how does electrity flow in wire

Just wondering how does electricity travel in wires. 1. Is it molecue to molecue 2. On outside surface of wire 3. Other Can multiple strand wire carry more electrity than solid wire?

The electrons are attracted to the protons . For stranded vs solid the theory is "skin effect". Just google any of this and you can read theory for days.

Electric current is movement of electrons through a conductor. The electrons move from the orbit of one atom to the next, hopping their way along the conductor. Because metals easily share electrons, they make good conductors, while non-metals don't tend share electrons and therefore make poor conductors.

For direct current, the current is spread evenly across the cross section of the conductor. Alternating current tends to move closer to the surface of the conductor. This "skin effect" is small but measurable with 60 Hz power; it becomes very significant at higher frequencies.

For all intents and purposes, there is no difference in the current capacity of stranded versus unstranded wire.

I"m sure someone can give you a more thorough answer but I think it would be atom to atom. Copper is an element with 1 electron in the outer orbit which is allowed to move easily between atoms. As to which carries more, I think it is a function of cross-sectional diameter. Solid would seem more efficient but I don"t know for sure.

Electricity is smoke that is pumped in one end of the wire and it comes out the other end and back to the power station where the smoke goes up the chimmney. If the smoke comes out of any device, it means it's bad.

Comon' now,

You don't really think anything 'moves/transfers/travels' do you?

Allan

At modest voltages (less than 500) the electrons, that are electricity as they move, travel from atom to atom. They are a negative charge. The conductor (metal for simple example) when in the solid state (wire) has atoms that are close enough together that their outer clouds of electrons mingle rather freely. Kind of like musical chairs with 20 chairs and 30 people. The freedom to move makes it easy to push them around with either magnetism, or chemistry. Imagine a hose full of buckshot with water in it. The buck shot is atoms and the water is free electrons.
The water can flow through the spaces. When we ad water to one end, water is forced out the other end (near immediately, speed of light).
Current is measured in Amps. 6.24X10 to the 18power electrons passing one point in one second is one amp. One volt pushes one amp through one ohm. Jim

In a good conductor such as say copper, there are plenty of available free electrones orbiting in outer shells just sittin there waitin to be knocked out of orbit and moved to the orbit of the next atom. Such a flow of electrons is called current and is measured in coulombs per second.

So to answer your question, electrons flow from the shell of one atom to another provided the atoms have readily available free electrons ready to be moved and pushed around. If none such exist and theres no free electrons its a poor conductor such as say glass or plastic etc

Now, (This blows some peoples minds) electrons are NEGATIVLEY charged particles and while they flow in one direction (from a lower to a higher charge state, - to +, similar to Opposites attract, Likes repel), the empty spaces or holes left behind necessarily flow in the opposite direction. Thus theres electron current and theres hole current. Electrons flow one way and the holes left behind cuz an electron was knocked out of its orbit flow the opposite way.

At Purdue University in the sixties we called it CONVENTIONAL CURRENT which flowed from the + of the battery towards the - while at the same time in order for that to happen ELECTRON CURRENT '''''''INSIDE '''''''' THE BATTERY HAD TO FLOW FROM - TO +. That made perfect sense as far as electrons and "electron current" is considered inside the battery because an electron, being a NEGATIVELY charged particle, would naturally flow away from the LIKE - post towards the OPPOSITE + post.

And then theres the whole field theory and quantum mechanics and Maxwells Equations stuff which really blew even an engineers mind lol so Im stopping with the above which I hope helps you NOTE This was over 40 years when I learned all this and Ive slept since SO NO WARRANTY LOL

As far as current flow on the outer versus inner surfaces of wire.........Youre thinking of whats called the "skin affect" but thats only relevant AT HIGH FREQUENCY NOT DC so at DC in a cross section of wire current flow would be the same. As far as stranded versus solid, if theres no HF skin affect going on the net cross sectional area is all that mattersd, if theres more = more current capacity REGARDLESS if the sum of a big fat wire or a bunch of small stranded wires CROSS SECTIONAL AREA

HOWEVER multi strand wire is much more flex resistance and pliable and Id sure want it for welding cable then big fat single wire wouldnt you?? But regardless then net sum corss sectional area being more means more current

Anyway thats the best I recall from Purdues Electrical Engineering profeessors wayyyyyyyyyy back in the sixties, maybe physics has changed since then????????????

John T BSEE but that was a longggggggg timeeeeeeee agoooooooooo lol

Another interesting question...do the electrons flow from + to - or the other way around?

By the way - the early physicists got it wrong...

