Feeling electricity in water

[deadshort]

Gents, just for the record are you advising the OP that the RCD should not be tested ? Are you also suggesting that if they operate it has no bearing on the situation and of so, what is the purpose of installing RCD's ?

What we are telling you (not merely suggesting) is that pressing the test button on an RCD will (if the RCD is non-faulty) result in its tripping, regardless of any consdierations of earthing, or the absence of it.

The only exception is some RCD sockets, the test buttons of which appear to introduce an L-E leak in order to test RCD functionality. In all other cases (like the RCDs you find in CUs etc.), pressing the button connects a resistor between L on one side of the RCD and N on the other, thereby creating an L-N imbalance which causes the RCD to operate - 'earth', or 'leakage to earth' does not (and could not, in the absence of an earth/CPC connection to the RCD) have anything to do with it.

Of course householders should test RCDs (with the test button) to make sure that they function in response to an L-N imbalance, but that tells us nothing about the presence, absence or quality of an earth. In contrast, an electrician's RCD testing kit usually does introduce an L-CPC leak, and hence will fail to trip the RCD in the absence of an adequate earth.

Kind Regards, John

I must apologies i was thinking of rcbo's with functional earth leads. I agree that an RCD test button does not require a functional earth.

I standby everything else i have said, it is impotant that the OP understands that the rcd will operate in the event of a fault even without an earth.

Regards,

DS

 

[sparkwright]

Please see the installation View media item 87051 View media item 87052 View media item 87053

In the last photograph, I wonder if there's a small slot cut in the metalwork between the two holes where the tails pass through.

 

[JohnW2]

I don't know why this one was bought may be because it will protect all the circuits.the electrician will come back to test everything again and he said tingling in water is caused by lack of earth to the ground as there always small leakage if electricity and it travels anywhere. We had cowboys builders who did a s job.tbe electrician even found live wires behind switches nit fixed to the wall.

Your electrician really should have done tests before he changed the 'fuse box', and he certainly should have done a full set of tests after he had changed it, before he even restored the electricity supply. What he has told you is also a bit strange. Particularly given your past experiences with builders, has this electrician been recommended to you? Would you be prepared to tell us what he is charging you for this work?

Kind Regards, John

 

[333rocky333]

We (at least I) still don't really understand what you mean by "no earth at all to the ground".
Kind Regards, John

Maybe im wrong to assume but
I feel it was the plumber who originally picked up on maybe no supplementary bonding under the bath or no main bonding to the water and gas.
Hence the no earth to ground comments.

The electricians now charged for 20 metres of 10mm and 5 earth clamps I assume to bond the gas, electric, water services.

I now feel by him doing whatever he has put it all at same potential, hence as the Op puts it, stopped the feel of electric in the water

however I do not feel convinced, possibly like yourself, that the initial problem if any has been rectified

 

[JohnW2]

I must apologies i was thinking of rcbo's with functional earth leads. I agree that an RCD test button does not require a functional earth.

AFAIAA, the situation is exactly the same with RCBOs - i.e. the test button creates a L-N imbalance directly ('across the RCD'), and will still result in the RCBO operating even if the functional earth lead is not connected to anything.

I standby everything else i have said ...

I'm not quite sure what 'everything else' you are referring to.

... it is important that the OP understands that the rcd will operate in the event of a fault even without an earth.

I don't really understand that. The only sort of fault in an installation that will cause an RCD to operate is a fault between L (or perhaps N) and an adequate earth. What happens inside an RCD (even in the absence of an adequate earth) in response to pressing the test button is a totally artificial situation which cannot be reproduced by any real-world fault, since that 'fault' has to between the supply and load sides of the RCD.

So, whilst pressing the test button will result in RCD operation even if the installation is totally unearthed, a real-world fault (including current passing through a human being) can only cause an RCD to operate if there is an adequate earth (i.e. an adequate 'alternative return path' back to the neutral of the supply).

Kind Regards, John

 

[deadshort]

Yes, the return path would be her body !

