Originally posted by n9xv@Jan 20 2006, 07:28 PM
The branch wiring extending out of the breaker pannel is all parallel from the source. A load connected to the individual outlets however, constitutes a series circuit. For example, A light bulb connected to an outlet is indeed a series circuit.
You can expand the idea to 100s of light bulbs "parallel" connected across the outlet. However, the 100s of light bulbs reduced to their equivalent resistance constitutes a series circuit with regard to that individual 120-volt outlet.

A 120-volt circuit has only one hot wire. A 240-volt circuit has two hot wires.

Above, you said;

"---the neutral wire would have the sum of the two HOT WIRES CURRENT FLOW."

Thats exactly right! because at that point you have a SERIES circuit and would indicate the sum total of ALL the individual return currents from ALL of the PARALLEL branches.

[post=13302]Quoted post[/post]​

Hi, n9xv, it appears as though we now have acommon position on the NEUTRAL WIRE. But you have introduced two new pieces of CONFUSION. 1 -"a light bulb connected to an outlet is indeed a series circuit. NO SIR !! This is called a SIMPLE CIRCUIT . A series circuit would have to have at least two components( and not one) connected end to end. YOU then reduced 100 paralell bulbs to a series circuit out of the same confusion. 100 light bulbs in paralell is just that a -PARALELL CIRCUIT. 2 You agree that the NEUTRAL WIRE would have the sum of the two HOT WIRES and thus you have a SERIES CIRCUIT. This is an incorrect conclusion.In a SERIES CIRCUIT the current is the SAME.THESE CIRCUITS DO have unbalanced loads.The current thus are NOT the SAME You add current in PARALELL CIRCUITS. So if you agree the NEUTRAL WIRE carries the sum of the TWO HOT WIRES ,this has to be a PARALELL CIRCUIT. My only interest in engaging in this exchange is because of the number of persons who read these posts.

 

Originally posted by alim@Jan 21 2006, 09:41 AM
Hi, n9xv, it appears as though we now have acommon position on the NEUTRAL WIRE. But you have introduced two new pieces of CONFUSION.  1 -"a light bulb connected to an outlet is indeed a series circuit. NO SIR !! This is called a SIMPLE CIRCUIT . A series circuit would have to have at least two components( and not one) connected end to end.  YOU then reduced 100 paralell bulbs to a   series circuit out of the same confusion. 100 light bulbs in paralell is just  that a -PARALELL CIRCUIT. 2 You agree that the NEUTRAL WIRE would have the sum of the two HOT WIRES and thus you have a SERIES CIRCUIT. This is an incorrect conclusion.In a SERIES CIRCUIT the current is the SAME.THESE CIRCUITS DO have  unbalanced loads.The current thus are NOT the SAME You add current in PARALELL CIRCUITS. So if you agree the NEUTRAL WIRE carries the sum of the TWO HOT WIRES ,this has to be a PARALELL CIRCUIT. My only interest in engaging in this exchange is because of the number of persons who read these posts.

[post=13306]Quoted post[/post]​

Ok, lets walk through it a bit. I'am breaking up the above post so as to keep focus on the individual topics. I'm not trying personnaly discect you! No disrespect intended.

Here goes;

1 -"a light bulb connected to an outlet is indeed a series circuit. NO SIR !! This is called a SIMPLE CIRCUIT . A series circuit would have to have at least two components( and not one) connected end to end.

For the sake of discussion I'am going to assume "conventional" current flow or HOT to GROUND.

The current in a series circuit is the same throughout all part of that series circuit. In the lightbulb example, the current flows from the hot side of the source (the outlet) through the filament of the bulb and through the return or nuetral/ground lead back to the source (outlet). There is no "part count" requirement in order to have a series circuit. You can call it a simple circuit but any/all circuits can be reduced to a simple circuit of one form or another. I just did that in the previous post. From the point of view of the current, (which is of ultimate concern as current is what produces meaningfull results) it is a series circuit. No where in that circuit is current different from the point it leaves the source to the point it returns to the source. Another example of the same thing is a resistor connected to a battery. The resistor is connected "across" the battery so you might call it a "parallel" circuit but it is a SERIES circuit. Why, because the current is the same throughout that entire circuit. A bare wire connected across a battery (or any voltage source) is a series circuit. Current flows from the battery through the wire back to the battery and through some internal resistance back to the lead from which it came.

