapidly as we progress into the conductor. Electromagnetic energy is not transmitted in the interior of a conductor; it travels in the region surrounding the conductor, while the conductor merely guides the waves.

Note the context of a 10,000MHz signal and the statement that the fields are "essentially zero at distances greater than a few skin depths from the surface". For a 60hz current, the skin depth is about 8mm, which is far larger than any household wiring. So, the conclusion that the fields inside the conductor are zero does not follow, and the broad statement copied into this article is inapplicable to common 60hz household electric service. It's also inapplicable to DC, where there is no skin effect. The article as it stands now implies that for all electric energy flow through wires the energy flow is outside the conductor. That is taking the quote from Hyat out of context.

Since the cite takes the source out of context, it fails verification, hence the tag that I added which was summarily reverted. Similarly, the articles cited above seem to be discussing transmission lines, not circuits where the length is larger than the wavelength.

The bigger problem with the passage is that it's irrelevant to the topic at hand. Why does it belong here when it will "surprise" most of our readers? The common analogy for understanding electricity flow is that it's like water through a pipe; while this model has serious limitations, it's how most people understand it. When our readers come to this article and read something akin to "actually, the water flows on the outside of the pipe" they experience a surprising and counterintuive statement, given without context or explanation, along with a cite that doesn't establish the claim.

The passage should just be removed. I have yet to hear a good reason for keeping it, other than that it's been in the article for a long time, which is not a good reason. Mr. Swordfish (talk)

• The article as it stands now implies that for all electric energy flow through wires the energy flow is outside the conductor. Yes, the article does imply that, and yes it is a correct statement.
• The fact that Hayt chooses examples of 60Hz and 10MHz in no way restricts the applicability to other frequencies including DC.
• Kraus includes the case of a DC circuit fed by a battery.
• Feynman includes the static case of a static charge and a permanent magnet.
• The reason for including this is that it explains why the speed of electricity is controlled by the dielectric material surrounding the conductor. It bears directly on the subject of the article.Constant314 (talk)

Question: is the energy flow in a circuit carried by the electromagnetic fields surrounding the conductor, or by the charge carriers (i.e. the electrons) inside the conductor? The Poynting Vector approach correctly quantifies the the energy flow, I'm not going to dispute that. It's also possible to quantify the energy transfer rate via Ohm's law: P=E*I. This is a much simpler, less sophisticated analysis, but it gives the right result. Is it "wrong" to think about it that way, i.e. that the energy is carried by the electrons?

If the answer to that question is "yes", then we should carefully distinguish between energy flow and electron flow (i.e. current). I think we can agree that the current flows inside the conductor and that the E&M fields are mostly outside the conductor, and for radio frequencies the E&M fields almost entirely on the outside of the conductor. Depending on how one conceives of the energy flow (conducted by the fields or the carriers), the passage can be interpreted incorrectly.

My impression is that most of our readers will assume that the energy is being carried by the electrons; saying that this occurs outside the conductor will be surprising to them.

One possible solution is to sidestep the whole "energy transfer" question by modifying the first sentence to say

The energy or signal usually flows overwhelmingly outside the electric conductor of a cable. The purpose of the conductor is thus not to conduct energy, but to guide the energy-carrying wave.

Returning to the fields or carriers question above, I'm not seeing a good treatment of that anywhere on Wkikpedia. I think it would make for a good discussion on the Electric current page, and we could link to it here.

One more thing: although any electric circuit must transfer some energy to be a circuit, the purpose of the majority of electric circuits is to carry a signal as opposed to transferring energy. Seems to me that this article is about how fast the signal travels, rather than whether energy transfer is the "purpose" of the conductor, and discussing energy transfer poses more questions than it answers. Mr. Swordfish (talk) 17:53, 1 May 2026 (UTC)

First, I do hope we are surprising readers, otherwise they don't need to read the page! Lots of things going on here.

