PC electricity issue

[mikehende]

I don't understand what Mike Meyers means in the book or can it be I misinterpreted his words? Here is exactly what is written on page 291:

" Caution
Flipping the AC switch on the back of the power supply can wreak all kinds of havoc on a pc. Moving the switch to ~230v in the U.S. makes for a great practical joke [as long as the pc is off when you do it]-the pc might try to boot up, but it probably won't get far. You don't risk damaging anything by running at half the AC. In countries that run ~230 standard, on the other hand,, firing up the pc with the AC switch set to ~115 can cause the power supply to die a horrid, smoking death. Watch that switch!"

Now here's the thing guys, shouldn't this be the reversed because if you have an outlet with 220v of pressure in it and you hook up a piece which requires only 115v of pressure then you would be sending twice the required amount of pressure into the piece, is this not so?

Alternatively, if you plug a piece which requires 220v into an outlet that has only 115v of pressure in it then this should be safe becuase you don't have enough pressure to run the piece of equipment much less, do any damage to it.

So what I would like to know here please without beating around the bush, is Mike Meyers wrong here, yes or no?

[mikehende]

Come to think of it, looks like I was reading this wrong, looks like Meyers is referring to "setting the switch" on a unit.

[mikehende]

Any electricians on this forum who can explain basic electricity please? I have a few specific questions.

[Seth]

Any electricians on this forum who can explain basic electricity please? I have a few specific questions.

Well, I'm not an electrician, but I'm sure I can answer some basic electrical questions.

Keep in mind that electrical "pressure" indicates the amperage and not the voltage.

[mikehende]

Great, thanks! I am being told that the Neutral wire is the "return" path to send the electricity back to the power power plant, if this is so, why? I am comparing this to a what is in the Mike Meyers A+ book which says the Hot wire brings in electricity like a pipe brings in water so my question is, if you open your tap and use water, that water is lost so I am figuring if you use elcetricity, then it shlould be lost or used up so how can it be returned to the plant and why?

[Seth]

Great, thanks! I am being told that the Neutral wire is the "return" path to send the electricity back to the power power plant, if this is so, why? I am comparing this to a what is in the Mike Meyers A+ book which says the Hot wire brings in electricity like a pipe brings in water so my question is, if you open your tap and use water, that water is lost so I am figuring if you use elcetricity, then it shlould be lost or used up so how can it be returned to the plant and why?

Unlike the water analogy, there is no electricity "lost" in an electrical circuit. The total energy is either used by the consuming device, or it isn't.

I have no idea what Mike Meyers is referring to about the neutral wire sending electricity back to the power plant. As far as I know, the neutral wire is for safety purposes, and shouldn't have any significant current flow unless there existed a short circuit.

That's about all I know regarding the wiring. Although I'm sure the internet has a ton of information regarding specific electrical wiring.

[mikehende]

unfortunately, the info on the net doesn't answer the questions which is why I am trying to get help with this from an electrician, appreciate you trying to help!

[mommalina]

mikehende, did you search the net for a forum for electricians? It may be worth the effort. I found some helpful information once on a forum for plumbers. Saved me some money.

Good luck.

Lina

[mikehende]

I joined 3 forums last week and no luck so far, also found a great one which is a dedicated electrician's forum but they will only help you with a project [just like your situation with the plumbing] and do not wish to "teach" you basics, another problem I am running into is that some electricians know what to do in specific situations but either they don't know or can't explain the more "scientific" parts of my questions.

[dbarrow]

http://www.rocketroberts.com/techart/power.htm

[PeteF]

Great, thanks! I am being told that the Neutral wire is the "return" path to send the electricity back to the power power plant, if this is so, why? I am comparing this to a what is in the Mike Meyers A+ book which says the Hot wire brings in electricity like a pipe brings in water so my question is, if you open your tap and use water, that water is lost so I am figuring if you use elcetricity, then it shlould be lost or used up so how can it be returned to the plant and why?

