The difference between Ground and Neutral?

Neutral is the point (in a polyphase system) from which all the individual phases are equi-distance in the phase angle and the amplitude.

Or in a 3 phase system, the most common one, if you phasor sum the three phases, the resultant is the neutral point.

The Ground (or earth) is as the name indicates the potential of earth and for all purposes it is the reference potential ie 0 value.

NEUTRAL is the origin of all current flow. In a poly-phase system, as it's phase relationship with all the three phases is the same, (i.e.) as it is not biased towards any one phase, thus remaining neutral, that's why it is called neutral.

Whereas, GROUND is the EARTH on which we stand. It was perceived to utilise this vast, omnipresent conductor of electricity, in case of fault, so that the fault current returns to the source neutral through this conductor given by nature which is available free of cost. If earth is not used for this purpose, then one has to lay a long. long metallic conductor for the purpose, thus increasing the cost.

However, Neutral may be earthed or may be left unearthed.

Here is another question, Can there be any potential difference between the Ground and the Neutral? Won't it cause problem if they're shorted? Can the Ground be used as Neutral and vice versa?

Thanks for your answers.

There may (and it does exist) a potential difference between the ground and neutral.

The question is how much. For different purposes there is a different limit put on this voltage.

One aspect is safety - when some one touches a neutral, you don't want him to be electrocuted - do you? Usually if you see the switches at home are on the phase and not neutral (except at the MCB stage). Any one assumes the once the switch is off, it is safe (the safety is taken care of in 3 wire system, but again most of the fixtures are on 2 wire) - he will be shocked at the accidental touching of wire in case the floating neutral is floating too much.

The second aspect are the electronic instruments eg computers where the ceiling on it is very high. In my place servers have been destroyed by it.

The additional aspect is insulation- sometimes the equipments have graded insulation ie the insulation in the neutral side is much weaker than the phase side.

The lase question - No. Ground should never be used as neutral. The protection devices (eg ELCB, RCD etc) work basically on principle that the phase currects are balanced with neutral current. In case you use ground wire as the neutral, these are bound to trip if they are there - and they must be there. at least at substations. And these are kept very sensitive ie even minute currents are supposed to trip these.

And secondly earth electrodes are not meant to carry large currents- and electrodes may degenerate very fast if exposed to large currents.

When neutral is connected to ground the significant difference is that ground must not carry current or it would be unsafe for you to touch.

Ground is earth ground Neutral is the other that the hot wire.

Because you're asking the question, I'm assuming you're probably thinking of the wiring in your house. Your local utility sends you electricity along the "hot" wire or "line", which goes through the wall switch, to your "load" (lights, etc), then returns through the "neutral" wire back to the utility. Sort of like a bus making its loop.

The "neutral" is normally connected to the "ground" wire which is in fact connected to mother earth at the main electrical panel in your house. The idea is to anchor the incoming voltage to the earth ground so it can not float at any higher level.

The ground wire is also used to act as an electrical barrier around appliances to prevent a shock hazard. For example, your fridge will have a three pronged plug wired so that the "line" and "neutral" are connected to the flat pins, and the rounded "ground" pin is connected to the walls of the fridge. Then, if the "line" wire breaks or falls off and touches the walls of the fridge, it gets shorted to ground and blows a fuse. Without the ground wire, you would get a shock when opening the fridge.

You may notice that a lot of appliances nowdays don't have this rounded ground pin, but that the two flat prongs in the plug are different width, thereby polarizing it. This is another method of protection usually referred to "double insulation" where the manufacturer builds the device in such a way that the "line" wire can not possibly come in contact with the housing.

Grae

Is the neutral connected to the ground?

In our area the neutral is connected to ground at the distribution transformer stage only and not at the individual homes. The house wiring is two wire (Phase+neutral) or 4 wire (RBYN - for 3 phase) all from the distribution line. The tapping is never single wire.

In case the neutral is earthed (I doubt it, for various reasons, but may be in certain area codes it is permitted) then it has to be ensured that it is done outside the ELCB stage else the ELCB will not pick-up/ will false signal the earth fault.