Electric shock in bathroom

[BobHoughton]

Hi,
I have recently moved into a house and the bathroom (downstairs) is a wet room with shower. However sometimes after a shower I can feel a buzz/vibration from the shower taps and sink.

The boiler is a combi boiler and is situated just outside the bathroom. I have had a engineer check the boiler as the problem only happens after the boiler has been on a couple of mins. He could not find a problem and of course I could not reproduce the fault when he was at the house.

The confusing thing is that it only happens in the bathroom. The kitchen, which is next to the bathroom does not have this problem.

The water pipes and radiator in the bathroom have the earth connectors on. The shower pipes are all in the wall so I can not check these.

I am at a loss now as to how to solve the problem. I do not think that the voltage is very high to couse this vibration/buzz when touching any metalic obect, but it is still a worry.

Does anyone have any ideas as to how to trace/solve this fault.

Thanks in advance.

 

[JohnD]

It is possible that you only notice it when your skin is wet, and you are standing, with wet feet, without shoes, on a wet floor. So the fault might still exist in other parts of the house.

Your best action would be to ask around friends and neighbours for a well-recommended professional electrician who appears to use modern tools and practices. My preference would be to choose one who is a member of a self-certification scheme though others can be equally good.

In the meantime, have a look at your consumer unit (fuseboard). You are looking in particular for green-and-yellow sheathed earthwires, nearly as thick as a pencil, coming out of the service head by the meter and going into the consumer unit; and for another wire, nearly as thick, going to the incoming water main, and one to the gas pipe. There might be a label fixed next to the meter saying "Protective Multiple Earth" (but other earthing methods are acceptable).

Also look in the CU for an RCD, which is like the main switch but has a "test" button on it.

Then look in the bathroom. You should find similar earth wires, but not as thick, connected to the hot and cold pipes, the radiators, and the shower, and also going to the lighting circuit (this may be connected in the ceiling) and the shower switch.

You should also find that all the pipes going in and out of the boiler are bonded using similar G&Y wire with the same kind of bright metal pipe clamps.

If any of these things are missing, as they might be with an old or inexpert installation, your electrical installation needs upgrading. Electrical faults in the bathroom are very dangerous. You would do best not to use the wet rooms with the shocks until it has been tested and rectified. The fault need not be a complicated one.

How old is your house and your electrical installation?

 

[BobHoughton]

The house was built in 1924 but the bathroom is relativley new, about 5-6 years old.

I only have the cold water pipe earthed. Is there a way of checking the earth wire is actually connected to the fuse box?

 

[JohnD]

******I only have the cold water pipe earthed*******

***** This is a really, really bad sign. *****

Is there a way of checking the earth wire is actually connected to the fuse box?

Describe your fuse box, please - Make, size, colour (really), does it have fuses or circuit breakers, what do they look like.

If you can lay your hands on a digital camera and put up a pic, that would be great.

Preferably showing the meter, fusebox, service head and the wires around them.

 

[BobHoughton]

OK I will get the info tonight.

What I can say is it is dark brown in colour and has circuit breakers for 3 zones, upstairs, living room and kitchen/bathroom/extrnal shed.

Thanks.

 

[JohnD]

OK, thanks. I'll wager that it is a Wylex Standard in brown bakelite with a wooden sub-frame at the back.

It is almost certainly due for replacement - probably only a 60Amp main switch; terminals too small for 16mm earths, exposed live brass links on internal switch. About 40 years old no provision for an RCD and fiddly to add an external one, undersized for an electric shower or big cooker....

Time to start looking for a good local electrician, I fear.

Supplementary bonding in the bathroom can be done first.

 

[BobHoughton]

Thanks for your help.

I'll start looking for a good electrician now.

Thanks again for your help.

 

[BobHoughton]

One last question.

What is "supplimentry bonding"?

 

[JohnD]

Supplementary bonding:

In a bathroom, the objective is to ensure that all the bits of metal you might touch that could introduce a voltage, are all attached together so that there can be no voltage difference between them. So if you touch e.g, the shower with one hand, and the radiator with the other, you will not get a shock between them. This is achieved by bonding all* the metalwork and the earth conductors of all the circuits in the room.

It sounds to me as if, at the moment, there is a voltage difference betweeen the bathroom floor (and perhaps some water pipes) and the shower.

This is different from main earthing which also needs doing.



(but not e.g. a brass coat hook on the back of the door that isn't attached to any other conductor)

 

[securespark]

Your best action would be to ask around friends and neighbours and get them to do the same