2 You agree that the NEUTRAL WIRE would have the sum of the two HOT WIRES and thus you have a SERIES CIRCUIT. This is an incorrect conclusion. In a SERIES CIRCUIT the current is the SAME.THESE CIRCUITS DO have unbalanced loads. The current thus are NOT the SAME You add current in PARALELL CIRCUITS. So if you agree the NEUTRAL WIRE carries the sum of the TWO HOT WIRES ,this has to be a PARALELL CIRCUIT.

Again, From the "breaker pannel" where raw power comes in from the utility company - if you disconnect the ground wire and insert an ammeter (or clamp on meter) you will read the sum total of ALL the branch currents from the pannel. The sum total of all the branch currents that combine and are read through the SERIES circuit from the point you are taking the reading. If you disconnect ground from the breaker pannel, your whole house will be dead because you've interupted a SERIES circuit at that point and thus, no current can flow. Of course in reality you'll get all kinds of weird "readings" as things "float" with no ground. But try pluging in hair dryer or TV - it wont work!

My only interest in engaging in this exchange is because of the number of persons who read these posts.

And I hope someone gets some usefull information from it too! I'd like to here from shelly50 to see where she is with her delima.

 

Example of the 120VAC outlet, simplified series circuit.

 

1st of all because ur boss said so DOSN'T mean it's right

but because u're employee so just node ur head and agree

 

Originally posted by n9xv@Jan 21 2006, 02:03 PM


Ok, lets walk through it a bit. I'am breaking up the above post so as to keep focus on the individual topics. I'm not trying personnaly discect you! No disrespect intended.

Here goes;

1 -"a light bulb connected to an outlet is indeed a series circuit. NO SIR !! This is called a SIMPLE CIRCUIT . A series circuit would have to have at least two components( and not one) connected end to end.

For the sake of discussion I'am going to assume "conventional" current flow or HOT to GROUND.

The current in a series circuit is the same throughout all part of that series circuit. In the lightbulb example, the current flows from the hot side of the source (the outlet) through the filament of the bulb and through the return or nuetral/ground lead back to the source (outlet). There is no "part count" requirement in order to have a series circuit. You can call it a simple circuit but any/all circuits can be reduced to a simple circuit of one form or another. I just did that in the previous post. From the point of view of the current, (which is of ultimate concern as current is what produces meaningfull results) it is a series circuit. No where in that circuit is current different from the point it leaves the source to the point it returns to the source. Another example of the same thing is a resistor connected to a battery. The resistor is connected "across" the battery so you might call it a "parallel" circuit but it is a SERIES circuit. Why, because the current is the same throughout that entire circuit. A bare wire connected across a battery (or any voltage source) is a series circuit. Current flows from the battery through the wire back to the battery and through some internal resistance back to the lead from which it came.

2 You agree that the NEUTRAL WIRE would have the sum of the two HOT WIRES and thus you have a SERIES CIRCUIT. This is an incorrect conclusion. In a SERIES CIRCUIT the current is the SAME.THESE CIRCUITS DO have unbalanced loads. The current thus are NOT the SAME You add current in PARALELL CIRCUITS. So if you agree the NEUTRAL WIRE carries the sum of the TWO HOT WIRES ,this has to be a PARALELL CIRCUIT.

Again, From the "breaker pannel" where raw power comes in from the utility company - if you disconnect the ground wire and insert an ammeter (or clamp on meter) you will read the sum total of ALL the branch currents from the pannel. The sum total of all the branch currents that combine and are read through the SERIES circuit from the point you are taking the reading. If you disconnect ground from the breaker pannel, your whole house will be dead because you've interupted a SERIES circuit at that point and thus, no current can flow. Of course in reality you'll get all kinds of weird "readings" as things "float" with no ground. But try pluging in hair dryer or TV - it wont work!

