Can someone explain live/neutral wires to me like I'm retarded? I've just realised I have absolutely no fucking idea how electrical systems work.
I went back to basics, and I understand what a volt is, what an amp is etc, but I don't understand the distinction between live and neutral wires, how a current flows to ground, or how current returns to the generators.
Help?
>>972292
live kills you.
neutral doesnt. this is the only thing you need to know. so when wiring shit up, make sure the neutral is tied to the chassis and not the live wire. same for wiring light sockets. make sure the live is the pin contact and not the ring.
>>972292
so live wire is an electrical charge from the generator/battery. a neutral wire is a wire that grounds back to the generator/battery, and if connected to the live wire there will be current flow.
if you connect a neutral wire to a ground (such as you), nothing happens, because there's not electrical imbalance. to use the water metaphor, it's like introducing a damp sponge to an empty cup.
a live wire connected to a ground, on the other hand, will transfer current until the electrical charge has reached equilibrium with the ground. so like a damp sponge exposed to a waterfall will get soaking wet.
This is why electricians working on high voltage lines wear a suit, they are insulated from the ground and the suit is charged to be in balance with the power in the lines.
So also going back to basics, the difference between DC and AC current, DC is a flow, think like a bicycle chain, AC is an oscillation, like a saw. So AC doesn't really need to complete a circuit to get power going, just to ground.
please note, that i'm an electrical idiot, and am like 4 youtube videos ahead of you in knowledge.
>>972307
>but why
Because there's no potential relative to ground on the neutral. The live swings from a positive peak to a negative peak relative to neutral/ground. You could say the live generates the voltage, the neutral just gives it somewhere to go.
You get shocked by live because, as just mentioned, neutral is deliberately tied to ground. You, being at least weakly coupled to ground, also provide a current path for the live to complete the circuit with.
Also remember that mains power is AC, not DC. You would not get a shock if it was DC because there is no unbroken conductive path from live to ground through you. However, because all things are capacitive to some degree (including you), some AC current is able to pass by repeatedly charging and discharging your body exactly as it would a purpose-made capacitor.
>>972307
Ok, so what happens when you hold a DC battery wire is the current flows into you until you hold the same electrical charge as the battery does, and then it stops. you get a shock because that's the feeling of electrical current flowing into/through you. If you held on to the wire long enough, and you were insulated enough to stop the current from flowing through you to the ground (because trying to balance electrical charge with the planet means your charge stops at basically 0), then you would become electrically charged and stop getting shocked while the battery still held power. but you would get zapped when you touched something metal and grounded yourself, from the electrical charge flowing OUT of you.
AC current, same thing, except that since the electrical charge on the wire is flipping from negative to positive, it DOESN'T stop, which is why AC current is generally considered more dangerous than DC, and also part of why it's easier to transmit over long distances.
Ok, generally water flow is the easiest analogy for how electricity works, it is not what's actually happening, but like 95% accurate for actual effects.
Live is reservoir, Neutral is Sewage Pipe, Ground is Storm Drain. hookup bucket (YOU) to sewage pipe, nothing much happens. hookup to storm drain, nothing happens. hookup to reservoir, bucket fills with water (electricity). You can cut apart the sewer lines all day and will not get wet as long as they're not connected to the main waterline.
the reason that neutral exists, is to let current flow more evenly and for longer than it takes the bucket to fill up and stop accepting water (cook and become insulated with charcoal).
and ground is so that if there is a short, it will connect to ground and go to the earth, instead of powering neutral up with the charge, and making neutral dangerous to handle.
>>972317
generally, you need a large battery and good connection to even feel it, because it tops out pretty much instantly with DC, just wanted to be thorough.
>>972307
because you are ground.
well the reason electricians use fibreglass ladders and rubber soled boots is to prevent them from grounding if they touch a live wire.
>>972298
Do not wire the neutral to chassis! Only the bond is meant to be attached there. Neutral and bond are attached in the first service disconnect, after that they are seperate
the thing at the top is an A/C generator
why do I get a shock? It's an incomplete circuit
>>972363
wrong. it's code to connect neutral to the chassis in two prong appliances. there was a time before GFCI when the fuse was the ghetto GFCI. houses didnt even have grounding rods.
>>972548
you ever hear that greek saying, "give me a lever long enough and I can move the world?"
because everything conducts electricity. given enough voltage, you can make an electrical arc approaching infinity.
