why we can't connect Null line to device body instead of earth

[baby_1]

Hello
as you know we use the earth wire to protected human and device.i want to know why we not use Null wire instead of earth wire?
what is advantages and disadvantages?

 

[FvM]

For an overview of earthing systems see https://en.wikipedia.org/wiki/Protective_earth

In my view, you don't need much engineering knowledge to understand why TN-C (neutral used as common return and protective earth) is very unsafe. Just consider a broken neutral wire.

 

[goldsmith]

Hi jetek
What answer ? see the link that FvM attached . it is pretty good .