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# Difference between Neutral and Earth wire ?

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#### avinsinanan

##### New Member
Hello,

I am trying to find out the main differnce between the neutral wire and earth wire.

I mean both with respect to a 3 phase system. I mean both of them should have a potential of zero volts.

So this should mean we should be able to use the neutral as the ground wire.

If you cannot what is the advantage of each wire?

Thanks

Yours Respectfully
Avin Sinanan

In a 3 phase system, the neutral carries the unbalance current. The earth ground is not supposed to carry any current unless there is a fault.

earth

As company supplies enter premises is not the neutral line not in fact the earth!.

The neutral line is connected to earth, but the earth is not carrying significant current. Telephone lines, at one time, actually did use the earth as the return conductor. It is an interesting fact, that two probes placed in the earth 1 meter apart will read a certain resistance. Placed 10 meters apart or 10,000 meters apart, the resistance will be the same, if the earth is uniform.

Neutral & earth.

Thanks for the reply, is this current carried by the earth however insignificant, ie, can it be measured, obviously it is so low that it will not trip ecb's or does it!...on reflection i recently replaced my kitchen with new unit's and disconnected all earthing necessary to fit the new sink etc, i did however notice as i connected the new sink to the modified plumbing a tiny spark was noticeable as i made contact with both copper pipes is this earth leakage?.

Resistance & probes.

If the resistance measured at 1 or 10 metres apart is the same as 10Km how was this proven scientifically with my probe leads i can only measure the metre

The induced voltages you can measure between Earth and Neutral can reach high values.

Whats the power that can be taken from this induced voltages ?

regards
asena

The induced voltages you can measure between Earth and Neutral can reach high values.

Whats the power that can be taken from this induced voltages ?

regards
asena

It's never been stated what country the thread originator is in (and he's not entered his location), so presumably there may well be differences between countries.

In the UK (as far as I know, I'm not an electrician) there are two options for earth.

1) The older way (and probably still the best?), you provide your own earth connection with an earth spike in the ground, regulations require the wire to the spike to be a certain minimum thickness, and the spike has to comply as well.

2) The electricity company provide you a PME earth, I've no idea what that actually is, but assume it's using the neutal wire in some way?.

Also, as far as I'm aware, the neutral connection is grounded at the substation, which is why you can get a shock off just the live wire.

Usually, and depending on load, you can measure a few volts different between neutral and earth - due to the drop across the neutral wire from the substation.

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