An electron, being a negatively charged particle, would flow from a lower to a higher charge state, i.e. away from the LIKE - towards the OPPOSITE +, see my detailed explanation below.......

John T

Around the outside surface of the conductor and Yes a stranded conductor can carry more amps with less heat because it has more outside surface than a solid conductor.
Later Bob

At high frequency a phenomenon called the "skin affect" causes the majority of electron flow to occur along the outer perimeter of a conductor but no so at DC

Hope this helps,

John T

My city cousin peed on a electric fence, he moved in a hurry.

current tends to travel along the outer surfaces of a conductor in a process known as skin effects. in large electric substations the high voltage buss work is sometimes hollow tubular bars so designed for that reason. electric transmission lines are made up of stranded aluminium conductors wrapped around a steel core. steel core for strength and wrapped stranded conductors for ampacity. large solid conductors imparts more resistance in the circuit, this combined with skin effects tends to restrict current flow. stranded conductors typically will have a higher ampacity due to their smaller individual size having less resistance and also each strand will have its own skin effect. there is some thoughts that stranded conductors have less heat dissipation which will serve to reduce current flow.
now is it atom to atom or does each atom just bump into each successive atom to make current flow?

The whole study of the process is called Quantum Mechanics and it deals with the electron levels in the various shells of the electrons surrounding the atom.Each shell can hold a finite number of electrons and they can move from one to the other--mostly in the outer shells. If i remember right the first 4 shells were called S,P,D, and F and yes the move more rapidly on the surface of a wire

Yup. It just seems counter-intuitive that electricity flows from ground to positive. Seems like it should flow downhill (so to speak).

Fer sure, Plumbers say all ya gotta know is $$it flows downhill lol

John T

Magic

Just to add, as frequency increases so does the skin effect.......Of course pure DC is pretty dern lowwwwwwwwww frequency lol not a problem

John T

mult strands will cary more amps that why your leads from your battery are stranded and not solid

not magic; just electrical, mechanical and civil engineering utilizing the natural flow of electrons from a magnet-from the negative pole though the atmosphere to the positive pole.

Now if current can make a needle move on an amp meter something is moving somewhere

Ah but does power flow or is it the bump effect?? Then with DC is it different then AC as in in DC is it flow and AC bump??? I was taught both ways and when I was taught it was still theory and was said no one really knew for sure if it flowed like water or if it was more like a multi car pile up on a hwy

Tie a knot in the wire and see what happens!
Sam

...and friday is payday!!

Electricity is similar and related to Chemistry as all the action really takes place with the electrons and their orbits. Nothing changes in the nucleus.
Anion is negative with an extra electron.
Cation is positive with orbit that has a hole attracting an electron.
That's pretty much a thumbnail sketch of batteries, acid, alkaline, electricity, vacuum tubes, solid state electronics and even molecular chains in biology.
On the other extreme. Messing with an atom's core protons and neutrons by splitting them apart like U233,U235 or P239/P241. Also crushing atoms together like H2 or H3 can make for a very loud and bright Ka-Boom.
Thorium 232 naturally breaking down into radon 220 and collecting in your basement is a bad news carcinogen.
Of interest however is that Beta radiation is a hyper annoyed electron that has been booted at extreme speed out of a splitting atom's orbit.

Wrong answer-The real reason batt. chargers or any cord that is used often or subject to vibration is multi strand instead of solid is durabilty-it will bend a lot more times.

Not quite. $hit goes down and stink goes up!

"...the natural flow of electrons from a magnet-from the negative pole though the atmosphere to the positive pole."

No. There is no "flow" of electrons between the poles of a magnet. For electrons to move, they need an electric potential (measured in volts), and there's no such electric potential in a magnet ("Normally", I should say, since one COULD create an electric potential in a magnet by running current through it.) Magnets create MAGNETIC fields; magnetic and electric fields are quite different things.

i did use the wrong word. voltage is produced whenever a conductor is passed through a magnetic field, electrons flow when a load is connected to that conductor. thanks.

I was trying to explain how power travels in the system of a generator and transfer switch. An old man customer told me. Don't care how it gets here as long as it gets here.

And never lick your fingers!

I am thinking skin effect does not apply to DC, so the total area of the conductors is what carries current, not circumferences of individual conductors.

If you tie a knot in the wire,don't you see the smoke can't get passed it,,,,,at least I don't think it can.
?????? George,,,what happens if you tie a knot?