>>972559
Wait, so when you get a shock from touching live, it's because you create an arc to neutral?
>>972558
>he doesnt know about the third world and that their electronics are built to expect no ground and many appliances designed for their market are sold in the international market
what do you think a ground pin does when you plug something into a generator?
>>972562
No, it's because you complete an electrical circuit. Your body becomes the electrical load and you can feel the electron pixies dance across your body at 60 cycles per second, interfering with your nervous system causing pain and muscle contractions.
>>972562
to any other potential.
live is the source of energy basically. its where the power comes from if you suspend disbelief for a moment and ignore the direction of electrons.
neutral has nearly the same potential as ground. they are connected together in the power distribution circuit. but you dont connect them together at the appliance. the ground wire is used to trip the GFCI, a safety device. if current goes to the ground wire, the GFCI shuts off the power faster than electricity can arc through your chest, causing a heart attack. this is why on three prong appliances a metal chassis is grounded. so if the live wire comes lose and touches the chassis, it shuts off the power straight away, so if you touch the conductive case of whatever it wont turn on. if the neutral wire breaks off and touches the chassis, it doesnt matter because its not dangerous and wont trip the GFCI.
anyway, due to needing to make code compatible with reality, there are provisions to allow shitty two prong devices to connect to a metal chassis. but best practice is only to connect the ground.
you get a shock because you arc to anything. hell, the EU made provisions for E-bike laws because they were worried that the electrical field around e-bike motors could kill people with pacemakers and now theres a retardedly expensive RF emissions test for ebike motors so no imports.
>every electrical device is conducting to you on some infintisimally small level.
>even some guy in china talking on his cell phone right now.
>even some ayyy lmao in a distant galaxy shitposting on alien 4chan has a current path to you right now every time he presses a key on his keyboard.
>>972591
AC doesn't require you to complete a circuit to the generator, only to a ground. You could drive a grounding rod and hook the neutral on an outlet to it, then only connect a hot wire to aforementioned outlet. Plug in your vacuum and it will work.
Correct me if I didn't explain this right guys. Yellow is approximate flow electrons.
>>972597
h-how
why do we need neutral wires then? Couldn't we just power lightbulbs off live alone?
>>972591
The neutral wire is the 0v reference for the live wire. The neutral wire is at the same potential as ground, so when you touch the live wire you complete the circuit through the ground, and die.
>>972597
>>972660
I am 90% sure that would just explode the vacuum, and hurt you. The reason being is because there is no neutral line on the vacums AC power supply once you cut the one on the outlet. Basically it would create a resistance between the vacums parts, you and ground. You need a neturel to balance the mains.
>>972668
See that's the problem you are using ground interchangeabliy and neturel isnt ground and AC appliances dont use neturel in the same way as ground. Look up how a 3 phase motor works OP, it will either make more sense or it won't.
>>972668
Also the reason ground is at the same potential as neutral is because in your home there's a grounding rod placed into the earth and connected to neutral. If you touch the live wire current flows from the live wire, through you, through the ground, and finally though the grounding rod and back into the neutral wire.
>>972660
On a million volts you could probably remove the neturel IF the power station was close enough , but would you really want that? That much energy flowing under you feet? What you should try OP is go up to a power line and cut every ground you see coming from the power line pole to the ground. Sell the copper and watch the news when everyones breaker box explodes.
>>972672
The two prong electric appliances are groubed to the case, if I remember right. That is way some things you buy 3 prongs and some have only 2
An electrical power source is something which exerts an "electromotive force" ("EMF" for short) on electrical charges, which will counteract the natural attraction of positive and negative charges.
Consider pic related. The battery's EMF will pull electrons from one wire into the + terminal and push them from the - terminal into the other wire. The wire attached to the + terminal will become positively charged, and that attached to the - terminal negatively charged.
Eventually the force exerted by the charge imbalance in one of the wires will match that exerted by the battery, and no more charge will flow.
If you were to connect more wire to the end of that wire, the battery would be able to pull more electrons from it (or push more into it) before it eventually reaches equilibrium. The attractive force depends upon the charge imbalance as a proportion of the number of free electrons rather than the absolute charge (this is why you only get a noticeable build up of static electricity with non-conductive materials like plastics: insulators have few free electrons).
