Earth Bonding In A Bathroom

[frank11]

Hi Electricans,
I am a homeowner with an earth bonding question I am receiving conflicting advice upon and hoping someone can help point me in the right direction.

A few years ago I had a full bathroom replacement via my insurance company and a bathroom installation company they supplied.
Earlier this year on a Thursday evening a bath was left on an overflowed for a few minutes or so.
On the following Sunday evening my wife got an electric shock when handling the taps in the sink, I worked out that if I turned the ground floor hallway light off the shocks stopped so I taped off the light switch so the light wasn't turned back on.
I called out a qualified electrician who was able to attend on the Thursday, by that time the offending water must have dried out as there was no longer any shocks coming from the tap but he carried out a number of tests which involved running cables from my fuseboard to the bathroom and concluded that the pipework running to the taps were missing an earth bond as plastic connectors had been used (which were added by the plumber who installed the bathroom a few years back) so from his testing he said beneath the plastic connectors his tests show a 'good' earth bond but above the plastic connectors there isn't an earth bond - I have included an image of the pipework beneath my sink so you can see the layout.

The electrician said that to remedy the situation I would need an earth bond adding from beneath the plastic connector to above the plastic connector which is relatively easy for him to do.
The problem is he has stated the same problem applied to the bath taps which don't have an earth bond either so is assuming plastic connectors were also used on the piping to the bath taps.

There is a difficulty in the fact the bathroom fitter fitted a full tiled side to the bath instead of a bath panel so to access the pipework to the bath taps I need to rip off the tiles which form the bath panel and also then need to replace the side of the bath again.

I contacted the insurance company who have been in touch with the bathroom fitter who has disputed the electricians view that his plastic connectors are the cause of the problem and after I suggested to the insurance company that they appoint an independent electrician to provide a report (which I would pay for initially and to be refunded if their electrician said the lack of earth bonds are a problem) and they then said if I get quotes for the work they will get it sanctioned and cover the cost.

The electrician who initially pointed towards the need for earth bonds indicated a price of £140 for him to add earth bonds in but I had to find someone to quote to take off the 'bath panel' tiling and then replace it after the electrician has done his work. I have now contacted 2 separate bathroom fitters and on explaining the above background they don't agree that the earth bonds are needed so I am left wondering what to think.


Could any of you guide me as to whether these earth bonds are needed as although the taps do not give electric shocks now my worry is that an unseen leak occurs somewhere, connects the pipework to a live electrical connection somewhere and my 9 year old lad gets an electric shock.

So very long winded but thought it good to let you know all the info.

 

[bill01803]

Can you post a pic of the distribution board

 

[James]

Was there any electrical work done when the bathroom was fitted?

If so, was a certificate supplied?

 

[ChrisElectrical88]

I gave up reading as soon as I read an electrician wants to install supplementary bonding in a bathroom, we’re not in the early naughtys now. Get us a picture of the mains board, with the cover on will be fine.
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I’m going to guess every circuit apart from the downstairs lighting has 30mA RCD protection.

 

[snowhead]

There's a bit of the investigation missing from all this.

In order to have got a shock there needs to have been a source of power involved not just a lack of bonding.

Either the taps and pipework became live as a result of the bath overflowing in which case somewhere above the plastic fittings and I note there are 2 more closer to the taps, there was contact between a live cable through the water to the pipe.

Alternately I supect there's a nail or screw through a live cable in the floor and there is enough of an earth through the non bonded pipes to have caused a shock.

Is the floor tiled?
Was your Wife touching anything else as well as the tap?

 

[ChrisElectrical88]

There's a bit of the investigation missing from all this.

In order to have got a shock there needs to have been a source of power involved not just a lack of bonding.

Either the taps and pipework became live as a result of the bath overflowing in which case somewhere above the plastic fittings and I note there are 2 more closer to the taps, there was contact between a live cable through the water to the pipe.

Alternately I supect there's a nail or screw through a live cable in the floor and there is enough of an earth through the non bonded pipes to have caused a shock.

Is the floor tiled?
Was your Wife touching anything else as well as the tap?

You can get a voltage through those plastic push in plumbing connectors. Got to be under the floor for me.