Hi Mike,
Part of your frustration to get an answer on this issue is the complexity
of the answer. The answer requires reading several chapters in a basic
electrical theory text book. Your public library is a good source for that
and diagrams go along way to explaining it.

Now let me see if I can explain it very simplly in a few sentences but
please don't ask me to explain further because I can't explain it as
well as a text book can.

Electricity requires a "complete path" from the source. You can think about
it similar to water & plumbing, but it's not the same in that the "water"
will not continue to flow once the "complete path" has been broken.
In other words, electricity can NOT spill out the end of a wire as
water can flow out of a pipe.

So, understanding that electricity requires a complete path "out of"
and "back to" the source is key to understanding electricity flow.

Now it get's more complicated because you can have AC or DC
current. DC flows in one direction only on its' complete path.
AC flows in both directions by alternating it's flow. Ordinary
household AC alternates its' flow 60 times a second on it's
"complete path".

Ok, now back to your basic question.
In any electric circuit, AC or DC, you have a source, a complete path,
and a load. The source provides a constant current flow if the load
remains constant. The load uses up the power, but the source keeps
providing more power until the source runs out of power and at that
point the current on the complete path stops flowing.

This talk about "neutral wire" or "return path" is not that meaningful,
especially when talking about AC flow. It's usually just a reference to
which side of the complete path they are talking about, but really
it's just one big loop.

.......|~~~~~~~~~~~|
Source......................load
.......|~~~~~~~~~~~|
....... Neutral/ReturnPath

Get the picture?

---pete---

[mikehende]

Aprreciate you trying to help Pete but all of the diagrams and tutorials on the net which I have come across doesn't cut it for me [and some others on the A+ [forum]but I am making progress, this is where I'm at right now, concerning the "flow" of electricity, I need to know if this is how the electricity flows in from the street and out again? In particular, looking at the wall AC outlet, is that the path of the electricity, to flow from the Live slot through and to the Neutral slot then back out through the Neutral wire?

[kelly]

Electrical power is the result of a flow of electrons through a path. The electrons start at one point, the negative terminal, and flow to the positive terminal. The pressure behind the electrons is called voltage. The amount of electrons flowing in a period of time is called current, measured in Amperes. It's the flow of electrons that make electrical devices work. Kind of like how the flow of a river makes turbines turn.

Wattage is a combination of voltage and current. In a DC circuit, like the circuits inside a computer, wattage is calculated by multiplying the voltage (in Volts) by the current in Amperes. So if your hard drives requires 12V of pressure and 100 miliamps (0.10 Amps) of current then it requires 1.2 Watts.

AC circuits are similar however, there are factors that affect the wattage due to phasing of voltage and current which I never really understood. So DC wattage is not always exactly equal to AC wattage, but it'll be close.

-td

[kelly]

Pete - good description. Didn't see it before I posted mine. We were both typing at the same time.
-td

[PeteF]

this is where I'm at right now, concerning the "flow" of electricity, I need to know if this is how the electricity flows in from the street and out again? In particular, looking at the wall AC outlet, is that the path of the electricity, to flow from the Live slot through and to the Neutral slot then back out through the Neutral wire?

Think of the main circuit breaker panel as the SOURCE.
Actually you can think of the outlet as the source too.

Forget this notion that the electricity flows in a certain direction
becasue that only applies to DC. Your house is AC.

The path is very simple, you have the source and the load
conected by 2 wires. One wire is referred to as the HOT,
the other is referred to as the Neutral. The Neutral wire
is at the same potential as the Ground.

Mike, I'm starting to get frustrated in answering your question
becasue I can't figure out why you need to know the things
you are asking. Can you explain the practical aspects behind
your questions?

