/diy/, how is ac mains polarized??? i mean, i just don't get the concept... the polarity changes like 60 times in a second, what's the point of having a hot and a neutral wire, and how are polarized sockets (like bulb sockets) any safer than anything else? i don't
pic relativity unknown...
>>961664
>the polarity changes like 60 times in a second
120 times for 60 cycles per second
>what's the point of having a hot and a neutral wire
The electrons have to go/come from somewhere.
>how are polarized sockets (like bulb sockets) any safer than anything else
Outside is grounded (no charge), inside is electrified and will shock you.
> i don't
I should always be capitalized
>>961670
>>what's the point of having a hot and a neutral wire
>The electrons have to go/come from somewhere.
but they go both ways in both wires, what's the point in marking any wire differently?
I still don't
(better?)
>>961664
neutral is bonded to earth so there's no volts to zap you there.
then if you make sure your switches are on the hot side (ie. with a polarised socket) you can fingerfuck a switched-off device with no fear of electrification.
>>961675
i find this strange, because its not like this here in Europe.
here ground is not connected to either phase, but in between them.
if there is a short from either phase to ground the fuse will trip.
an earthfault indicator will also trip if you have one.
I'm not saying this is a better system, i honestly dont know.
>>961681
OP here, also eurofag.
so is there any difference in hot and neutral in euroland?
>>961685
AC is exactly the same as DC except the voltage switches to negative 50/60 times per second.
>>961664
Polarized is kind of misleading in the sense that there is no positive and negative per se, but there are hot and neutral, signal and ground, as it were.
They use "polarized" plugs because a lot of manufacturers use the metal housing of the device as the ground. It's convenient, but imagine if you sent the 120v AC signal through that side, the device would work fine, since it's AC, but the chassis would be live! Might not seem like a big deal, until you realize you are touching a metal desk with your other hand, so the moment you touch the chassis the easiest path to ground is through your body and not the device.
>>961681
>>961685
At least in Switzerland, 20 years ago it was common to see 240 circuits branched off of 380v 3phase, using one of the 3 hot wires (phases) and ground. Older 3phase circuits usually just had ground and no neutral. Older 3 phase plugs were 4 conductor, the 3 phases and ground.
Later 5 conductor wiring/plugs were brought in, but it was common to just tie the ground and neutral together since at the wall there was no neutral still.
If you plug a machine wired like that into a modern circuit you pop the breaker as it see current on the ground.
So- 3 phases, each 120 degrees out of phase, each showing 240v to neutral, all together giving 380 once you do the math with the phasing.
In the U.S., and I guess Euro, neutral is tied to ground at the panel, after the breakers/fuses.
Back to the OP- in U.S. 120v and Euro 240v, there's one hot and one neutral (plus ground). In some applications with grounded chassis, if the hot wire were to get mixed up with neutral you could have a live chassis.
240v in the U.S. uses two hots, out of phase. Here, as above, you can take either hot and pair it with neutral to get 120v.
>>961672
>but they go both ways in both wires,
They don't though. The hot wire is the incoming electricity from the utility. The neutral is tied to your ground at the breaker panel (or fuse box, if you are still using something that old). While the polarity changes the electricity still 'flows' from hot to neutral.
>>961690
Sounds like someone got drunk and copied the American system (which was developed by a bunch of drunks) but sobered up a bit before finishing the design. Out here we supply 240v to the breaker but it is 2 phase. So two 120v phases. Each house gets two lines, each at 120v. One line feeds half the breaker and the other line the other half of the breaker. If we need 240v for a stove or AC or something we put in a double breaker that uses both phases and send it to an outlet that uses a 4 prong plug (hot #1, hot #2, neural and ground). Older outlets used 3 prongs and omitted the ground. Madness, I know.
>>961687
>what is reactance
>what is RMS voltage.
>ac synchronous motors
>real power vs apparent power
thanks genius.
>>961697
what the fuck america
>>961687
You don't know what you talking about nigger
>>961681
Of course it is !
In Europe, neutral is connected to earth at the electricity producer, of course not at your home !
Neutral is only the voltage reference (Voltage is a potential difference, so you always need two voltages), the current flow (comes in or out 50/60 times per second) from the "hot" point (the phase). In high power multiphases system (triphasé in France) neutral is not compulsory.
OP here, I'm starting to realize my lack of understanding is very much based on the fact that I'm a eurofag and except for industrial 3-phase sockets, all our plugs are non-polarised (at least here where I'm at...).
Not really on topic, but coming from U.S. I always liked that almost every place in Switzerland has 3 phase, even the tiniest apartment I've lived in.