 

[James]

Could be wet floor, wet joists, direct path to light fitting below through wet timber and debris in ceiling void.

 

[snowhead]

Could be wet floor, wet joists, direct path to light fitting below through wet timber and debris in ceiling void.

Agree.
And what it's not is absence of bonding.
In fact if the bonding was put in place and the same event happened again it could make the situation worse.

Having read the O.P again, it could be a cable / connection under the bath that the water made contact with.
And reading again, the answer is in the O.P, it's the switchwire for the downstairs light or connection at the light

 

[ChrisElectrical88]

I’ve read it in full now, I agree with James.
I think the wet floor has tracked to the hallway light and then in turn touching the taps has provided a path back to earth through you. I like to think when they have done the bathroom that they added additional protection to the bathroom circuits but not the downstairs lights as there would be no need. 30mA RCD protection to the hallway light would have prevented this.
however I await to be told I’m wrong ?

 

[frank11]

There was no electrical work done when the new bathroom was fitted

 

[Vortigern]

Do you have underfloor heating?

 

[frank11]

No underfloor heating.

Appreciate all your comments and guidance.

I'm not too concerned to find out where the offending section is where the issue was created when I had the leak as its now dried out (and I don't plan on having a leak) but more looking to find out whether having an earth bond would stop the taps getting live/producing an electric shock if there were a leak in the future.

 

[ChrisElectrical88]

Get a EICR mate

 

[Vortigern]

I am not sure you could get a shock through two plastic connectors, and some damp wood. But anyway looking at your electrics, if you are concerned about safety etc. I suggest you upgrade your fusebox to a modern one with RCD protection as soon as possible. As an aside did you have a wet floor and bare feet when experiencing these shocks? I also wonder, when the bath actually leaked on Thursday, did no one else get a shock from the taps? Is it only you that got a shock some three days later? Were you touching both taps?

 

[Strima]

As alluded to by others there could be a more serious problem which was only highlighted when things became wet.

It appears you have no RCD protection, an RCD would have more than likely have tripped as soon as the fault occurred, not when your wife touched the taps.

Did your electrician do any further inspection and testing or did he/she go straight to the pipes and suggest bonding?

 

[littlespark]

Plastic push fit connections are used widespread, We don’t link every bit of copper pipe nowadays.

the electrician that quoted to bond the pipes is having a go.

Unless he links every length of pipe every side of every fitting, which could, in the event of another fault, create live taps across the house!

upgrade your consumer unit, which would involve the EICR suggested, will pick up any nailed cables and would increase the safety of your installation.

 

[frank11]

I am not sure you could get a shock through two plastic connectors, and some damp wood. But anyway looking at your electrics, if you are concerned about safety etc. I suggest you upgrade your fusebox to a modern one with RCD protection as soon as possible. As an aside did you have a wet floor and bare feet when experiencing these shocks? I also wonder, when the bath actually leaked on Thursday, did no one else get a shock from the taps? Is it only you that got a shock some three days later? Were you touching both taps?

No wet floor (can't remember about bare feet)
No one got a shock until Sunday night but I worked out you only got a shock if the hallway light was on so maybe Friday and Saturday we happened to not use the taps when the light was on.
The shock happened if you only touched 1 tap

 

[Wilko]

Hi Frank, for what it’s worth I agree with above posts - this incident was likely not caused by Mr Plumber using plastic fittings. After water leaks on the top floor it’s quite common for the downstairs lights to be affected.

The pic of your fuse box worries me as it seems to show a switch or junction box floating about?

 

[Vortigern]

junction box floating about

Energy meter.
Hey @frank11 what about an upgrade if you want safety though?

 

[snowhead]

Appreciate all your comments and guidance.

I'm not too concerned to find out where the offending section is where the issue was created when I had the leak as its now dried out (and I don't plan on having a leak) but more looking to find out whether having an earth bond would stop the taps getting live/producing an electric shock if there were a leak in the future.

It's ESSENTIAL that the source of the problem be found, whether it's a fault of the bathroom refit or pre-existing.
You can never know if you're going to have a leak and exactly the same conditions occour.

Having an RCD on the lighting circuit won't remove the issue, it's still possible to get a non lethal but uncomfortable shock without tripping an RCD.
Testing may not find the issue if it's a screw or nail only touching the Live.
Hopefully whoever you get in won't give up untill they've found the source of the problem.