Regards,

DS

 

[Taylortwocities]

I must apologies i was thinking of rcbo's with functional earth leads. I agree that an RCD test button does not require a functional earth.

A couple of points of order. Firstly, if you look at the circuit diagram of an RCBO (with a functional earth connection) you will see that it is exactly the same as an RCD or RCBO that does not have a functional earth (FE). The test circuit provides a LINE>NEUTRAL connection through a resistor to test the trip mechanism of the device.

This then begs the question as to what the FE is for… I must admit that I did not know, but I found the following excellent article that I have pleasure in plagiarising and providing for your illumination|:

1) In order for an RCBO to comply with BS EN 61009, the RCBO does not have to have a separate (functional) earth connection. However, the standard specifies that an RCBO which has a separate earth connection must behave in a certain way to conform to the specification, but the separate earth connection is not mandatory. There are RCBOs currently available that do not have a separate earth connection, yet they achieve full compliance and conformity with the standard.
2) The functional earth is used as reference by the internal RCBO electronics to increase the sensitivity, speed of operation and allows the device to detect an earth fault even if the neutral becomes disconnected. Losing the neutral connection is rare event, especially in TN systems that are increasingly common today. The probability of losing the neutral and having an earth fault at the same time, a double fault condition, is statistically small and evaluated by some manufacturers as so small not be of significance when specifying protection devices. In spite of this, there are those who advocate fitting an RCBO with separate earth connection “just to be on the safe side”. The penalties for this theoretical risk are RCBOs with taller form factors and the extra connection which make consumer units and distribution boards cramped and harder to wire, pushing up required connection time and costs. Even worse some electricians don’t know how to terminate RCBOs and it is quite common to find RCBOs with the functional earth connections cut off, this is clearly bad practice for a device where the electronics relies on a earth reference for its sensitivity and speed of operation.
3) Most manufacturers of RCBOs with functional earth fly-leads insist that these leads must be disconnected during insulation testing to avoid damage to the sensitive electronics, and during earth impedance loop testing to avoid misleading results. A minority of manufacturers insist on the disconnection of the neutral fly-lead during testing in addition to the functional earth, it is therefore important to consult manufacturers instructions before testing. Removing and replacing connections adds to the time and cost of testing, however, there are other issues. First, there is the possibility of failing to reconnect the functional earth fly-lead, leaving the device operating under conditions other than those for which is was designed. Secondly, disconnecting fly-leads goes against one of the basic principles of installation testing, which is that the installation should be tested in the exactly the same state as it will be operated in service. However, we often break this aspiration in installation testing.

 

[londoniese]

This was the old fuse box View media item 87057

 

[JohnW2]

We (at least I) still don't really understand what you mean by "no earth at all to the ground".

Maybe im wrong to assume but I feel it was the plumber who originally picked up on maybe no supplementary bonding under the bath or no main bonding to the water and gas. Hence the no earth to ground comments. The electricians now charged for 20 metres of 10mm and 5 earth clamps I assume to bond the gas, electric, water services.

Maybe - as I said, I'm really not sure.

I now feel by him doing whatever he has put it all at same potential, hence as the Op puts it, stopped the feel of electric in the water ... however I do not feel convinced, possibly like yourself, that the initial problem if any has been rectified

Indeed. We really have no idea what previous potential differences have been eliminated by the (assumed) bonding, and even less idea as to what was causing them. Also, given that the OP observed that the "feeling electricity in the water" was eliminated by wearing insulating footware, suggesting that the pd was between the water and the floor, not between any two things which have been bonded together.

If I were a betting man, I think my money would be on the sensations experienced by the OP having been due to induced voltages with minimal current-supplying capability (hence no hazard), and probably absolutely nothing to do with anything 'wrong' with the installation. That does not, of course, preclude the possibility that appropriate bonding might be able to reduce or eliminate those induced voltages, and hence the sensations.

It does rather seem that the OP has been persuaded that, as a result of what she has experienced, some probably 'not inexpensive' work is necessary.