• The fields or carriers question is a false dichotomy. Fields are created by the electrons and fields cause the electron motion that cause the field.
• Power is not energy, so P=E*I is not relevant to speed of electricity.
• energy flow and signal flow are synonymous along a wire.
• I agree that "purpose" is not correct.
• Poynting vector describes the energy of the EM field, it says nothing about the electrons. They are connected because the Poynting field near the wire points into the wire, where the energy is dissipated as heat and because the large scale Poynting field indicates energy flow in a circuit. But the steady state Poynting field of say a battery powering a light bulb does not tell us about the speed of electricity.
• The speed of EM waves on a conductor depends upon environment (L and C) and on frequency. When we launch a square pulse into a circuit the field builds up over time in a non-square wave fashion.

I hacked on the paragraph, please review. Johnjbarton (talk) 01:34, 2 May 2026 (UTC)

Your input is always welcome, but I have reverted it for now. First, you have obliterated the simple statement that energy flows outside the conductor. That is fine if we decide by consensus to remove the statement. Second, you said, By definition, an electric conductor has no internal electric fields. That is approximately true when the frequency is high enough that there is a well developed skin effect, but we are considering powerline frequencies. If there is current flow in the conductor, there must be an E field in the conductor pushing the current along. Constant314 (talk) 02:05, 2 May 2026 (UTC)

I summarized the sources given. What are your sources? Johnjbarton (talk) 02:13, 2 May 2026 (UTC)

In addition to Hayt and Feynman I listed four others earlier in this discussion. Constant314 (talk) 02:17, 2 May 2026 (UTC)

Thanks, I'm sorry I didn't read from the beginning. But I'm confused. The Fink, Statton, Feynman, Krass quotes you added align with what I thought I wrote.

From your previous post, it seems to me that "energy flows outside the conductor" contradicts "there must be an E field in the conductor pushing the current along". While I would like to read a source on the second one, I don't think it relates to this article.

I'm ok if we start with something like:

• The energy or signal measured as the speed of electricity flows outside the electric conductor of a cable.

I don't like 'usually' and 'overwhelmingly' because these contexts are not explained and IMO are not really germane to the topic. So instead let's eliminate the other cases by constraining the discussion to the article topic.

I don't like the phrase

• The purpose of the conductor is thus not to conduct energy,

because it is not true and not supported by sources. The conductor has others purposes, eg hosting the electrons that create the field, dissipating heat.

I think the sentence

• The propagation of the wave...

is overly complicated but more important we should try to get across the interactive nature of the field, charges, field, charges, which I tried to do.

The final sentence

• These interactions are typically...

is unsourced and not helpful. Johnjbarton (talk) 03:05, 2 May 2026 (UTC)

I agree about that last sentence. It is an unhelpful factoid if true.

As for your confusion, yes there is some mixing of models.

• If the conductors are ideal, then all the energy flows outside the conductors and there is no field inside the conductors. This is a useful approximation.
• If the conductors have resistance, then all the energy that makes it to the load flows outside the conductor. The energy needed to account for ohmic heating flows into the wire from the outside. It penetrates to about one skin depth. This is the reason for saying overwhelmingly.

Constant314 (talk) 03:42, 2 May 2026 (UTC)

So now you and I, and anyone reading your comment knows what overwhelmingly means. But we want the readers of the page to know. An "usually" still makes no sense. Johnjbarton (talk) 16:20, 2 May 2026 (UTC)

I do not oppose improving the article by improving the explanation. I do oppose removing the fact that the energy flow is external to the conductor because that explains why the the speed of energy delivery is controlled by material properties that are external to the conductor.

How much explanation is appropriate for this article? I am not sure. I like to give the reader a thought provoking, surprising and relevant fact, but want to avoid the firehose effect. I will think on it. Constant314 (talk) 17:04, 2 May 2026 (UTC)

@Johnjbarton (talk), Thanks for your thoughtful reply. I think your edit to the article was an improvement and was disappointed that it was reverted. But there's a process to be followed, and I am optimistic that we can reach consensus regarding improving the article. Some comments:

I don't like the phrase

The purpose of the conductor is thus not to conduct energy,

because it is not true and not supported by sources.

Thank you for succinctly stating what I was trying to say in the wall of text above.

I'm ok if we start with something like:

The energy or signal measured as the speed of electricity flows outside the electric conductor of a cable.

