240 ac

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Old 08-02-12, 12:51 PM
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240 ac

A lot of the world has 240 AC . They dont split it at the mains. Does this mean that house wiring in these countries does not have a neutral wire?? There would be no imbalance of loads in the house ,no??? Is there a primary neutral on the poles in those countries??
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Old 08-02-12, 01:00 PM
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Actually it is more likely 220 volts not 240 volts.
They don't split it at the mains.
Correct, no center tap on the secondary of the supply transformer but the techcnical name for neutral is grounded conductor and they do have a grounded conductor just like we do.
Is there a primary neutral on the poles in those countries??
As far as I know there isn't but you don't have primary neutral in the US either.

There is wide variations though from country to country. Japan can be as low as 100 volts and some areas in Scandinavia as high as 440 residential. Wikipedia has a good article on this.
 
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Old 08-02-12, 05:42 PM
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my single phase residential line has a bottom wire neutral on the poles and its attached to ground wires also. you only need a neutral for imbalanced loads,no???
 
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Old 08-02-12, 05:46 PM
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Your house is supplied with 240 volts. The neutral is used to derive 120 volts from one leg of the 240v.

 
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Old 08-02-12, 06:37 PM
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The neutral will only carry the imbalance in a 120/240 volt circuit. In a 120 volt circuit the neutral carries the same load as the hot conductor.

You can make any voltage you want with transformers. There is just standard voltages available that manufactures make. Just imagine a transformer like this:
Attachment 2396
Note it is not a neutral, but the grounded conductor.
 
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Old 08-02-12, 06:58 PM
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A wire halfway up the pole serves as "neutral" (return) for the primary circuit, neutral for the secondary circuits, and ground. At every other (if not every) pole a wire from it goes down the pole to a ground rod at the pole base.

Where the draw (amperes) in the primary circuit is not too great the primary circuit may use earth as a return (to the substation). Here the "neutral" halfway up the pole goes only between those poles between which the hot wires for the secondary circuit of any given transformer are strung.

Where power at the receptacle is 220/240 volts it is common to have two hot wires sharing a common or "neutral" or grounded conductor with 440/480 volts from hot to hot. With this system it is also common for any given house to have just 220/240 volts with one incoming hot line and the neutral.
 
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Old 08-05-12, 10:55 AM
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according to IronHand then.. if you are using a 120 fan in the house and touched the white wire you would get a shock. What about touching the bus bar when a 240 load is going??
would it shock you??
And about returns to the substation... many people who dont know much about electricity
would think the juice in your home goes thru your appliance and then back to the pole
and then to the substation and on and on in a loop. This is not correct really is it??
When you use the juice it is mostly used up and most of the sine wave is gone, replaced by new sine waves,no?? Once juice is used it has to be replaced by new juice....
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Old 08-05-12, 03:02 PM
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If you are using a 120 volt load, and get in between that load and the neutral wire, yes, you will get a shock. It would not be 120 volts since you would be in series of the circuit, and the voltage would therefore drop because of the resistance of the load.

And about returns to the substation... many people who dont know much about electricity
would think the juice in your home goes thru your appliance and then back to the pole
and then to the substation and on and on in a loop. This is not correct really is it??
Yes, that is correct.

When you use the juice it is mostly used up and most of the sine wave is gone, replaced by new sine waves,no?? Once juice is used it has to be replaced by new juice....
No. Electricity is not "used up" like gasoline, it is the flow of electrons. In order for the electrons to flow there must be a complete circuit. The power plant is nothing more than a pump that moves electrons using a magnetic field. There is only one sine wave but the point where the wave is depends on where you are taking your reading.
 
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