Kind Regards, John

 

[londoniese]

I don't know why this one was bought may be because it will protect all the circuits.the electrician will come back to test everything again and he said tingling in water is caused by lack of earth to the ground as there always small leakage if electricity and it travels anywhere. We had cowboys builders who did a s job.tbe electrician even found live wires behind switches nit fixed to the wall.

Your electrician really should have done tests before he changed the 'fuse box', and he certainly should have done a full set of tests after he had changed it, before he even restored the electricity supply. What he has told you is also a bit strange. Particularly given your past experiences with builders, has this electrician been recommended to you? Would you be prepared to tell us what he is charging you for this work?

Kind Regards, John

Yes he was recommended, we paid £150 for the day and he is coming back another day test everything in the house for another £150

 

[londoniese]

We (at least I) still don't really understand what you mean by "no earth at all to the ground".

Maybe im wrong to assume but I feel it was the plumber who originally picked up on maybe no supplementary bonding under the bath or no main bonding to the water and gas. Hence the no earth to ground comments. The electricians now charged for 20 metres of 10mm and 5 earth clamps I assume to bond the gas, electric, water services.

Maybe - as I said, I'm really not sure.

I now feel by him doing whatever he has put it all at same potential, hence as the Op puts it, stopped the feel of electric in the water ... however I do not feel convinced, possibly like yourself, that the initial problem if any has been rectified

Indeed. We really have no idea what previous potential differences have been eliminated by the (assumed) bonding, and even less idea as to what was causing them. Also, given that the OP observed that the "feeling electricity in the water" was eliminated by wearing insulating footware, suggesting that the pd was between the water and the floor, not between any two things which have been bonded together.

If I were a betting man, I think my money would be on the sensations experienced by the OP having been due to induced voltages with minimal current-supplying capability (hence no hazard), and probably absolutely nothing to do with anything 'wrong' with the installation. That does not, of course, preclude the possibility that appropriate bonding might be able to reduce or eliminate those induced voltages, and hence the sensations.

It does rather seem that the OP has been persuaded that, as a result of what she has experienced, some probably 'not inexpensive' work is necessary.

Kind Regards, John

no supplementary bonding under the bath or no main bonding to the water and gas.

yes we had none of that but if we looked at the use box we had before it was quite important to sort it out as it looked a mess. I also mentioned before that the soil pipe outside the house is in front of the bathroom, on top of the extension, it was not properly sealed and rain was going underneath bath though there. View media item 87058it is situated in the corner, we cant see well but that where rain goes inside.

 

[JohnW2]

Yes, the return path would be her body

Through her body to where? If the electrical installation (hence its CPCs) were totally devoid of an 'earth' connection (i.e. an alternative return path back to supply neutral) the only way that current could return through a person's body would be via an extraneous-conductive-part (i.e. an 'incidental' path to earth).

Of course, if there are extraneous-c-ps, and they are main bonded to the MET, hence CPCs, then the installation will effectively have an earth, plenty good enough to facilitate RCD operation, even if there is no TN or TT 'earth' connected to the MET. My house is a classic example - a TT earth rod with a Ze of about 75Ω and extraneous-c-ps with a "Ze" of about 0.35Ω ! Once the main bonding is in place, my earth rod obviously becomes a total irrelevance.

Kind Regards, John

 

[londoniese]

We (at least I) still don't really understand what you mean by "no earth at all to the ground".

Maybe im wrong to assume but I feel it was the plumber who originally picked up on maybe no supplementary bonding under the bath or no main bonding to the water and gas. Hence the no earth to ground comments. The electricians now charged for 20 metres of 10mm and 5 earth clamps I assume to bond the gas, electric, water services.

Maybe - as I said, I'm really not sure.

I now feel by him doing whatever he has put it all at same potential, hence as the Op puts it, stopped the feel of electric in the water ... however I do not feel convinced, possibly like yourself, that the initial problem if any has been rectified

Indeed. We really have no idea what previous potential differences have been eliminated by the (assumed) bonding, and even less idea as to what was causing them. Also, given that the OP observed that the "feeling electricity in the water" was eliminated by wearing insulating footware, suggesting that the pd was between the water and the floor, not between any two things which have been bonded together.