The Swiss being Swiss make it easy for those 3 phase outlets to be useful even if you don't need 380v.
The pic is a 3ph socket with 3ph plug on left and normal 240v single on right. You can see that the 240 will plug right into the 3ph, grabbing one of the phases and neutral.
>>961697
>two phases
Not even close
Your house is electrified by one of three 240v phases coming from the transformer. Depending on how the grid is set up in your area the neighbors in the houses across the street may be in a different phase than yours.
That 240v line is is a full sinusoidal wave that comes into a coil in the meter. The mating coil has two pulls on the ends and a center pull. This center pull is where your neutral comes to inside the house. The two pulls on the end of the coil lead off to your hot leads in the breaker. The breakers connect to the hot lead and the center tap producing 120v differential. Another breaker will connect to the other pull and the center making another 120v that is 180 degrees out of phase from the other.
If you have a 240 outlet in the garage then this breaker will skip over the center pull and connect to the full 240volt pulls.
This setup is what allows GFCI circuits to work. If there's a current imbalance between ground and neutral (of which neutral is referenced to ground) the circuit will cut off the hot lead stopping the evil wall pixies from hurting you.
>>961722
You mean if there is current flowing from hot to ground. This is how the ground and neutral being bonded at the fuse panel works. Hot to neutral is normal. Hot to ground is bad. Of course old appliances had just normal fuses and no ground fault protection. Metal chassis with just two prong plugs have a crude fire prevention system where if it shorts to the chasis, which is bonded to neutral, the power goes out. If you fuck up the hot and neutral points, if you just are connecting the power to something with no external metal parts then everything will be fine. If you fuck up with an old or dodgy 2 prong device, you will be making a shiny live box appear in your house.
>>961722
HVAC faggot GTFO. You are an idiot giving misinformation still.
The only coil in your meter is the motor that turns the disc in the meter. There isn't a 500 amp 240v transformer hiding in that little box.
You are so full of shit jesus Christ. Walk outside your house, look at a fucking wire coming off the pole
There is a shiny metal wire. That's neutral. There is two black wires. Those are the two different phases coming right off the pig. This is how it is in virtually all US residential installs.
The only time you're going to have a transformer on site is large commercial or large apartment buildings, and then it's not going to be 240v, because what the fuck is the point of running a 5000 amp 240v circuit for a 10 unit building? I don't think there's a provision for running a fucking 3/4"x8" bus bar as a service drop.
Many residential neighborhoods don't even have three high voltage phases available because it wasn't necessary. I have seen lots of customers pissed off it is going to cost them $50k+ to get three phase to the meter of their metal shop because there's no third phase for a mile.
>>961722
>>962156
This man is correct
engineer here, >>961722 is correct about how power is delivered to homes in the united states
>And then there are the south Americans
>>961705
That's pretty nifty
>>962192
What the actual fuck?
>>962238
Electric Heated Shower Head.
Yes, they do occasionally kill people from electric shock.
>>962192
>>962238
>>962256
http://johnnyvagabond.com/travel-tips/survive-suicide-shower/
http://www.theexpeditioner.com/travel-tips/the-frightening-case-of-the-homicidal-shower-head/
Is real.
>>962260
High setting is normally 5kw or higher. But, they last as long as 30 seconds to less than 1 year. They always sparks and explode.
>>962260
>I can't imagine they'd get the water more than luke warm with any decent flow rate...
I have 2 in my house.
They can easily scold you. If you don't have a high flow rate. I can't exactly tell you the rate as I have not measured it but I have to have mine with enough flow rate to easily blast you out the shower.
>>962286
I have had my old one for over 3 years. When you go to a hotel in the west indies and they are not solar heated water they will all be electrically heated at the head.
We don't know what this "normal" boiler room shit is because we don't have no central heating.
>>962286
>>961664
the way I understand it:
imagine you have a sin wave that goes between 5v and -5v. This would be "live"
the "neutral" would be 0v, or "ground," not to be confused with "earth"
>>962302
>We don't know what this "normal" boiler room shit is because we don't have no central heating.
But like typical huehue's you nigger rigged it instead of putting the slightest bit of thought into it.
>In Asia, I found similar setups, but there the heater is a sealed, waterproof unit mounted on the wall and I never really worried about being shocked.
That's a sensible, normal, safe way to do it. But that wouldn't be the huehue way, would it?
>>961700
Shit nigga lrn2EUelectricity. Any TN-S or TN-C grid system has the "ground" lead actually connected to the fucking ground at least at the breakerbox at the side of your mudhut. It should also be connected to any lightning protection system installed, which, again, is as if by miracle, connected via the shortest path directly to ground. The ground being the actual fucking earth you walk on.