---pete---

[mikehende]

Mike, I'm starting to get frustrated in answering your question
becasue I can't figure out why you need to know the things
you are asking. Can you explain the practical aspects behind
your questions?
---pete---

Pete, you have no idea how frustrated I am [lol] so I can understand what you're saying. As far as the practical aspects behind my questions? I have NONE. This thing is eating away at me, don't know why and I can't control it, that's the best honest explanation I can give to you. Just don't bother replying to this thread Pete [and anyone else] if it's frustrating you, no sense in two or more us getting in this state of mind.:)

[mikehende]

Now this is more of what I was looking for all this time

http://www.thetech.org/exhibits/online/topics/1xb_flash.html

[PeteF]

Now this is more of what I was looking for all this time

http://www.thetech.org/exhibits/online/topics/1xb_flash.html

Yeah Mike, that animation reminds me of my classes in basic electronic theory.
All you need to do is get a book on the topic and read the first few chapters.

---pete---

[mikehende]

found another great one here

http://www.members.shaw.ca/len92/electricity.htm

Tel me if I am correct here Pete, if a person should place an object like a regular screwdriver into an AC wall receptacle, normally that person would get shocked, is this becuase that person now becomes a conductor of electricity becuase he/she is standing on the ground and so creates a circuit so the charge goes through him/her into the ground? If so, then if that person should be wearing "rubber" boots, the person should NOT get shocked because the rubber is breaking the circuit, is this all correct?

[PeteF]

found another great one here

http://www.members.shaw.ca/len92/electricity.htm

Tel me if I am correct here Pete, if a person should place an object like a regular screwdriver into an AC wall receptacle, normally that person would get shocked, is this becuase that person now becomes a conductor of electricity becuase he/she is standing on the ground and so creates a circuit so the charge goes through him/her into the ground? If so, then if that person should be wearing "rubber" boots, the person should NOT get shocked because the rubber is breaking the circuit, is this all correct?

Correct!
Your body needs to be part of the complete path. Since the Neutral
side of house wiring is at the same electrical point as ground, a person
standing on the ground completes the path when they touch the HOT
side.

PS: Be careful becasue many times buildings are not wired correctly
and you could get shocked by touching the neutral side of the circuit.

---pete---

[mikehende]

Thanks Pete, to go one step further, if you place the screwdriver in the Neutral slot then nothing should happen you regardless of what you're wearing, correct?

[kelly]

This is why a bird on an electrical wire doesn't get shocked. There is no return path for the electircity to go to.

[PeteF]

Thanks Pete, to go one step further, if you place the screwdriver in the Neutral slot then nothing should happen you regardless of what you're wearing, correct?

Theoretically, that's true but don't try it!
If the wiring is not installed properly you can still get killed.

Invest in an AC outlet tester.
http://www.radioshack.com/sm-see-all-needs-and-wants--pi-2103169.html

---pete---

[mikehende]

That's very cheap so that's good, what kinds of faults does it detect? Specifically, can it tell you which slot is Hot so you can determine which wire is the hot?

[PeteF]

That's very cheap so that's good, what kinds of faults does it detect? Specifically, can it tell you which slot is Hot so you can determine which wire is the hot?

It tells you if the...
* Hot & Neutral is Reversed. [Neutral is the larger slot on the left (I.I) ]
* Hot is open
* Neutral is Open
* Faulty ground

For any new PC installation, testing the AC outlet for proper wiring
should be first on the list.

Same for any UPS or powerline conditioner installlation. A powerline
protection product can be rendered useless if the AC outlet is
not wired properly.

---pete---

[mikehende]

For any new PC installation, testing the AC outlet for proper wiring
should be first on the list.
Same for any UPS or powerline conditioner installlation. A powerline
protection product can be rendered useless if the AC outlet is
not wired properly.

---pete---

Great tip, thanks! Ok Pete, inquiring minds would like to know what the procedure will be if the tester shows that Hot and Neutral is reversed? Should I then reverse the wires the way it should be?

[PeteF]

Great tip, thanks! Ok Pete, inquiring minds would like to know what the procedure will be if the tester shows that Hot and Neutral is reversed? Should I then reverse the wires the way it should be?

If you have to ask that, it means you need to call an electrician.:)
Seriously, don't mess with it, you can get electricuted.

---pete---