Basic Home Electrical Question

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I've been reading up on basic home wiring. After I few pages I have one basic question that I need to get a good answer to before I read more.
All my reading refers to the black wire as the "hot" wire and the white wire as the "neutral" wire. Polorized plugs force the black wire on the outlet to connect to the black wire on the appliance.
The reason all this is supposedly done is because current flows from the black wire in the fuse box to the white wire the neutral bus bar in the fuse box.
Now why I may buy this "current flow" for direct current, it seems to run against the concept of alternating current.
Can someone set me straight on this topic? What EXACTLY do the terms "hot" and "neutral" mean?
Thanks
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I think I understand this a little better now thanks to everyone's responses.
Let me restate what I think some people have said plus what else I've managed to google.
If I pretend the electron flow was water instead of electrons, then what's happening is that the electric company is pushing and pulling "water" through the black wires at the rate of 60 cycles per second at an energy level of 120 volts, hence this is "hot".
The white wire, e.g. "pipe" is connected to a large calm lake, e.g. ground potential.
Now If I were to touch the white wire (assuming it was wired correctly to the "calm lake", it's just connected a resevoir of electrons at ground potential so there's no flow. However if I were to touch the black wire and provide a path to ground, then this "water" would be flowing through me, e.g. an electrical shock.
Is this at least a reasonable analofy of why black is "hot" and why white is "neutral"?
Thanks to everyone for their response.
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You got it pretty good. Don Young

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On 22 Oct 2005 18:32:00 -0700, snipped-for-privacy@hotmail.com wrote:

I think you might be confused with the terms AC and DC, current flow and electron flow.
In a DC circuit, current flow was described as flowing from the (+) terminal to the minus terminal (-). This convention existed since the days of Ben Franklin. However, electrons flow from the (-) terminal to the (+) terminal (the opposite direction to current flow). Electricians and circuit designers are interested in current flow. Electron flow might be of interest to a scientist.
In an AC circuit, the poles are changing 50 or 60 times a second. This has no effect on the magnitude of the current flow. The electron flow (unlike a DC circuit) will effectively be zero, but the AC current flow could be huge. Usually (just for convention) we say the current is flowing from the hot wire and back through the neutral, but this is just a concept, it actually does not have a direction.
Beachcomber
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Now If I were to touch the white wire (assuming it was wired correctly to the "calm lake", it's just connected a resevoir of electrons at ground potential so there's no flow. However if I were to touch the black wire and provide a path to ground, then this "water" would be flowing through me, e.g. an electrical shock.
Not exactly, when the white wire or neutral is part of a circuit, there is "flow", and if you were to cut that neutral wire and get between the two wires, or the live end and ground, there will be flow through you.

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Certainly, but only because the live end of the white wire is now a hot rather than a neutral.
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No, it has already gone through a resistor. It's a return seeking its neutral or ground to complete its circuit, and this fella needs to understand that if he gets in between it he's going to get hurt.

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Sure, it has been through a resistor (or at least a load of some kind...) so why isn't it still a hot? Take a 240v motor. It has three wires; 2 hots and a neutral. A hot goes to a winding and then to the neutral. When it comes off the winding it is not a neutral, it is simply a hot that has gone through the winding.
This is hair splitting; we certainly agree that the wire, whatever it is called, is potentially dangerous. But, I think it is still properly called a hot.
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to
not
called
A normal 240 volt motor only has 2 'hot' wires. There is no neutral. Both of the wires are 120 volts hot to ground in a normal home in the US. It may (should) have a ground wire going to its frame.
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Right.
Still, for all intents and purposes it is a hot. You're not going to find a significant difference between the lethality or voltage of a direct-from-panel hot, and one that's gone through a lightbulb on the way (if it's disconnected from neutral).
--
Chris Lewis, Una confibula non set est
It\'s not just anyone who gets a Starship Cruiser class named after them.
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I know Chris, I'm just trying to impress that on the OP. Reading some of his questions and responses, I just don't want him to be believing that neutrals are always benign

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I just love this group when you guys get in a spirited discussion about something so far removed from a direct answer to the question.
Too much schooling I guess.
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I was confused about this once myself. Do a google search; I am sure you will find some nice diagrams that explain it better than I can. (Hint: the neutral is always 0v, the hot alternates...)
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The "neutral" wire is at ground potential. The "hot" is (usually) 120vac relative to the neutral. The hot doesn't have to be black, although thats the most commonly used color. White must be the neutral. Green must be the ground. Any other color can be used for the hot. True with A.C. the current flow goes back and fourth. Its the voltage relative to neutral that defines the hot.
--
Rich Greenberg Marietta, GA, USA richgr atsign panix.com + 1 770 321 6507
Eastern time. N6LRT I speak for myself & my dogs only. VM\'er since CP-67
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Rich,
Not that I would do this (AND I RECOMMEND NO ONE ELSE DO THIS EITHER), but does that mean that when replacing a switch or an outlet, that I could turn the power back on and touch the NEUTRAL (white) wire and not receive a shock?
Wardell
..panix.com/~richgr/ Asst Owner:Sibernet-L
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If the outlet is wired correctly you could touch the Neutral (usually white) while grounded and not get shocked. The Neutral is suspose to be grounded back at the service entrance/panel box.
To answer your question above, the electricity does not actually come out of the black wire and return on the white wire. That is just simple thinking to make it easy to explain the circuit.
In most homes in the US there are 3 wires comming in. There are 2 hot wires and one neutral. There are 240 volts across the two Hot wires and 120 volts from the neutral and either hot wire. If only 240 volt devices are used then there is no need for the neuteral wire. If you start adding 120 volt devices , some on one side and some on the other side then the current will be unbalanced on the hot wires and the neuteral will have some current on it. If you could put the same current load on each side of the two circuits then there would again bo no current flow on the neutral wire and it could be disconnected and the devices would continut to work normally.
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On a properly wired system that is working properly you are able to touch the bare/green wire or the white wire and not receive any shock. Only the hot wire, usually black has any shock potential.
And please don't try this at home kiddies, as long as you aren't grounded you can handle the hot wire with the juice on. Electricians do it all the time while standing on a fiberglass ladder. You can get a nasty shock changing an outlet live because the ground wire connect to the part of the device you are holding. Please remember that even a 110V circuit can kill you it the right situation.
And for the OP: I am not qualified to explain it to you but the term alternating current refers to what happens before the electricity enters your home. There are two generators working in a 60HZ cycle that feed juice to the line. Somehow this permits more juice to flow farther at a lower cost. That is an extremely simplified explanation. But it is about all I can explain.
Colbyt
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As long as there's nothing connected to the circuit that is drawing power. However, if there's current going through the circuit, anwhere on that particular circuit (wires connected to the same breaker) there's going to be some voltage potential because there's a resistance from that white wire back to the breaker box. Now the voltage is most likely low (less than a volt) so unless you are sticking a white wire in your mouth and the ground wire up your ass, the likely hood is nearly zero that you will feel a shock.
The best thing to do is wear rubber bottom sneakers and synthetic gloves if you plan on working on a powered circuit and you are a novice.

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If you're a novice (or anything less than a pro...) TURN OFF THE POWER!!!
Brad
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The first time I tightened the connections on my main breaker I did exactly that, while holding an insulated allen wrench. I knew it was silly, but it was the MAIN BREAKER.
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