To be continued ("field too long")
Cont'd from >>972679
Now suppose that you replace the battery with an AC generator. Because the EMF is continually changing direction, it will keep pulling and pushing charges to and fro, with the current determined by the EMF and the number of free electrons which could be moved.
In the case of the mains supply, one of the terminals (neutral) is connected to ground (literally, a wire connected to a metal rod driven into the ground). Thus, the neutral connection is never the limiting factor when it comes to the availability of free electrons (even though dirt is a poor conductor and has relatively few free electrons, there's just so much of it). The current flowing in the absence of a circuit is determined by the number of free electrons on the live side.
Hence, touching neutral won't give a shock, as the generator can push/pull all the electrons it wants from the earth. But touching live will allow the generator to push/pull electrons to/from your body (you're made mostly of salty water, which is a fairly good conductor).
>>972675
Anything legally sold in the EU either needs a 3-pin plug with any exposed metal connected to earth, or must be double-insulated (i.e. there must be sufficient insulation between either live or neutral and any exposed metal that contact between the two is implausible even in the event of a fault).
The case must never be connected to neutral.
>>972682
> The case must never be connected to neutral.
Not all countries even have neutral. Some have split-phase supplies (two 120V live supplies 180 degrees out of phase, the same as 240V circuits in the US).
>>972682
Well in America we do things differently.
Line and neutral are both live conductors.
You don't usually get a shock from neutral because you are usually at the same potential as neutral and so no current flows. This is because neutral is referenced to earth/ground and so are you because you are standing on it.
If you work on a building site the supply isn't referenced to earth, you have two phase conductors carrying half the voltage each. You could touch each conductor individually and not get a shock because you are providing the only earth/ground reference to the system. If you touch both or someone else touches the other you will have created a path for current to flow and you will get a shock.
Ignore anything an American tells you about grounding, they literally bury bare wires in their walls (google knob and tube) and bond neutral to earth/ground at the distribution unit rather than letting the supplier do it at the cut-out in a sensible way.
if you isolated yourself from earth/ground you shouldn't get a shock because there is no path for current to flow however it is possible if you are capacitative enough because of phase lag or some other mumbo jumbo
>>972679
Just so you know electricity DOESN'T flow from positive to negative, it's the reversal. Atoms with an abundance of electrons have a negative charge and they are attracted to atoms with a deficiency of eletrons a positive chrage. The way you are wording your response suggests that you might not be aware of that fact.
>>972674
what do you mean, energy flowing under my feet?
>>972692
Current returning to the power distribution through ground instead of neutral.
>>972686
> neutral is referenced to earth/ground and so are you
Correct.
> because you are standing on it.
Incorrect.
Anything which is electrically neutral (same number of positive and negative charges) is at ground potential.
Suppose that you have a generator with one terminal connected to ground and the other connected to a wire which goes up into space, all the way to geostationary orbit.
An astronaut who removed a glove and touched the end of the wire would get a shock comparable to if they were standing on earth on dry ground with shoes on (standing barefoot on damp ground or in a river would produce a much larger shock).
The human body (when insulated from earth and not standing close to an earth conductor) behaves roughly like a 100pF capacitor with one end connected directly to ground potential.
This is why e.g. "touch-pad" dimmers work fine even if you're wearing rubber-soled shoes and not standing near any kind of earth conductor.
>>972696
how, there's no wire down there
>>972690
Electrons flow to positive
Electricity is just an arbitrary concept, you can imagine it flowing however you like
>>972692
If you have one wire between 2 poles, a switch and a light you could you have a gold spike-because I like gold and I know it will work better. Connecting a million volts to the spike and power the light on the other pole. Using only 1 wire to connect everything! Earth ground is that special.
>>972690
Conventional current flow says that electrical current flows from high potential to low potential. Electron current flow is the opposite but for 90% of situations there's no discernible difference.
>>972700
To positive NOT from positive. Basic physics.
>>972690
> Just so you know electricity DOESN'T flow from positive to negative, it's the reversal.
1. That much is made clear if you actually read it (electrons are pulled into the positive terminal and pushed out of the negative terminal).
2. An electric current can consist of the movement of positive charges, negative charges, or both. For solid conductors, current flow is solely via movement of electrons. For liquids or gases, current flows by movement of both negatively-charged electrons and positively-charged ions.