If I were a betting man, I think my money would be on the sensations experienced by the OP having been due to induced voltages with minimal current-supplying capability (hence no hazard), and probably absolutely nothing to do with anything 'wrong' with the installation. That does not, of course, preclude the possibility that appropriate bonding might be able to reduce or eliminate those induced voltages, and hence the sensations.

It does rather seem that the OP has been persuaded that, as a result of what she has experienced, some probably 'not inexpensive' work is necessary.

Kind Regards, John

You are saying

If I were a betting man, I think my money would be on the sensations experienced by the OP having been due to induced voltages with minimal current-supplying capability (hence no hazard), and probably absolutely nothing to do with anything 'wrong' with the installation. That does not, of course, preclude the possibility that appropriate bonding might be able to reduce or eliminate those induced voltages, and hence the sensations.

It does rather seem that the OP has been persuaded that, as a result of what she has experienced, some probably 'not inexpensive' work is necessary.

so are you saying it was not a major problem? then how do we get rid of it and how do you explain that the bonding stopped it?
also you said the problem was between he floor and the water because when wearing crocks I could not feel anything , but the tiles were no wet at all, so how would my feet would be a conductor only when touching the water, and why would not feel anything just by walking on the tiles and not opening the taps?

 

[JohnW2]

A couple of points of order. Firstly, if you look at the circuit diagram of an RCBO (with a functional earth connection) you will see that it is exactly the same as an RCD or RCBO that does not have a functional earth (FE). The test circuit provides a LINE>NEUTRAL connection through a resistor to test the trip mechanism of the device.

Thanks for confirming. As I said, that was my understanding - so, unfortunately for him, DS's understanding was still wrong even in relation to RCBOs.

This then begs the question as to what the FE is for… I must admit that I did not know, but I found the following excellent article that I have pleasure in plagiarising and providing for your illumination|: ...

Yes, I'm familiar with that explanation about the purpose of FEs, and it sounds like a reasonable argument/explanation. What I've never understood is why the concept of FEs seems to be restricted to RCBOs. At first sight, exactly the same considerations exist in relation to RCDs but I have never seen or heard of an RCD with a FE (although maybe they exist?). Do you have any explanation for this?

Kind Regards, John

 

[JohnW2]

You are saying ...

If I were a betting man, I think my money would be on the sensations experienced by the OP having been due to induced voltages with minimal current-supplying capability (hence no hazard), and probably absolutely nothing to do with anything 'wrong' with the installation. That does not, of course, preclude the possibility that appropriate bonding might be able to reduce or eliminate those induced voltages, and hence the sensations. It does rather seem that the OP has been persuaded that, as a result of what she has experienced, some probably 'not inexpensive' work is necessary.

so are you saying it was not a major problem?

We obviously don't know - but I'm saying that, if I were a betting man, then, yes, my money would probably be on it not having been a 'major problem'. However, given that we can't be certain that it was not a major problem (i.e. potentially dangerous) one would obviously want to have it checked out, not gamble on 'gut feelings'

... then how do we get rid of it and how do you explain that the bonding stopped it?

Well, you say you have got rid of it, so you know the answer to the first question. As for the second part, as I wrote "That does not, of course, preclude the possibility that appropriate bonding might be able to reduce or eliminate those induced voltages, and hence the sensations.". In other words, even if the sensations you experienced were not indicative of a 'major (i.e. potentially dangerous) problem', appropriate bonding might well get rid of them. I suppose an analogy would be to the various measures (in many ways analogous to 'bonding') that people take to avoid getting static shocks off things - those static shocks would never have done them any harm, but the 'measures' can nevertheless get rid of them.

However, as everyone has said, from the very start of this thread, the correct and sensible approach had to be to get an electrician to check out your electrical installation, since there was always the possibility that something potentially very dangerous was going on. Whether or not any appropriate tests have yet been done, I'm not so sure - from what you have said, it sounds that they may not have been.

KInd Regards, John