>>961722
>>962326
>sealed water proof unit.
The guys who write
these articles really have no idea.
Before I replaced mine with HUEHUE heaters I had 4 washrooms kitted out with English bought wall mounted units and they are definitely not sealed. I still have one in my house right now.
The only difference is that there is a case to hide all the connections but the cases are generally not waterproof.
>>962257
Jesus Christ. I don't know why white supermacists talk about anything but that and how Koreans think a fan can kill you.
>>962399
>but the cases are generally not waterproof.
The heating coil, valves & electrics of the unit are all separate, water tight & insulated. Of course the actual outer-case comes off; you have to connect it up to the water & electric supplies somehow.
It's sure as shit a better design that the wire-the-shower-head-to-the-ungrounded-water-pipe-hue-hue-hue method.
>>962339
True, but TNS and TNC are not used by "consumers". So in residential houses, you have a single phase, a neutral, and the earth is physically grounded. On the BT transformer, yep the neutral is connected to earth, but certainly not at your fuse or braeker box ! (photo or it does not exist !)
>>962405
Stop channeling HVAC faggot
Here's a box. If it's the main panel you swing that screw over and shove it in the neutral bar. If it's a sub panel you don't.
>>962405
>yep the neutral is connected to earth, but certainly not at your fuse or braeker box ! (photo or it does not exist !)
Are you in the U.S.?
Neutral is always connected to ground at the main breaker box of the building, and only at this point.
My house has two phases at the breaker box and a grounding bus bar. Hot wires are either phase. Neutral and Ground wires are both hooked to the same grounding bus bar. The grounding bus bar is connected via bare 4AWG wire to six 8 feet long, copper jacketed steel rods in the ground outside the meter.
The ground wire in appliances is strictly for short circuits.
Uk here, king of electricity (bs1363 anyone? 240v anyone?)
our regulations require isolation of all live conductors (line and neutral) for an installation at a single point. typically this is the incomer at the consumer unit or possibly a dual pole isolator after the meter.
to bond the neutral and earth in the consumer unit would leave the earth floating when the neutral was isolated.
bonding at the cutout where the dno fuse lives solves this problem.
>>962403
Here is my Gainsborough 720 exterior
>>962403
Here is my Gainsborough 720 interior
UK bought water heater
>>962403
Here is my super ducha quattro exterior.
It is all clamped together so to open it up I might kill it. But there is a ground wire and I haven't been electrocuted in 3 years of use. And 8 years on a similar unit before.
These places that have electrocution hazards tend to have bad electricians. I had computer monitors and fridges discharge through me through their housings and I even have a plastic socket that was shocking before I re did the electrical in my house.
Ground leaks are bad no matter what you are using.
>>962446
Forgot pic.
(I'm only vaguely knowledgeable about average UK household wiring, don't take this as definite fact)
The whole 'live and neutral' thing comes from the fact that neutral is connected to ground (either at your house, the substation or both). Ground is physically connected to the earth, so (don't try this, if you've got bad wiring it could mess you up), if you stand in a muddy puddle, and touch a ground terminal, there is absolutely no voltage across you. Since neutral is connected to ground, you could touch a neutral terminal, and be safe too. However, if you touch a live wire, you'll get shocked.
I think the reason between separate ground and neutral connectors is that in a perfect situation, no current should ever flow through the ground connector. The people that make things like your metal toaster will connect the metal part to ground, so if a live wire comes into contact with it, it'll short out (and trip, and switch off the mains) - this is better than you touching the toaster, only to learn it's live. If the neutral wire comes into contact with the toaster body then any current which would normally be returning through the neutral wire would be split through the ground wire too. If the current going out of live does not equal the current coming into neutral, then there must be a current flowing along ground, this indicates a fault, and your power will trip.
>>962423
Pretty much this except we are single phase 220v at 50hz for a regular residential house and our ground wires are always coated.
>>962438
I really hate your country.
But I cannot fault your electrical standards, yard tools like spear and jackson, English mustard and old rosie cider.
>>962447
>dat perfect angle on the electrical wire that allows water hitting it to go right into the connection box
>>962452
This is correct, and applies to any system using a neutral+ground, not just UK mains.
>>962452
>this indicates a fault, and your power will trip.
Where I live, you have to install a special GPF breaker for that. They are only required around areas that have water like kitchen sink and bathroom. Everything burns up shit until the breaker flips, but the breaker doesn't always flip.