My only interest in engaging in this exchange is because of the number of persons who read these posts.

And I hope someone gets some usefull information from it too! I'd like to here from shelly50 to see where she is with her delima.

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Hi To all concerned. THIS WILL BE MY LAST RESPONSE ON THIS TOPIC. n9xv,each time he posts he introduces. another CONFUSION.He says"if you disconnect ground from the breaker panel ,your whole house would be dead"---THIS IS TOTALLY INCORRECT!One point I want to make A device across avoltage source satisfies the definition for a PARALELL circuit, it also behaves as a SERIES circuit,--This SIMPLE CIRCUIT is used for circuit explanation,in class rooms,AND IS NOT CONSIDERED A SERIES CIRCUIT BY ELECTRICAL TEXT BOOKS OR BY ELECTRICAL TUTORS.

 

I am totaly confused about the US outlet. could you please explain me the difference between 120 and 240V outlets? I allways thought it is like in the picture, but you say that if two loads are connected to the HOT points and the ground, the current adds in the ground wire. That means the HOT points are in-phase and not 180deg, which is said in some other post.

And for better simplicity about the gound/common/black/hot problem, i suggest using that "phase tester" or how do you call it, you hold in hand and it glows when you connect it to phase.

 

I suspect we have less of a "disagreement about theory" and more of a communications glitch.

Part of this is my fault. I missused the word "carry." Current does indeed flow through the neutral of a 110vac circuit. "Carried" current is, by definition, limited to the imbalance current. If the imbalance current is zero, then the "carried" current is zero - regardless of how much current is flowing. 110vac circuits don't have imbalances.

N9xv's description of "parallel" and "serial" may seem confusing, but it is nonetheless accurate. Outlets on a branch circuit are in parallel. Equipment plugged into those outlets will be in series with the breaker, and in parallel with each other.

Current flowing through the neutral of a 110vac branch ciruit will be equal to current through the hot wire of the same circuit. That current might not be equal throughout the branch circuit, as some equipment may be utilised in different physical locations than other equipment.

Current flowing through the hot leads of an American 220vac circuit will be 180 degrees out of phase. Kubeek's diagram is correct. A 220vac arc welder will load both sides of the circuit equally and no current will flow in the neutral. A 220vac cloths dryer will load one side more than the other and the neutral will carry the imbalance current.

As far as voltage on the neutral...
The neutral will be at zero volts when we measure it on the bussbar in the breaker box. But please remember that copper does indeed have resistance. A 250 foot chunk of #10 will be about a qaurter ohm. Depending on circuit current being drawn by the load, we might indeed see a couple volts to ground on the neutral at the outlet. This is why authorities don't like exposed neutrals.

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Perhaps the original thread topic also deals more with a miscommunication than with disagreement on theory?

 

I just want to comment on the last few points;

alim, sorry for the confussion but the "rules" are'nt mine. Someone worked all this stuff out long before me. All I can say is - if you can run your house without a ground then theoretically your not drawing any current. If so, that means your not using (or being billed for) any power. Tell us more about that . . .

kubeek, your drawing is correct as was stated by thingmaker3. In the 240-VAC circuit, when the voltage on one "hot" wire swings positive, the voltage on the other "hot" wire swings negative with the same amplitude. In other words, one side goes +120 volts & one side goes -120 volts, both in equal amplitude but 180-degrees out of "time" or phase. Just like on a number line, from -120 to +120 = 240. Everything on a single 120-volt circuit would be of the same phase. Assuming all purely resistive loads.

I think thingmaker3 "gets" what I'am illustrating. I'am looking at the circuits in a simplified "reduced" form. You can understand something better when its in its simplest form. The rules of electronics/electricity still apply and have not been broken. My thanks to thingmaker3 for the articulate input.

I wonder how shelly50 is doing? I hope she's not fighting with the boss. She sounds like a smart cookie, probably deserves more money anyway!