Earthing a water pipe??

[JohnW2]

Weak Earth or Strong Earth. and RCD operation

What you say is all very true, but I don't really understand its relevance to this discussion.

Kind Regards, John

 

[ban-all-sheds]

As things stand, with Class I appliances in existance and (other) earthed things around in a substantial proportion of buildings, I would think that the risk resulting from not earthing (Class I) appliances would be much greater than the risk resulting from earthing them.

I don't think that earthing, or not, of electrical appliances or parts of an electrical installation and earthing, or not, of things which are not electrical appliances or parts of an electrical installation can follow the same rules.

 

[JohnW2]

I don't think that earthing, or not, of electrical appliances or parts of an electrical installation and earthing, or not, of things which are not electrical appliances or parts of an electrical installation can follow the same rules.

I don't think anyone has suggested that they can, BUT the answer to the question of whether or not parts of the electrical installation (including appliances) should be earthed is crucially dependent upon whether the environment contains earthed items which are not electrical items or parts of an electrical installation.

If you are suggesting that earthed exposed parts which are not electrical appliances or parts of an electric installation cannot be prevented by 'rules' then it is almost certain that exposed conductive parts of "non-Class II" appliances must continue to be earthed.

Kind Regards, John

 

[JohnW2]

Edit - responding to John's not remembering the details. I didn't realise there was another page.

Another page of what? The CPS document linked to appears to only have one page.

Kind Regards, John

 

[bernardgreen]

What you say is all very true, but I don't really understand its relevance to this discussion.

A plastic pipe to a metal radiator creates a weak earth on the radiator. A person holding a Live ( faulty ) item who then touches the radiator would get a mild shock. They would probably break one of the contacts before the shock became non survivable. But if they did not, could not, break the contac they would continue to receive a mild shock, possible long enough to become non survivable.

The relevance is that there is a case for converting weak earths into strong earths ( by adding a CPC ) to try and ensure that the RCD operates before the shock becomes non survivable.

Door handles and teaspoons are ( hopefully ) never going have a weak earth, items connected by plastic pipes with chemically laden water to an Earthd boiler do have waek earths.

 

[EFLImpudence]

Quite apart from the technicality that has been mentioned by others, I'm not really sure what you are saying.

I mean In the case quoted,

whether one touches live studwork and earthed pipe or live appliance and earthed studwork.

One cannot guard against both at the same time .

 

[John D v2.0]

I mean In the case quoted,

whether one touches live studwork and earthed pipe or live appliance and earthed studwork.

One cannot guard against both at the same time .

You can guard against both, but indeed not by changing the bonding, but by making the studwork non conductive eg timber.

 

[EFLImpudence]

Another page of what? The CPS document linked to appears to only have one page.

Oh come on, I replied to your comment without realising there was another page of posts.

I think you are more intent on replying to everything without always taking time to fully understand what has been written.

 

[ban-all-sheds]

One cannot guard against both at the same time .

 

[EFLImpudence]

You can guard against both, but indeed not by changing the bonding, but by making the studwork non conductive eg timber.

It would not be bonding. It would be earthing isolated parts - the metal studwork.

Yes, wooden studs would remove the problem but they may catch fire.

 

[aptsys]

What CPC?

As I said, such a hypothetical situation would remove the need for CPCs and, even if they still existed in an installation's wiring, they would not be connected to anything outside of the building.

Kind Regards, John

All sockets would need an isolating transformer for this to be effective. You would only need a fault in another property running from the same transformer to eliminate the two fault protection that a floating system provides.

 

[JohnW2]

I mean In the case quoted, whether one touches live studwork and earthed pipe or live appliance and earthed studwork. One cannot guard against both at the same time .

That's exactly my point - one can only guard against one or the other, so that the decision whether or not one would regard earthing the studwork as desirable depends upon one's judgement as to which of the two possible scenarios is the more likely.

In this case, there is at least some criticism of the fact that the studwork was not earthed (and was not required to be earthed). However, had the incident resulted from 'the other scenario', I presume that some people might have been criticising the fact that it was earthed.

Kind Regards, John

 

[JohnW2]

Oh come on, I replied to your comment without realising there was another page of posts. I think you are more intent on replying to everything without always taking time to fully understand what has been written.

That's not fair!

I said that I couldn't remember all the details, the reason being that the CPS document which had been linked to did not contain many details. In response, you wrote:

Edit - responding to John's not remembering the details. I didn't realise there was another page.

Can you really blame me for thinking that you were suggesting that I had missed a second page of the CPS document??

Kind Regards, John

 

[John D v2.0]

It would not be bonding. It would be earthing isolated parts - the metal studwork.

Yes, wooden studs would remove the problem but they may catch fire.

True it would be earthing, but still it wouldn't help.

Doubt timber would catch fire without another combustion source, you'd need a few thousand kv to get enough current flowing to cause them to burn! And you'd have enough smoke to let you know not to touch the fire.

 

[JohnW2]

All sockets would need an isolating transformer for this to be effective. You would only need a fault in another property running from the same transformer to eliminate the two fault protection that a floating system provides.

Are you perhaps considering the possibility of a fault to an extraneous-c-p affecting other properties which also have extraneous-c-ps?

Kind Regards, John