Low Earth Voltage in bathroom from bonded fittings

[Octopus]

Cheers Murdoch, my sparky has tested from the earth bond under the sink in kitchen back to CU and it was fine with wander lead and megger

So not at the areas you are concerned about then ..

 

[Kris Dor]

Cheers Murdoch - Im sure this will be next on the list when my sparky comes back. If not I'll mention it to him. I don't suppose there is anything I can do to check this? I'm not going to mess around in the CU so I guess I'll have to leave that idea until he comes back.

 

[Kris Dor]

Sorry Wilko - in answer to your question it seems to be pretty constant 0.2v and 2v unless I run the shower when it increases. If I run it then stop it then run it again it is cumulative but the subsequent rises are not as high as the first which goes from 2 to 12v, the second might get it from 12-14v the third 1v extra then it seems to top out.

 

[Risteard]

my sparky says Im TNS. I'm told that the setup will be that the earth is taken from the Neutral

That would be TN-C-S - not TN-S.

 

[Midwest]

Thanks so far for the interest,

Midwest I don't want to bond the shower frame - I'm using it as a 0v to measure the others in the absence of 100m of earth cable and a spade in the garden - I appreciate this is haphazard but I can feel a tingle from the showerhose and sometimes the rad too, never anything from the shower frame.

Your shower frame, it is just a piece of metal, it is not connected to the general mass of earth, unless the fixings screws are really long!

Same goes for the radiator. Some things may require bonding, such as the pipes feeding the radiator. You will need to have a logical approach to this problem, and rule out the obvious to start with, best done by an electrician.

And I'm not suggesting your imaging things, but checking 'voltage' with a multi meter is meaningless, but that's not to say there isn't a fault.

As an example, whilst doing a bathroom refurbishment a few years back, the plumber was a getting a shock when he was touched the walls and pipes. It transpired, the previous owner had put up some dado rail on the landing, and nailed a cable for the landing light, making the wall nice & live.

 

[Kris Dor]

Good call Risteard - yes, the earth is going into and out of the box with the 100A rather than tagged onto the cable before the fuse.

 

[Kris Dor]

Cheers for the reply Midwest - I'll have a think about nails, I did put a piece of chipboard down in the loft, I'll make sure I haven't nipped or crushed a cable up there.

 

[Midwest]

Don't be offended Kris, but if you are experiencing 'tingles', think its time you asked a competent electrician to carry out some tests on your installation, perhaps even an electrical installation condition report (EICR), don't know what the other members think about that suggestion?

 

[Octopus]

I had to investigate something like this a couple of years ago. I found that that shower cubicle was live

 

[Kris Dor]

I've had two Part P registered sparkies round already and booked in for next week hopefully to do some more testing. Unfortunately it's not something I can instantly achieve - seems to be a busy time round here - there is a massive amount of housing being built so I'm just waiting in line - I appreciate your sentiment though Midwest - I'm just seeing what i can do on the home owner front while I'm waiting.

 

[Midwest]

I appreciate your sentiment though Midwest - I'm just seeing what i can do on the home owner front while I'm waiting.

I'd stop using the offending item, and wait and see.

 

[Pete999]

I've had two Part P registered sparkies round already and booked in for next week hopefully to do some more testing. Unfortunately it's not something I can instantly achieve - seems to be a busy time round here - there is a massive amount of housing being built so I'm just waiting in line - I appreciate your sentiment though Midwest - I'm just seeing what i can do on the home owner front while I'm waiting.

Kris
You mentioned that you have had 3 "Part P Electricians" (quite what a Part P electrician is I'm not sure) around already, what did they actually do? and did the find anything wrong with your electrical installation?

 

[Sparkie30]

A clamp meter might help aswell.

 

[Des 56]

I've had two Part P registered sparkies round already and booked in for next week hopefully to do some more testing

Checking on a individuals testing and fault finding competence, perhaps via qualification,it would be a better precaution than gauging someones testing abilities by them being on that Part P register

 

[mhar]

The water outlet from the pump to the shower will be in plastic, therefore the shower not extraneous conductive. Is the radiator extraneous and conductive or is there any plastic plumbing? If you are connecting non extraneous parts via some form of bond, any voltage on the earth cable will be introduced to these parts. You already implied that there is something on the earth as there was a little spark when it was disconnected from cu.
Are you not making non extraneous conductive parts into extraneous ones and then wondering why there is a voltage on them?
Clamp the earth, find the earth leakage and go from there