That looks good. I'd suggest the following edit:

The energy or signal measured as the speed of electricity is conveyed by the electric and magnetic fields which extend outside the electric conductor of a cable.

We could then add that inside a perfect conductor the electric field is zero, and that it is small inside real-world conductors.

The fields or carriers question is a false dichotomy. Fields are created by the electrons and fields cause the electron motion that cause the field.

That's my understanding as well, although I've seen it said that the "carriers" explanation is a misconception. This article is probably not the appropriate venue for treating this material, so simply stepping around it is probably best.

Power is not energy, so P=E*I is not relevant to speed of electricity.

P=E*I is a way to calculate energy transfer rate, so it's at least related to energy flow, but agree that it's not relevant to the speed of electricity.

energy flow and signal flow are synonymous along a wire.

Energy flow and current flow are not. My impression is that many of our readers might come to the article thinking that they are synonymous and get the impression that the article states that the current flow is outside the conductor. Let's make sure we don't leave that impression by opining about the "purpose" of the conductor.

The speed of EM waves on a conductor depends upon environment (L and C) and on frequency.

Yes, and I think we need to state that more clearly in plain prose for our non-technical audience. In particular, this paper, Transmission Lines at Audio Frequencies, and a Bit of History, shows that for a typical cable, the speed converges to about 2/3 the speed of light with increasing frequency and is mostly there by 100khz or so. Meanwhile, at 60hz it's only about 1/3 c. We should review the lead section and the material at Velocity factor which seems to tacitly assume radio frequencies as opposed to audio frequencies and 50/60hz mains power.

From a practical perspective, for RF work the speed is basically constant, at audio frequencies the speed variations are irrelevant unless your cable is many kilometers long, and for 50/60hz power the frequency is fixed so variations are not a thing. Not sure how much of this belongs in the article however.

..electrons in the outer surface of the conductor...

This phrase is from the reverted edit; my take on the back and forth discussion above is that we don't need to tread the skin effect in this article about the speed of electricity. At 60hz, there is no skin effect while at RF there is. Do we really need to make this distinction? Seems like a distraction, and simply removing the word "outer" seems to resolve the issue.

Looks like we're making progress, and I already see a couple of edits that I think are improvements. Thanks to both of you. Mr. Swordfish (talk) 19:42, 2 May 2026 (UTC)

I reworded that phrase about the purpose of the conductor. I hope it is more palatable.

• I agree on avoiding mention the skin effect. At 60Hz for ordinary house wiring it can be ignored. For larger conductor power transmission lines, it is signifiant.
• I want to avoid L and C because we have to explain what L and what C.
• I want to avoid ideal conductors because they would have a constant velocity down to sub millihertz frequencies.
• I want to avoid electrons as energy carriers because if the electrons going from the source to the load are carrying energy to the load, then what are the electrons coming from the load back to the source carrying?
• Poynting vector is unneeded. It only comes up as additional confirmation that the energy flow is out in the field around the wire.
• If you plot velocity vs frequency, there are two significant break frequencies: R/L and 1/(GC). On modern cables, G is so large that 1/(GC) is on the order of millihertz. R/L varies from low audio to low video. On long haul high power transmissions line big conductors mean R is small and wide spacing mean L is large. R/L can be surprisingly small. Upshot of all that is you have to be careful with generalities.

Here are a couple of plots that basically show that it is complicated. I don't want to put this into the article, but I also don't want to simplify the article to the point that these charts would be contradicted.

Ratio of G/ωC and R/ωL versus frequency for a typical RG-59 coaxial transmission line with a good (high resistivity) dielectric insulator.

Phase velocity of a typical RG-59 coaxial transmission line with a good (high resistivity) dielectric insulator relative to the speed of light in vacuum.

Constant314 (talk) 21:32, 2 May 2026 (UTC)

This is Feynman's summary. It is out of context. For context you have to consider the whole chapter.

Anyway, everyone always accepts the simple expressions we have found for the location of electromagnetic energy and its flow. And although sometimes the results obtained from using them seem strange, nobody has ever found anything wrong with them—that is, no disagreement with experiment. So we will follow the rest of the world—besides, we believe that it is probably perfectly right.

