shorting neutral to earth confusion

ElectroPhysics

what will happen if i short neutral ac outlet wire with earth? please see the figure if you have any confusion.

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davenn

neutral and earth are usually connected at the house entry buss board anyway

Dave

OldEngr63

The answer is nothing, provided that everything was properly wired and that the power source generator was grounded. This covers most cases, but certainly not all of them.

With a Y-connected generator, it is easy to ground the center of the generator, and it is common practice to do so. With a delta-connected generator, there is no center point, and consequently such systems often have not grounded neutral (the happens in the US Navy in places).

If in doubt, measure the potential between the two wires before you short them.

nsaspook

With a ground to neutral connection at more than one place (at the main power panel) on a normal house AC system the risk of the ground connection becoming a current carrying connection increases. The voltage difference between ground and neutral might be several volts at a distant power plug on a circuit that draws significant current (due to voltage drops from line resistance). If the connection is made at the distant device a GFCI device will trip due the unsafe condition if you are lucky. High currents passing in grounding circuits can be dangerous because they are designed to handle fault currents that only last a short time and are not normally current carrying conductors.

http://en.wikipedia.org/wiki/Residual-current_device

NascentOxygen

Sometimes neutral and active get swapped around, accidently, as can happen when someone makes up their own extension cord, or replaces a broken plug, etc., and in the process gets the wiring reversed through carelessness. Many appliances [seem to] operate satisfactorily despite this, though they can be an electrical hazard to the user.

You can picture the scene were you to unknowingly connect the lead marked "neutral" to ground in the event of it being one of those botched wiring jobs.