John T. this is what we were taught in school too!

all this info is well & good---but i'm still sittin' here waitin' fer a jump-start----

used to know an old time electrician that was his own tester , he would hold 2 ends of wire and his helper would flip the breaker ,kinda reckless ,but his last child was born when he was 60yrs old ,LOL ,.. the old fella would holler out as soon as he felt a trikle ,and his helper would throw the switch ........,electric travels at somewhere between the speed of lite and sound .. when in a strain it does not wiggle and gallop the powerline wires like a flat belt on a chuugiin thresher and steamer ...

NOPE, see my detailed explanation below. at DC there IS NO SKIN EFFECT what matters is the net sum cross sectional area, the more cross section the more flow regardless if theres small wires or big wires. Stranded is used for welding cable due to superior flexibility and vibration resistance NOT to carry more current. Similar battery cables need to be stranded to withstand flex and vibration so as not to stress and break the wire, the current rating depends on the net sum of all the cross sections

NOW if we were talking high frequency your thinking comes into play but NOT at DC

Hope this helps yall, best wishes n God Bless

John T BSEE Electrical Engineer

Youre thinking exactyl right NO DC skin effect, ther more cross sectional area the more current capacity, small strands are for vibration and stress resistance and flexibility NOT for more current UNLIKE HIGH FREQUENCY where skin effect is indeed present

John T BSEE Electrical Engineer

(quoted from post at 23:32:38 02/18/13) used to know an old time electrician that was his own tester , he would hold 2 ends of wire and his helper would flip the breaker ,kinda reckless ,but his last child was born when he was 60yrs old ,LOL ,.. the old fella would holler out as soon as he felt a trikle ,and his helper would throw the switch ........,electric travels at somewhere between the speed of lite and sound .. when in a strain it does not wiggle and gallop the powerline wires like a flat belt on a chuugiin thresher and steamer ...

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Hmmm , do you think it might work when a feller is turning 85? :shock:
Where/how did he hold the wires? :?

Passing a coil of wire past a magnet or pass a magnet by it theres a voltage induced across the coil ends,,,,,,,Pass current through a wire theres a magnetic field produced,,,,,But no electron flow through a magnetic field, just the electrical conductors provided a source and load and a circuit

Hope this helps

John T

Tie a knot in a wire and put a few bends in a wire, maybe you could confuse the electricity. LOL

Hi, don"t post here very often, but as a practicing EE specializing in electromagnetics and having almost 40 years experience, I have an overwhelming urge to correct some of the misconceptions and patent nonsense I see in some of the answers here.

First, in answer to the original question, electrical current is the movement of charge carriers. In metallic conductors, the charge carriers are electrons; in some other materials, such as the electrolyte in some battery chemistry and some semiconductor materials, the charge carriers are actually positive ions. 1 ampere is defined as the movement of one coulomb of charge per second - there is nothing in this definition that says what the polarity of the charge carriers is.

An yes, Ben Franklin got it wrong. In a metallic conductor, the actual charge carriers move from negative to positive, however, from a practical standpoint it really makes absolutely no difference unless you"re working at a molecular level. The term "conventional current" is often used for the assumption that current moves from positive to negative.

In a good conductor, such as a metal, the outermost electrons are very loosely bound to the individual atoms. If I shove an electron into a conductor, it will displace an electron from one of the atoms. That electron will in turn displace an electron from another atom, etc., etc., etc. Insulators are insulators because the electrons are very tightly bound to their atoms, and it takes a LOT of force (voltage) to break them loose. There are some other mechanisms by which electrons move through materials, but these can be ignored unless you"re worried about things like how high energy electrons interact with materials in a spacecraft, or the physics of an arc, or other rather esoteric effects.

Here"s a relatively simple analogy for current flow in a wire. Think of a long tube filled with a fluid...if I force a small amount of fluid into one end, it will push a corresponding amount of fluid out the other end, even though the individual molecules haven"t moved very far. An analogous thing happens in a conductor...if I shove electrons into one end, a corresponding number will be forced out the other end, even thought the individual electron that I forced into one end is not the same electron that came out the other. This is how electrical signals move along wires at something approaching the speed of light, even though individual electrons only move along the wire (as I recall) at a few inches a second.

At DC, the current will distribute evenly through a conductor..."skin depth" at DC is infinite. At 60 Hz, unless you"re working with conductor dimensions measured in inches or 10"s of inches, it"s also safe to assume that current distributes evenly throughout the conductor. For the size conductors that most of us are concerned about, "Skin depth" is only a concern for things like RF transmission lines, which carry energy at much higher frequencies.

