Why does standing on the earth complete a circuit

[lordyjordy1]

Hi

My understanding of electrics is that you need a complete circuit for electrons to flow.

eg: from a battery cell the electron will flow through a wire to say a lamp and then through another wire back to the battery thus completing the circuit

However, say my washing machine is faulty and the metal casing has become live. I then touch the metal casing whilst standing barefoot on the floor.

I understand that by doing this I would get a shock as electrons would pass through me into the ground- but why??

how does the circuit complete itself simply by me standing on the ground??

 

[EFLImpudence]

Because the ground is the second wire in your example.

It completes the circuit back to the transformer (battery) hence the terms - ground and earth. It just does.

 

[matt1e]

basically because neutral and earth are connected together on the supply side
you therefore complete the circuit from live (or line as its now called) to neutral via your body and earth

 

[Heinz57]

You would get a shock because the electrons are looking for the quickest way to ground, which in the case of this would be you.

That is why alot of apliences come with an earth connection. Should the live or neutral break. Or present some problem, or make a metal part of the appliences casing come live, the earth connection sort of 'shorts it out' and quickly takes the current to earth, stopping any harm in coming to you.

Some appliences like drills and other power tools don't have an earth connection, these are double insulates appliences. This means that there is two layers of insulated plastic protection between you and the electrical bits and peices inside. Of course these carry exposed metal parts, but these are not connected in any way to the electrical bits and peices inside, the double plastic insulation also protects these exposed metal parts from becoming live.

 

[ricicle]

double insulates appliences. .

At least get the terminology correct before posting

 

[cumbriahandyman]

double insulates appliences. .

At least get the terminology correct before posting

If the reader knows what is being said, who cares (in this case) about the correct terminology.

 

[ban-all-sheds]

It's not incorrect terminology.

Just dreadful spelling, careless typing, and no proof-reading.

 

[aptsys]

You would get a shock because the electrons are looking for the quickest way to ground,

Are they?

 

[holmslaw]

..

 

[FDJ]

Some appliences like drills and other power tools don't have an earth connection, these are double insulates appliences. This means that there is two layers of insulated plastic protection between you and the electrical bits and peices inside. Of course these carry exposed metal parts, but these are not connected in any way to the electrical bits and peices inside, the double plastic insulation also protects these exposed metal parts from becoming live.

Try telling that to my Erbauer mitre saw in which all the metalwork became live and gave me a hell of a belt yesterday.....
Class II is all well and good but when things go wrong???
Frank

 

[Heinz57]

@ricicle - That should read 'insulated'. Its just a slight type error. Nothing to write home about.

@aptsys - Yes. Electrons look for the quickest, easyest or shortest path to ground/earth. They don't care whats conducting them, so long as it can carry them.

@Frank - Things can and do go wrong and the metal work can become live. In a ClassII applience, the exposed metal work should not be connected in any way to the live electrics within. That is not to say that sometimes things don't go wrong and the metal work can become live.
That is why I think the best method of protection would be to give some appliences both double insulated and earthed protection. There are many arguments to say this isn't required. And it may well be a fact. That is just my own opinion

EDIT - Fixed type error

 

[Taylortwocities]

@ricicle - That should read 'insulated'. Its just a slight type error. Nothing to write home about.

@aptsys - Yes. Electrons look for the quickest, easyest or shortest path to ground/earth. They don't care whats conducting them, so long as it can carry them.

@Frank - Things can and do go wrong and the metal work can become live. In a ClassII applience, the exposed metal work should not be connected in any way to the live electrics within. That is not to say that sometimes things don't go wrong and the metal work can become live.
That is why I think the best method of protection would be to give some appliences both double insulated and earthed protection. There are many arguments to say this isn't required. And it may well be a fact. That is just my own opinion

EDIT - Fixed type error

Wrong again, beansman.

Double insulated, class II appliAnces must never be earthed. They will be supplied with a flexible lead that only have live and neutral conductors. How, and where would you plan to earth the appliAnce?


PS what is the meaning of the @ character?

 

[aptsys]

@aptsys - Yes. Electrons look for the quickest, easyest or shortest path to ground/earth. They don't care whats conducting them, so long as it can carry them.

Which way do electrons flow in an AC circuit?

 

[Alarm]

@aptsys - Yes. Electrons look for the quickest, easyest or shortest path to ground/earth. They don't care whats conducting them, so long as it can carry them.

Which way do electrons flow in an AC circuit?

In a DC Circuit the electron flow is from negative to positive, that is absolute. In an AC Circuit the electrons 'wiggle' or vibrate back and forth but the energy goes forward.
ie. think of a wave pool, and a rubber ducky going up and down on the wave. The rubber ducky is the electron. At the end of the pool the energy is emitted.

Does this help?

Awaits a slaughtering

 

[Heinz57]

Wrong again, beansman.

Double insulated, class II appliAnces must never be earthed. They will be supplied with a flexible lead that only have live and neutral conductors. How, and where would you plan to earth the appliAnce?


PS what is the meaning of the @ character?

That is indeed correct. Look again at my post to where I said 'it is a fact', and where I said 'my own opinion'.

I am fully aware that double insulated appliances don't carry and don't require an earth connection. I was simply offering my view on the subject.

The '@' character? Ahh, that is just a quick method of replying to (multiple) people, without quoting them, that I've picked up from other forums and sites etc


@Aptsys, you tell me. The clue is in the name, alternating current

*Ducks for cover *