I actually had a fire under my house because someone didn't put up a wire. It was laying on the ground, mice chewed it, and it shorted. It turned into a toaster wire. Luckily, nothing bad happened and I caught it in time. Had I not been home to smell it through the heating ducts, I wouldn't have a home.
>>962403
>The heating coil, valves & electrics of the unit are all separate, water tight & insulated. Of course the actual outer-case comes off; you have to connect it up to the water & electric supplies somehow.
Ha ha, o blissfully ignorant...
https://www.youtube.com/watch?v=cNjA0aee07k
>>962475
> Everything ELSE burns
fixed, left that out for some reason
>>962472
I know. I know. But by the grace of god nothing has gone into the conduit box yet.
>>962477
>https://www.youtube.com/watch?v=cNjA0aee07k
MFW
>>962485
Feels good man.
>>962485
>he thinks the little shower head is a security device
Top keks these fucking anglos
>>961670
I like this post, you are big time.
>>962514
More like
https://en.wikipedia.org/wiki/Split-phase_electric_power
But you're still seeing two phases in your house that are 120 to N and 240 to each other. They aren't being transformed inside your meter like that crazy dude said.
>>962572
>>961664
okay i am wirer from the developing world
its really easy, see the way i learn it is:
electricity (from pole or generator) always needs to go to ground.
neutral is grnd. when you apply appliances to grid, it makes a short, the power goes in the live, and out the ground, shorting through whatever needs to take load, for your use (ballast, motor). here, is change at 50 hz, i think it is same. basically this happens, think, if you were to bicycle, and only move one side of the crank (pedal) down, and only down, you would fall off. electricity like this, it must go up, then peak to peak, to create harmonics for the motion of the energy. Otherwise it is too harmonic, if too high, otherwise it is fire if too low. do not worry about theory, you need not know it. the extra ground screw (green) (nobody uses) is so that in new places with fuses, or breakers, the power, if a fuck-up happens will not go on the metal casing of appliance, it will go into the ground, a seperate one from power earth. do not worry about ground, as most places hook energy directly to pole, sometimes hooks up to a meter. get this polarity out of your head, energy is energy. Also there are phases. this is important. singlephase, threephase no same-same. you must not use three phase, unless motor is made for it. if you are in a pinch and need to weld, get a metal hook to an insulated wire and throw it like shoes across the phases, making sure to get contact. they must be high voltage lines. you can clamp one phase to the ground electrode, if it is isolated, or you can use the pole (usually if it is dry and metal). CAREFUL as the current may leak into the ground and kill the people in the building if it is made of metal sheets. also, you do not need screws, Everything, is zip-tie. do not worry about the electricity code, nobody follow, only use your sense and your head.
>>962660
a few more tips,
if you need more light from a tube in a pinch, go ahead and hook both ballast wires to the tube, easier do when off, you get double lite from tube, it may die fast, but temporary. I do not know how to wire a fridge, they are not common, but most store buy old fridge scrap, put tube lights in, and fan, bam it looks like a fridge. you can also make magnetic ballasts for T12 tube, but is much complicated. electricity needs to find the ground. either you isolate, or bring it to ground through a device. paraffin electricity generators, you not run computer off.
you run light, motor, fan, no high technology. working on lines is simple, but you must do city lines, when at night, nobody see you, no large fines.
>>961705
Why would a regular household need a 3 phase connection?
Honest question.
>>962874
Few examples:
>Renewable heating etc. uses heat pumps or general pumps/ motors which require three phase above a certain power rating
>Larger HVAC systems
>/diy/ers with heavier machinery than your washing machine (e.g. lathes etc.)
>People with a requirement for a fairly substantial electrical supply (large homes etc. etc.)
![a5aeb949f1f94ce5a3c3f3633c34312f[1].jpg_itok=6FlskmRj.jpg](https://i.imgur.com/jLdKBnM.jpg "a5aeb949f1f94ce5a3c3f3633c34312f[1].jpg_itok=6FlskmRj.jpg")
>>962874
>3 phase
because it keeps ya Tesla toasty. Actually lived in the odd domestic with 3-phase, from simply being able to kill a phase and still have light etc. for troubleshooting, to running whtever the fuck you like without having to think, I miss it greatly.
>>962914
How did you go about with balancing loads etc?
Did the power company supervise at all or did they just let you go free and hoped you were in some way qualified...
>>962874
you don't
unless you are in a 3rd world 120v country
>>962896
what the fuck are you pumping? pro-tip: 'renewable' heating that requires a 3 phase supply is not saving you energy.