Stranded wire is used for mechanical purposes, not electrical. Fine strands are able to flex without breaking or work hardening in a vibration environment. For a given amount of copper, a single solid conductor can carry exactly the same amount of current as the same amount of copper made into a number of fine strands. Note that a stranded wire may be bigger in diameter than an equivalent solid wire because of the air spaces between the individual strands. There are also some minor thermal differences between stranded and solid conductors as a result of the way heat moves through the conductors.

There"s also an interaction between electrons and a magnetic field. An electron moving through a magnetic field experiences a force; conversely, a moving electron (as a result of an applied force) creates a magnetic field. This relationship between current and magnetic fields is the basis for all elecro-mechanical devices, such as motors and generators. For example, moving a wire through a magnetic field results in enough force on the loosely bound electrons to cause a current flow in the wire...note that this can be either a stationary wire in a changing magnetic field (such as in a transformer) or a moving wire in a stationary magnetic field, such as in a generator.

Hope this helps a little,

Keith

Being your own tester works only if yer leg bone connects to yer knee bone, then if yer knee bone connects to yer thigh bone, then yer thigh bone......

Excellent description.

Thank you to all the super explainations? It always amazes me with all the experts who are willing to share their knowledge so that we all can grow in intelligence.

Why when a conductor heats up and the electrons become more active does the resistance on the wire increase? It seems that the resistance would decrease with temperature and the electrons would flow easier.

Just a minute and I will help you get your tractor started. But now I need to sweep up all of this electricity that spilled on the floor overnight. Boss wants to save the protons and throw away the electrons, or is it the other way around?

Sure glad I didn't get involved in this. Some AMAZING stuff stated herein.

Mark

I will be right over. As soon as I get the smoke back in the wires.

Think of electricity as water flow or air flow in a pipe or air hose and a pressure tank as a battery or storage vessel.

Voltage is the pressure of the water or air.
Current is the flow rate of the water or air.


More voltage or pressure means that you need a thicker air line or water line to hold the pressure.

More pressure or voltage means that you can also get more work done with the same size hose or air line.
ie a 1 inch garden hose will wash away more leaves or dirt at 100 lbs than it will at 5 lbs. So more voltage or pressure will push out more than less pressure will.

Conversly a bigger pipe or air line can do a lot more work than a small line with the same voltage or pressure. IE a fire hose at 50 lbs will wash off more leaves off the side walk than a garden hose at 50 lbs.. So more current will do more work at the same pressure than less current at a given pressure.

So, now you know how voltage and current works and why you need a bigger conductor/pipe for more flow.

While its been too many years since I studied skin effect... I do remember that under high current flow and high voltage.. Electrons are repelled from other electrons and are attracted to protons. So.. If you have lots of electrons, they tend to evenly space themselves as far away from each other as possible in the conductor.. As voltage increases,and more electrons are force into the conductor they will start to move to the outer edges of the conductor as there are no opposing electrons outside the conductor and lot inside so the electrons will move from the center to the outer and flow more there. With more electrons now flowing on the outer surface area, a stranded conductor can actually have more outer surface area due to the multistrands than a perfect circle. So in thery, more surface area will carry more current in certain conditions, and stranded will provide more outer surface. So there Lies the basis that stranded will carry more current in high current situations than solid. And stranded tend to run cooler at the same level due to the ability to pass more current in these situations.


Can I back this up? Will have to go back to my old engineering books. Its been 40 years plus. But this will hopefull help understand voltage, current and skin effect.

RF engineering and coax vrs waveguides are a bit difference based on frequencies.

What is in a magnetic field is electricity to begin with. You harvest it by passing a wire through the field. You don't pick oranges from an apple tree.

Used to when alone stick 2 wires together to trip breaker and save time. Bout 20 years back, did this and could not get breaker to trip.

The wires stuck together and the lights started to go dim. Finally cut them and went to the panel and found wires with no breaker attached securely to buss bars. Asked for assistant after that. Dave

Magnetism is a nuclear force, somewhat related to gravity.
Electricty is just moving electrons.
About as related a compound bow is to an arrow.

(quoted from post at 21:00:44 02/18/13) Electricity is smoke that is pumped in one end of the wire and it comes out the other end and back to the power station where the smoke goes up the chimmney. If the smoke comes out of any device, it means it's bad.

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Excellent!

(quoted from post at 22:37:40 02/18/13) Wrong answer-The real reason batt. chargers or any cord that is used often or subject to vibration is multi strand instead of solid is durabilty-it will bend a lot more times.

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I believe this to be true.

Add convenience to this as well.