shower not earthed

[bernardgreen]

If water wasn't conductive then there would be no need to have water proof fittings and IP ratings for water ingress would be redundant.

Maybe pure water is non conductive but tap water is conductive due to additives to ensure it is safe to drink and dissolved minerals from the source of the water.

The dangers of mixing water and electrics are well publicised and yet water is supposed to be non conductive. Can't have it both ways.

Since one cannot safely assume the water is pure one has to assume it is conductive and act accordingly.

 

[Jackrae]

In the old ham radio days a length of wet string made a reasonable aerial - truly "wireless" yet capable of conducting electrons

 

[JohnW2]

If water wasn't conductive then there would be no need to have water proof fittings and IP ratings for water ingress would be redundant.

True.

The dangers of mixing water and electrics are well publicised and yet water is supposed to be non conductive. Can't have it both ways.

Again true - although, to be fair, a lot of the dangers relate to the lower resistance of wet skin, should one touch a live part, rather than to electricity being conducted from the installation to a human being through a column of water in a pipe or hose etc. (or even a 'stream' of water flowing down a wall).

Since one cannot safely assume the water is pure one has to assume it is conductive and act accordingly.

As has been discussed, I can but assume that is the reason we earth showers (something which seems 'intuitively obvious' to do), since I (and seemingly others) can think of no other way in which it could serve a useful purpose.

Kind Regards, John

 

[EFLImpudence]

Interesting.

I suppose my original 'yes' was more due to the thinking of damage caused by earth fault current not being cleared which of course would not happen (the fault not the clearance) if there were no CPC.

In a situation of the water being electrified (especially with a metal hose and rose) where the fault current may not be enough to operate the OPD then the CPC would be acting as bonding to remove any danger.

Therefore the CPC is obviously necessary, although acting as bonding, to prevent a tingle or more but not as far as the shower itself is concerned.

 

[JohnW2]

In the old ham radio days a length of wet string made a reasonable aerial - truly "wireless" yet capable of conducting electrons

True, but the admittance (converse of impedance) at RF is obviously very different from that at 50Hz. One could change that wet string aerial to a long string of very small value capacitors in series and it would still work as an aerial, but would have such a high impedance at 50Hz that it would hardly count as a conductor. However, there is no denying that (impure) water can and does have some conductivity/admittance at 50Hz.

Kind Regards, John

 

[JohnW2]

Interesting. ... I suppose my original 'yes' was more due to the thinking of damage caused by earth fault current not being cleared which of course would not happen (the fault not the clearance) if there were no CPC.

Exactly. I think that's primarily what had BAS and myself (and others) a bit confused by your 'yes'.

In a situation of the water being electrified (especially with a metal hose and rose) where the fault current may not be enough to operate the OPD then the CPC would be acting as bonding to remove any danger.

Perhaps. Although the current would presumably not be enough to operate an OPD, it could be enough to cause an RCD/RCBO to operate - so, since the CPC facilitates operation of a protective device under fault conditions, it might perhaps also be considered as 'earthing. Indeed, if we are regarding the hose/hand-piece (or even the water itself) as an exposed-c-p, then there would presumably be a requirement to earth it?

Therefore the CPC is obviously necessary, although acting as bonding, to prevent a tingle or more but not as far as the shower itself is concerned.

See above - one might argue that it was earthing.

Kind Regards, John

 

[EFLImpudence]

See above - one might argue that it was earthing.

That's true with RCD present.

 

[JohnW2]

See above - one might argue that it was earthing.

That's true with RCD present.

Indeed. Apart from anything else, if that were not the case, no 'earthing' would be possible in a ('pure') TT installation. Of course, current regs require that a shower be RCD protected, and MIs of showers have, AFAIAA, required it for years.

Kind Regards, John