>3 phase lathes
>regular household
>>962914
why is it important to kill an entire phase instead of individual circuits at the breaker?
how did you kill a phase exactly? modifying a 3phase breaker or something? pulling a fuse? jesus.
>>962931
>what the fuck are you pumping? pro-tip: 'renewable' heating that requires a 3 phase supply is not saving you energy.
https://en.wikipedia.org/wiki/Heat_pump
>3 phase lathes
>regular household
Any decent sized lathe will want a three phase supply. VSDs don't magically save energy. If you have a certain motor that requires a certain amount of energy to provide a certain amount of work then you'll still need the exact same amount of electrical power to supply it.
VSDs are advantageous where you have HVAC systems etc. where running at 100% all the time would waste energy, e.g. running the fan at 20% at night when everyone's asleep.
>how did you kill a phase exactly? modifying a 3phase breaker or something? pulling a fuse? jesus.
If you're working on one phase and have the ability to isolate said phase then it's better than having the whole building supply off. As long as you have a safe and correct method of isolation then go for it.
>>962660
>basically this happens, think, if you were to bicycle, and only move one side of the crank (pedal) down, and only down, you would fall off. electricity like this, it must go up, then peak to peak, to create harmonics for the motion of the energy. Otherwise it is too harmonic, if too high, otherwise it is fire if too low.
What the fuck are you trying to say?
>>962939
I think he's trying to explain harmonic loads, it slightly makes sense on a very, very basic level.
>>961690
Funny story about live chassis... In our lab there are separate phases for some circuits, well turns out two out of the three phases were hooked to chassis and ended up being live. Roughly 70VAC between two of the chassis. Lets just say it only took a couple of shocks for some of my coworkers to realize that there was an issue...
>>962588
Split-phase is still single phase.
From the link you posted:
>Fig. 2 illustrates the phasor diagram of the output voltages for a split-phase transformer. Since the two phasors do not define a unique direction of rotation for a revolving magnetic field, a split single-phase is not a two-phase system.
The two lines inside your home are opposite ends of a single coil.
>>962969
Also, in a two-phase system, if you had 120v on each phase you would see 169v phase-phase rather than 240v.
>>962974
Well, that would depend on the angle between the phases, now, wouldn't it.
If the phases were opposed by, say, 180 degrees, you'd see 240v phase-phase.
>>962874
Swiss dweller here-
Here any high power domestic appliance is available in 3ph. Oven/stoves, washing machines, dryers etc. It's been handy for me as I do actually have some machine tools at home, so no need for converters and shit.
>>962419
No, I am in France.
>>962409
No need to be insulting, Anon. Homes are in TT neutral regime, so NO, neutral is NOT connected to earth in citizen homes, it is connected in EDF's low voltage transformers. At least in France, no clue for other countries (IMHO, should be the same for Europe + Swiss)
>>962475
Here an RCD is compulsory at the compulsory for all new installations.
>>963002
Two phase systems are 90 degrees.
180 degrees would be the same as hooking two coils in series. Which centre tapped would give you 240v to neutral and 480 line to line.
>>962156
>The only time you're going to have a transformer on site is large commercial or large apartment buildings, and then it's not going to be 240v
Yeah. Generator faggot here. The bus bars in our cabinets were fucking massive.
Line voltage is closer to like 13,000VAC and gets stepped down to whatever the store is going to be using, usually . Stores like Wal-Mart, Food Lion, etc have 3 phase power supplied to them. I never did residential, but our systems opened the mains (these breakers weighed about 70lbs) when it dropped power, generator spins up and generator breaker closes and is providing power in about 10 seconds, sometimes longer. Generator runs until mains come back up, at which point you match frequency exactly and voltage can be a little off, close mains breaker (if you don't match freq you'll try to use the generator like an electric motor aka reverse power). And then transfer the load back to the mains.
If they were providing 3 phase power to residential neighborhoods and you got 2-120V phases when you used two hots your voltage would only be 208, not 240. Hence 120/208 3 phase and 240/416 3 phase.
>>962874
Charging your electric vehicle.
On single phase it take hours.
>>961664
>how is ac mains polarized
Polarization is mostly a safety thing. If you install an Edison bulb outlet the metal on the outside should be neutral and safe to accidentally touch.
Neutral wire is safe to touch by itself the only time the neutral is unsafe to touch is when you're also touching the hot wire. Neutral is just a path to the ground.
Hot wire is energized and constantly shifts between +120V to -120V(or +/-240V, etc). Neutral wire never changes its voltage it's always "0V"(relative to ground). The hot wire is the one doing all the work, it's constantly pushing or pulling electrons down the wires.