>>972698
What's wrong with what I said?
I did mention getting a shock because you're capacitive at the end but I don't know why it makes what I said wrong.
I don't know if I can accept your definition of ground potential either. Even if its correct what use is it to anyone? Are you going to count the electrons?
>>972703
It clearly went over your head. Read it again and think about what it means before you post next time
>>972674
> On a million volts you could probably remove the neturel IF the power station was close enough
Look up "single wire earth return". It's actually quite common for supplying power to remote areas (e.g. much of Australia).
>>972702
Hey, how you design your circuit you up to you. All I know is most people forget this concept and and you see it in their work. You see twice as many connections because people don't know how to use ground. If more people understand the physics side of it, it might make people better equipped to deal with ground and use it.
>>972711
Fuck that shit, only down under would I expect that type of shit. Why not just use microwaves to power everything! Fucking crazy dude
>>972708
He's correct in saying that humans have an electrical capacitance, everything does. Your body will keep a small charge at a certain electric potential.
We do in fact count electrons, we just call them coulombs (a defined number of electrons, sorta like Avogadro's number). A volt is just how many joules of energy is contained in each coulomb. When some charge has more voltage than some other charge, charge will flow from one spot to the other, releasing the joules of difference. These released joules are what kill you
>>972707
I'll be honest I just wanted something to say.
>>972708
> What's wrong with what I said?
The "because you're standing on it" part.
You don't need to be standing on earth or even near it.
If you were to run the live wire out to the middle of deep space, someone touching the end would still get a shock.
Kirchhoff's current law (the sum of currents into any node is zero) is an approximation which is adequate for most purposes, but it's not absolute truth.
A more accurate version is that the sum of currents into any node is equal to the rate of change of net charge within that node. Objects can have a net imbalance of charge.
IOW: you don't *need* a circuit for current to flow.
>This thread
>>972722
Yep, static electricity is current without a circuit. Electricity doesn't care if there's a way back, it cares about the energy that charges have (Voltage)
>>972722
but you are at ground potential because you are standing on it. if you were insulated or floating is space you could pick up charge from your nylon spacesuit or the balloons used to get you up there rubbing together.
being grounded ensures you are at ground potential.
i didn't say you would only get a shock of you are grounded.
>>972292
>>972307
>>972548
>>972562
>>972591
>>972597
it's this >>972597 and this >>972674
They call it "ground" or "earth" for a reason. If you're outside or connecting to a properly grounded line, the electricity literally goes into the ground and disperses into the dirt, traveling outward until it's too weak to go anywhere (which is not far because dirt isn't a great conductor). In your house the same thing happens with your floor. It happens because large things that don't have a power supply connected to them typically don't have much charge (or electrical potential) to them. This is also why it's recommended to not swim during a thunderstorm, the power from the lightning can travel through a surprising amount of water before it's dissipated enough to not hurt you.
>>972699
Dirt isn't a great conductor but it's more conductive than plastic and a lot of other things, and it doesn't really matter anyway, with enough power the electricity will push through. I was under the impression it wouldn't get all the way back to the power plant in any meaningful degree through the ground, but I haven't read up on these single-wire systems someone mentioned.
>>972597
so why doesnt this give me a shock?
>>972868
The circuit as drawn would give you a shock.
You forgot to show the earth connector, which means that you're competing with the planet (which is a bit larger than you) for those electrons.
See the three circuits in the attached pic. Assume that the voltage between A and B is 120V in each case.
In the topmost circuit, touching A would give you a 120V shock, touching B would do nothing. In the middle circuit, touching A or B would give you a 60V shock. In the bottom circuit, touching A would do nothing while touching B would give you a 120V shock.
>>972548
Think of earth as a storage of all kinds of charges. So if you are touching something charged (A live wire) and at the same time being grounded (providing an easy acess to the storage) current will flow through you and you will get shocked.
>>972597
>>972868
neither would give you a shock
the bottom transformer is isolating, the only reference to ground is you.
both lines are floating, at in theory half the voltage each. touching one will drive the other to full voltage but no current will flow and you won't get a shock.
in reality, in the final loop, one side is connected to ground, that is the neutral. draw it in and you will see the loop.
>>972722
>someone touching the end would still get a shock.
birds sit on power lines all the time and they aren't even in space.
