Supplementary bonding

[EFLImpudence]

M1Chanical -

Earthing is not a good thing in its own right.

It is a necessary evil to cause disconnection of the supply, by the fuse/MCB before you touch them, should parts of electrical equipment become live.

It would be better if no parts needed earthing.

 

[JohnW2]

Where did that come from?

I suspect it's a prelude to bernard claiming that supplementary bonding in bathrooms is desirable (even when 'not required') - don't forget ('floating') metal baths!

Kind Regards, John

 

[ban-all-sheds]

If your bath is floating then you've got a major plumbing emergency on your hands...

 

[JohnW2]

Is the pipe not earthed by the boiler CPC?

Are you talking about my neighbour's oil pipe. If so, as you imply, it very probably is earthed by the boiler. However, I need not tell you that IF it were deemed to require main bonding, then its earthing via CPCs would probably not be adequate as bonding (either in terms of conductor CSA or location).

I would think an insulating section in the pipe would be a better solution.

Probably, but there isn't one.

What would you do in places that don't flood so regularly?

'Flooding' was perhaps an over-statement - 0.5cm water on a patio isn't that unusual. Anyway, if the pipe were nowhere near the ground, then I would not regard bonding as necessary.

You know that I essentially agree with all that you're saying. I probably over-reacted last night to being somewhat irritated by the fact that the OP was being taken to task over terminology when he had actually asked about (and entitled the thread about) supplementary bonding - which was totally correct. The fact that his friend had asked about 'earthing' is really neither here nor there - the OP translated that into correct terminology when posting here.

Kind Regards, John

 

[bernardgreen]

Where did that come from?

Just a question about the reliability of the CPC to the shower. Should one put all one's trust the CPC to remain effective when "bonding " the exposed pipe to another item that was "earthed" would create a back up "earth" path should the CPC to the shower fail.

 

[EFLImpudence]

If so, as you imply, it very probably is earthed by the boiler. However, I need not tell you that IF it were deemed to require main bonding, then its earthing via CPCs would probably not be adequate as bonding (either in terms of conductor CSA or location).

No, but conversely, if it is earthed by the boiler CPC then it doesn't matter if it is bonded unnecessarily (second earth).

 

[EFLImpudence]

Just a question about the reliability of the CPC to the shower. Should one put all one's trust the CPC to remain effective when "bonding " the exposed pipe to another item that was "earthed" would create a back up "earth" path should the CPC to the shower fail.

That's nothing to do with bonding and a very strange concept - supplementary earthing.

If you consider the pipe 'exposed' as in 'exposed-conductive-part' then you should earth it (connect to CPC).

If not, then it is obviously not an extraneous-conductive-part so must not be earthed (bonded wrongly) .

 

[ban-all-sheds]

An electric kiln ( 8 kW ? ) is supported by exposed metal legs. No bonding to the exposed metal legs.

Is it safe to rely on the CPC in the cable supplying electrical power to the kiln?

 

[ban-all-sheds]

That's nothing to do with bonding and a very strange concept - supplementary earthing.

If you consider the pipe 'exposed' as in 'exposed-conductive-part' then you should earth it (connect to CPC).

If not, then it is obviously not an extraneous-conductive-part so must not be earthed (bonded wrongly) .

Is Bernard's day job Being David Cockburn?

 

[JohnW2]

That's nothing to do with bonding and a very strange concept - supplementary earthing.

Strange under that name, although "CPC redundancy" is a non-strange concept we often discuss - in relation to ring final circuits and, sometimes 'high integrity earthing'. However, I agree that it's nothing to do with bonding in the usual sense - bernard seems to be talking about connecting ('bonding') something which is already earthed to something else which is also earthed, thereby creating the redundancy/'backup' of connections to earth.

Kind Regards, John

 

[JohnW2]

Is Bernard's day job Being David Cockburn?

I think he's just very 'risk-averse', which is a not uncommon part of the spectrum of 'utility'.

Given that earthing has an important safety-related function and that the user of an installation will obviously be unaware of a failure of a single CPC, I suppose one can understand some people feeling that it is desirable that one should have belt as well as braces, even if the risks in question are undoubtedly exceedingly small.

Kind Regards, John

 

[EFLImpudence]

Strange under that name, although "CPC redundancy" is a non-strange concept we often discuss - in relation to ring final circuits and, sometimes 'high integrity earthing'. However, I agree that it's nothing to do with bonding in the usual sense - bernard seems to be talking about connecting ('bonding') something which is already earthed to something else which is also earthed, thereby creating the redundancy/'backup' of connections to earth.

One wouldn't (mustn't) use an isolated part to achieve it.

 

[JohnW2]

One wouldn't (mustn't) use an isolated part to achieve it.

I can't see how one could, since if you mean 'electrically isolated', it would not have a primary CPC, so one could not add a second 'redundant' path to earth.

Kind Regards, John

 

[JohnW2]

No, but conversely, if it is earthed by the boiler CPC then it doesn't matter if it is bonded unnecessarily (second earth).

Indeed - but I don't think anyone has suggested that it would 'matter', have they?

Kind Regards, John

 

[EFLImpudence]

I can't see how one could, since if you mean 'electrically isolated', it would not have a primary CPC, so one could not add a second 'redundant' path to earth.

I think Bernard was wanting to join his "exposed" pipe (which I don't think should be earthed or bonded) to another to create a second earth path.

Just a question about the reliability of the CPC to the shower. Should one put all one's trust the CPC to remain effective when "bonding " the exposed pipe to another item that was "earthed" would create a back up "earth" path should the CPC to the shower fail.