Why sometimes neutral wire gives shock, what's the problem of the wiring ?

[dineshdeshmuk]

Why sometimes neutral wire gives shock, what's the problem of the wiring ?

thanks

 

[thannara123]

There haven't proper earth connection (neutralization at the junction may fault in the transformer )

 

[mvs sarma]

Why sometimes neutral wire gives shock, what's the problem of the wiring ?thanks

Hope your doubt is on the mains supply and not after some circuitry has been added, like a diode bridge .

The power distribution transformers, have the neutral wire grounded there. But as the supply is extended over metalic feeder wires, the same neutral wire would have return current as seen at user homes.
this current multiplied by the wire resistance causes voltage drop with ref to ground.
This Voltage is higher , the farther you are located.

Secondly, if the connections at intermediate feeder branches are loose, they offer more resistance and the voltage drop increases.
If this drop increase beyond a substantial voltage, it gives shock

 

[vimalkhanna]

Actually , the problem exists in the 3ph balancing at the load point .
The 400V 3ph /50Hz on the feeders may be loaded differently on the three phases .
The neutral shifts as the third phase with lesser loading and output voltage wrt neutral increases.
Many times I have lit up a 12VDC car parking lamp between my ground earth and neutral..

 

[polo-g40]

can you measure the voltage? If its half mains voltage, its because there are 2 capacitors, one from live to earth, one from neutral to earth... If the earth isn't there in the middle, then you can get 110v (half 240) on the neutral line (and the outer of many AC to DC converters) becuase they act as a potential divider... There is little driving current behind the voltage (the capacitors will be at large impedance at such low frequencies) but can be noticeable when working with stripped wires because if one breaks the skin slightly it makes me jump!!!
NEAL

---------- Post added at 16:38 ---------- Previous post was at 16:37 ----------

There wil always be a small ammount of voltage accross neutral and earth because of the volt drop in the wiring for the neutral, but I've not managed to light more than an LED

 

[mvs sarma]

@vimalkhanna,
i agree with your observation after analysis. I stand corrected and thank you Khanna jee.