Of course, when Feynman says everyone he means physicists and people have been educated in electromagnetic field theory. Feynman is writing circa 1964.

Feynman goes on to say gravitational considerations point to the correctness of the view that the Poynting vector does represent energy flow, but no experiment to date is sensitive enough to test it.

• Jackson says, without equivocation, that ExH is the energy flow.

Constant314 (talk) 01:51, 2 May 2026 (UTC)

References

What is next

Is there more to hash out or are we happy? Constant314 (talk) 14:30, 3 May 2026 (UTC)

The recent changes are an improvement. Thanks. Some issues that I'd like to see addressed, or at least discussed further:

• John's statement that energy flow and signal flow are synonymous along a wire. seems correct. But is energy flow necessary to explain the speed? I don't really think it is, but if there's consensus to talk about both the energy flow and signal flow I'm ok with leaving both in the presentation.
• There seems to be a tacit assumption that we're describing high frequencies. For lower frequencies, the speed of electricity is below the "50 to 99%" figure quoted in the lead. Assuming that the article I posted and the graph you shared are correct, the speed at 60 hz is about 33% c, and for really low frequencies it's more like 10^-5 of the speed of light. Shouldn't the article reflect this?
• I'm not seeing discussion of the dependence on frequency in the text of the article. For RF, it's not frequency dependent, but for lower frequencies it is. We should acknowledge that in the article.
• a cable is a form of a waveguide. I think linking to Transmission line is more apt here. While some use the terms interchangably, other's restrict the waveguide term to hollow configurations without a center conductor.
• Moreover, the Transmission line states:

The term applies when the conductors are long enough that the wave nature of the transmission must be taken into account.

so we should include that caveat here.

• For the opening sentence of the third section,

Energy or signals from a source to a load or receiver are conveyed by the electric and magnetic fields which extend outside the electric conductor of a cable.

seems more descriptive than

Energy or signals from a source to a load or receiver flow outside of the electric conductor of a cable.

since it describes what is outside the conductor that is "doing the work". I don't think it is too complicated to also state something to the effect that "...electromagnegtic waves are strongly attenuated inside conductors" hence why they are almost entirely outside the conductor. (quote above taken ver batum from my old E&M textbook).

• I think the second graph you posted would be a great addition to the article.

That's all for now. Thanks for taking this into consideration. Mr. Swordfish (talk) 17:57, 3 May 2026 (UTC)

We can put that chart in if we have a strong consensus (three of three in this case). I made that chart by evaluating the full expression for velocity and some reasonable parameterizations of the primary parameters. Generating equations are: $C=C_{\infty },\,G=G_{dc}+\omega C\tan \delta ,\,L=L_{\infty }+\Delta L_{\omega }$ with $R{\text{ and }}\Delta L_{\omega }$ computed from a formula by Weeks as described in skin effect.

On a log-log scale, minor discrepancies of the parameterization equations makes almost no discernable difference. Constant314 (talk) 23:59, 3 May 2026 (UTC)

The aspect that still bothers me is crisp definition of what one measures to define the "speed of electricity". From the encyclopedia point of view, Baird covers the high points, but when he gets to signal velocity it is vague. The historical experiments charged a line and measured how long until an effect was observed at a distance. They got all manner of answers, because we know now that a well defined speed requires constant environment (LCR) and fixed frequency. So even in these experiments, which I take to define "speed of electricity", had roughly constant geometry, the exact manner of launching and detecting the effect would yield any value up to c.

Knowing this we might (and do without exactly laying in it out in the article) switch to constant frequency and report speed of electricity as group or energy velocity. My problem with this is that a 60Hz circuit will respond to transients orders of magnitude faster than 3 m/s we have in the article. In

• Martzloff, F. D. (1983). The propagation and attenuation of surge voltages and surge currents in low-voltage ac circuits. IEEE Transactions on Power Apparatus and Systems, (5), 1163-1170.

they measure 200 meters/microsecond for a 100ns pulse on a residential power line simulation. Isn't that the "speed of electricity" for a 60Hz system? What is the 3m/s?

