Neutral Grounded? Does It close the Circuit?

[gauthamtechie]

In a three pin plug socket-the ones with earth, live(or hot) and neutral, I see the reason behind "earth" being grounded for safe passage of current that has leaked to the equipment's body to the earth. If that is right, then I learn that the "neutral" point is also grounded? If So, then how does the circuit close because I see that for current flow, there must be a closed cicuit. Thus if the domestic live originated from transformer, then say, from my house the neutral must trace its path to the transformer's neutral?

 

[mister_rf]

The neutral is the normal "return" wire. In systems where the load is supplied from only one hot (or "live") wire, the neutral completes the circuit and carries current back from the load to the power station.
All the neutral and ground (or "earth") wires in a building are tied or linked together at the incoming service main breaker panel. This is the only place they should ever be tied together because it is "upstream" of all the fuses and/or circuit breakers protecting the hot (or "live") wires for the various circuits installed in the building.

https://wiki.answers.com/Q/What_is_the_difference_between_three_phase_neutral_and_earth
https://en.wikipedia.org/wiki/Ground_and_neutral

 

[gauthamtechie]

All the neutral and ground (or "earth") wires in a building are tied or linked together at the incoming service main breaker panel. This is the only place they should ever be tied together because it is "upstream" of all the fuses and/or circuit breakers protecting the hot (or "live") wires for the various circuits installed in the building.

What does this mean? Also my question is for a single phase system, so As you've quoted, it does seem that the neutral traces its path to the power station(or in a Delta-star-neutral transformer feeding my home, neutral goes to the neutral of the star connected Low Tension side I assume) . Now my doubt is about the "grounding" of neutral. If the neutral is a return path in single phase, then it also carries current back to close the circuit, and doesn't a ground wire drain it along the way and make it devoid of a closed circuit?

 

[betwixt]

The Earth wire isn't normally connected to anything carrying current at the equipment end so it isn't a parallel connection to the neutral wire. The idea is that in the event of an equipment failure, a high curent may flow along the 'live' to 'neutral' wires and the equipment, being some way along the cables betwen them, may see both wires go to a high potential. The Earth however, is not carrying any current and should stay at a safe low voltage. Although there may be an earth connection back to the power station, there will almost certainly be connections into real ground at other places near the users outlet. The intention is that Earth can be used to provide a safety barrier around equipment so keeping it's potential close to the actual ground voltage beneath your feet, at the users location is important.

Brian.