AC theory

[Chr!s]

It will be easier if you consider the star point to be at 0 V

 

[micknew]

Yes there will always be negative voltage on the neutral not measurable unless supply is under load.
This is due to the cable resistance.

 

[Chr!s]

You cannot not get a shock between N & E unless its connection at source is broken.
If its connection is broken the live will try to return to earth through you (if touched), giving you a shock.

Id disagree with that, its very possible to get a shock in that way

 

[Chr!s]

Yes there will always be negative voltage on the neutral not measurable unless supply is under load.
This is due to the cable resistance.

Why will it be a negative voltage?

 

[micknew]

Negative in relation to earth.

 

[Silly Sausage]

Thanks for your answers, really appreciated.

I guess what I am really stumped at is how can the current flow in the neutral if it is at zero volts.

There is simply no EMF to drive it along, this is where I am stuck.

If you touch the neutral at your light switch in your house it is at 0 Volts and if you touch the neutral at the transformer end it is also at 0 Volts so how does current move along it?

There must be some volt drop but just not enough to notice.

Time for a beer me thinks.

Draw a simple battery/lamp circuit with the -ve of the battery & you connected to earth.
Imagine a 250V battery.

The same current flows around that circuit at any point, irrespective of the voltage (at any one place)

You'd get get a shock from the +ve side of the lamp because there is 250V to you & earth, on the -ve side of the lamp there is 0V.

 

[i=p/u]

i too wonder at night sitting here thinking electrics how the current flows on neutral if no voltage, ahhh

 

[i=p/u]

but what about the flux giving back emf:hanged:

Draw a simple battery/lamp circuit with the -ve of the battery & you connected to earth.
Imagine a 250V battery.

The same current flows around that circuit at any point, irrespective of the voltage (at any one place)

You'd get get a shock from the +ve side of the lamp because there is 250V to you & earth, on the -ve side of the lamp there is 0V.

 

[Chr!s]

Negative in relation to earth.

No there would defiantly be a positive element there

 

[Chr!s]

As long as there is a PD current will flow

 

[Chr!s]

Draw a simple battery/lamp circuit with the -ve of the battery & you connected to earth.
Imagine a 250V battery.

The same current flows around that circuit at any point, irrespective of the voltage (at any one place)

You'd get get a shock from the +ve side of the lamp because there is 250V to you & earth, on the -ve side of the lamp there is 0V.

Well it wont quite be 0 V, therw will be some potential

 

[Knobhead]

How do I start this?
N & E are at the same potential supposedly but the line conductor RMS voltage rises to 300+V positive and drops to 300-V negative 50 times each second. Giving 100 changes per second. The average is 230V constant to neutral/earth. (Look up RMS voltage).

More to follow if you want.

 

[micknew]

No because the volt drop would be negative to the neutral.

 

[Knobhead]

No because the volt drop would be negative to the neutral.

What volt drop? What are you talking about?

 

[Chr!s]

No because the volt drop would be negative to the neutral.

Id forget polarity, were talking AC