Similarly, the classroom version of "speed of electricity", how long it takes to light a bulb, has much more to do with the bulb than the electricity. Johnjbarton (talk) 20:57, 3 May 2026 (UTC)

If we think about it long enough, it becomes like the Coastline paradox with no definite answer. But that doesn't stop us from listing reliably sourced data about coastline length. Let's not allow "over analysis" to get in the way of the article. Mr. Swordfish (talk) 00:01, 4 May 2026 (UTC)

I assume that the target level of this article is high school graduate, trade school technician, maybe college freshman. When I think speed of electricity I think, how long after I connect the source until there is energy at the load? Even if the source is DC, the startup transient is high frequency. The leading edge of the transient gets to the load at the high frequency velocity.

The frequency dependent velocity is mathematically interesting, but probably not helpful for an article at this level. Constant314 (talk) 00:15, 4 May 2026 (UTC)

? The way I read what you say is "the speed of electricity is frequency dependent but its not helpful to discuss that". I'm not convinced but neither do I have a source to use for that purpose. My problem is that the second major section of this article is "Electromagnetic waves" which is exactly a discussion of the frequency dependence of velocity you argue against. Then we fail to connect this to the "how long after I connect the source until there is energy at the load?" which I agree is the historical meaning of "speed of electricity".

To avoid more analysis, a concrete suggestion: reorg the article include 3 sections after History matching the 3 sections in Baird. That source is at the level you wish to target. "Conduction electron velocity" will be one of those. We can leave the "Electromagnetic waves" Johnjbarton (talk) 01:50, 4 May 2026 (UTC)

Do you have a link or a cite to Baird? I'm not sure what that is. Thanks. Mr. Swordfish (talk) 02:03, 4 May 2026 (UTC)

Currently citation #1, Speed_of_electricity#cite_note-cbaird-2014-1 Johnjbarton (talk) 02:48, 4 May 2026 (UTC)

Thanks. A text search for Baird comes up empty. It's an interesting read, and provides good sourcing for some of the things we cover, but I don't see any compelling reason to restrict our treatment to what's covered there. Or the "historical meaning" of the topic.

As for the target audience, I'd expect most readers to get as far as the lead, understand that the speed of electricity in a wire is a significant fraction but still less than the speed of light in a vacuum, and that the electrons themselves move very slowly. I'll be very surprised if many bother to read beyond that point. I don't think the dependance on frequency or the fact that the E&M wave that carries the signal is outside the conductor is important enough to put in the lead, but opinions can vary.

I do think that frequency dependance, as well as the dependance on L & C, are important enough to treat later in the article, and should be explained in words and graphs instead of just formulas.

Regarding frequency dependence, there's currently a lot of nonsense floating around the internet about how the speed differences at audio frequencies affect the sound, since 20khz propagates faster than 20hz. This article is not the venue for addressing that, but some of our readers (albeit a very small fraction) will be coming to this article to see how much that propagation speed difference is. We should present that info in an WP:NPOV manner. Mr. Swordfish (talk) 14:42, 4 May 2026 (UTC)

"A text search for Baird comes up empty."? Google search: christopher s baird Johnjbarton (talk) 15:05, 4 May 2026 (UTC)

A text search of the article and the talk page comes up empty. But let's move on to the more important issues. Mr. Swordfish (talk) 17:10, 4 May 2026 (UTC)

I fixed the citation. Johnjbarton (talk) 19:25, 4 May 2026 (UTC)

I pretty much agree with all of that. I want to keep, somewhere in the article, that energy and signals are conveyed in the fields external to the conductor and that is why materials external to the conductor control the velocity. I like the conduction electron velocity section, but suggest two subsections: thermal velocity and drift velocity. Then we need a signal velocity section which I presume would discuss the question of how long before energy reaches the load. I am not against showing velocity vs frequency, but if we put it in there needs to be some explanation which I think will need to involve a discussion about transients and steady state. Constant314 (talk) 19:09, 4 May 2026 (UTC)