In a battery, the current flows from – to +.
In a house it runs from the phase to the neutral wire.
However, if you touch the phase wire while making contact with the ground, the current will flow through your body to the ground, ie you will be electrocuted. With a battery you can touch the + pole without the current starting to flow to the ground, because the circuit is not closed.
How is it possible that current flows from phase to ground?
Answer
Hi Jan,
For safety reasons, the neutral wire in the power plant and transformer cabins is connected to earth (earth). As a result, it is always known what voltage the cables have in relation to the earth. If you do not do this, you will not know what the status of the grid is, because then it is possible, for example, that your neighbor has a contact between a phase and the earth due to a fault/short circuit in an appliance. At that moment the grid is no longer ‘floating’, and current can flow through the earth again. That is why it has been decided to always hang the neutral wire to earth.
In small limited installations it is sometimes possible to work without a connection to earth for safety reasons. An example of this are the connections for hydrogen vacuum cleaners in swimming pools. These are connected to transformers where the secondary winding provides normal mains voltage, but where the neutral wire is not connected to earth.
Sincerely,
Luc
Answered by
ir Luc Bosmans
Technology in the audiovisual sector
Industrial quay 170 B-1070 Brussels
http://www.erasmushogeschool.be/
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