>>972900
Because once they land on the wire, they have the same potential as the wire. If they were some huge mythical bird and put their legs on two wires, or touched the wire and that one wire on top, which is the ground/earth wire, they'd fry.
Or if you went up in a cherry picker, touched the bird on the wire, you and the bird would fry.
If you climbed up the pole with the proper safety equipment, and touched the bird, nothing would happen because you and the bird and the wire have the same potential. Electrically speaking, you'll never fly and know true freedom like the bird can.
>>972904
i was replying to anon saying a spaceman floating around in a vacuum would experience a shock. so unless they send up astronauts with a ground wire running back to houston....
>>972894
That's actually wrong, although if you don't understand why by this point, you probably won't understand without actually trying it. If you are planning on trying it (i.e. touching one terminal of the secondary of an isolating transformer), you need something with sufficient self-capacitance on the other terminal. 6 ft of metal pipe should do.
>>972900
> birds sit on power lines all the time and they aren't even in space.
Most residential power lines are insulated. Also, birds have much lower self-capacitance than people (self-capacitance is proportional to size; roughly 50pF per metre), so much lower current.
>>972907
Try it. Run a live wire to the top of a tall plastic step ladder (so you're nowhere near any external ground), wear rubber-soled shoes, and touch the end of the wire.
>>972930
> Try it
While you will draw current, it will be far less than if you're standing near the ground (or other mass with significant capacitance).
The self-capacitance of the human body is ~100pF, which equates to ~25 megohms at 60Hz. At 120V, that's going to result in ~5uA, which isn't even noticeable.
Unless you're standing at the top of an insulated ladder (and outdoors), capacitative coupling to earth will result in significantly more than that.
>>972930
Try it. Run a live wire to the top of a tall plastic step ladder (so you're nowhere near any external ground), wear rubber-soled shoes, and touch the end of the wire.
Funny story, One day I was using this old, shitty metal-chassis electric drill up on a plastic ladder. I depressed the trigger to put a hole to run some conduit through and.... I could'nt stop depressing it! It didn't whir or drill anything, but it apparently had a loose wire that shorted it through the metal body, ran the current through me and back through the 'safety' ground plug on the extension cord. I was paralyzed and in intense pain and I pretty sure I was going to die but then gravity leaned me over, tipped myself and the ladder the opposite direction and the drill came unplugged from the extension cord.
Never been so happy to fall off a ladder! I also never buy metal-chassis power tools anymore either.
Thats not the same thing as what you said but I thought the story is fun enough to share.
>>972943
This story is also how most people (well, tradesmen and labors) are actually killed by an electrical fault. Get shocked, fall off the ladder and shatter your skull. get shocked, fall off the ladder and hang yourself on the wires you were feeding, etc.
>>972307
you become the filament (the thing that gets hot and makes light) in the light bulb
>>972948
> Get shocked, fall off the ladder and shatter your skull. get shocked
Indeed. You're highly unlikely to get electrocuted from 240V (even less so from 120V).
>>972930
>Most residential power lines are insulated.
Where the hell do you live? The only insulated lines in the US are communication lines and once they leave the pole. Voltage on power lines in the US is ~13500 VAC and it gets stepped down either on the pole or in a transformer on the ground depending on the distribution, utility, etc.
PEOPLE CAN SIT ON POWER LINES TOO
https://www.youtube.com/watch?v=6_NEAEGeFIw
Volts/grounding/socketa/water analogies/nigger analogies...
>>973002
But amps kill!
>>972299
DC to ground can also kill you. You just dont see DC over 24 volts very often.
I know someone is going to make the retarded remark "its amps that kill you not voltage!!"
No shit, however it takes at least 50 volts to overcome skin resistance and flow through your body. You could touch 24 volts with a 5 million amp power supply behind it and you wouldnt even feel it.
>>972660
No. Generally everything attached to electrical devices is insulated to prevent voltage from going where it shouldnt. You could replace the neutral with a wire going to ground, and it would work but, its less efficient, its dangerous, and its more difficult to get an exact voltage that way (since voltage is a measurement of DIFFERENCE in electrical potential energy, you could take a voltage reading between an outlet in your house to ground and get something other than 120/240 volts if the ground had a charge).
So spent 9000 hours in paint, am I understanding it correctly? Also, what would the third wire in some plugs be doing?
>>973002
>nigger analogies
Am i a meme now? Noice.