If I was looking into it I'd use an Endoscope /Boroscope camera to look up into the floor through where the hall light is fixed, to avoid any unneccesary damage initially to see if there is anything obvious.
Next would be remove the bath panel and look under there.

 

[telectrix]

skimmed through but agree with preceding posts. copper pipes under sink and bath, if preceded by plastic, are not extraneous and should not be bonded. the sparks who suggested this should be taken out and shot in the goolies, then sent on a course to understand the purpose of bonding. it seems you have an underlying fault which manifested iteself due to a water leak. sack both electrician and plumber, and then get an expert in each field to fix.

 

[freddo]

I'm not too concerned to find out where the offending section is where the issue was created when I had the leak as its now dried out

I'm reasonably confident if Emma Shaw was still alive she would be less than pleased to hear that comment.

 

[James]

It is entirely possible that there is no fault with the electrics, a ceiling rose could be wired with no permanent live, even if it has a permanent live, the switched live is normally on the outside of the rose.

Any water creeping into the rose is likely to contact the switched live far before the permanent live. Tracking back through the wet woodwork in the house until it finds a path to earth.

If there is an rcd supplying the circuit, the path to earth through the timber and back to earth via multiple paths is going to trip the rcd well before any risk of shock occurs.

The simple fact is, the system installed because of its age is unable to detect the type of fault that occurred.

Modern rcd’s Or rcbo’s would have turned off the power, probably before the shock risk was there, but certainly the moment a shock was felt the power would be switched off as the device would trip in less than 0.03 seconds (less than a blink of an eye to the layman)

 

[Midwest]

No wet floor (can't remember about bare feet)
No one got a shock until Sunday night but I worked out you only got a shock if the hallway light was on so maybe Friday and Saturday we happened to not use the taps when the light was on.
The shock happened if you only touched 1 tap

I had something not too dissimilar, a story I’ve recanted here many times. Long story, shortened. Complete bathroom refurb. Plumber was getting shocks when touching copper pipes and newly plastered wall. All walls in vicinity of bathroom had voltage to earth. Sometimes rcd would trip. Turns out previous owner had installed some dado rail on the landing years previously, with nail just nicking cable (stripper) to landing light.

As already said, get a competent electrician in to do some testing.

 

[ChrisElectrical88]

I'm reasonably confident if Emma Shaw was still alive she would be less than pleased to hear that comment.

Awful read that ?. Wonder if that was a factor in RCDs to all circuits Buried less than 50mm in the building fabric coming in not long after? Shows the importance of IR testing.

 

[telectrix]

Awful read that ?. Wonder if that was a factor in RCDs to all circuits Buried less than 50mm in the building fabric coming in not long after? Shows the importance of IR testing.

but that wouldnot have identified the fault as the metal rack was fitted after the installation had been completed., and the fault was not there before.

 

[nicebutdim]

but that wouldnot have identified the fault as the metal rack was fitted after the installation had been completed., and the fault was not there before.

That was a different case - the linked story involved cable damage at the time of construction, which had subsequently been certified as safe.

 

[telectrix]

That was a different case - the linked story involved cable damage at the time of construction, which had subsequently been certified as safe.

mybad. mixed up the 2. however, in the emma case, it seems that the fault was from cable to encosed metal stud that was not earthed/bonded. so a IR test would not pick it up.

 

[Intoelectrics]

My advice, as per other posts, get a proper electrician in to do an EICR and mention also the problem you experienced during the flood. Installing supplementary bonding will not solve the issue, (and as stated, may potentially make it more dangerous) the fault will still remain.
Speculating on what or not what it could be is no help to you. Over the years Most of us experienced sparks have come across similar faults before , (I know I have) and the faults have been identified as the same or similar to each of all the above mentioned so far, so yours could be anyone of them or something entirely different.

I would also recommend a consumer unit upgrade, modern consumer unit devices offer much better protection.

 

[freddo]

however, in the emma case, it seems that the fault was from cable to encosed metal stud that was not earthed/bonded. so a IR test would not pick it up.

Indeed, even if you carefully followed every detail in guidance note 3 the defect would go unnoticed.