12 volts reading from bathroom taps

[clive.jackson]

Help - I am trying to trace why I am getting a fluctuating 9-12 volt reading across the taps in my bathroom in my house in Spain.

Background The house is over 20 yrs old. The wiring looks Heath Robinson. Recently had swimming pool lights re-connected and bulbs replaced...

Symptoms - lighting circuit flickers, circuit trips. Existing water immersion heater (3.5kw) is spurred of the lighting circuit Guest received a shock from the taps in the bathroom When tested showing up to 56 volts Possibility that the house earth grounding was severed during work carried out at the time the pool lights were supposedly fixed.

Actions Additional earth stake put in ohm's reading dropped significantly, but not yet at the right levels Taps now reading 9-12 volts

Recommendation Use a new electrician to re-wire the dodgy circuits

Questions Going out this weekend, what can I do to test and try and isolate the problem? I am a novice so some reading (the guide to testing electrical domestic installations) and advice would be most appreciated.

Thanks Jacko

[meow2222]

56v from where to where? tap to earth or tap to other tap?

The source of the 56v will be mains 230v, with current limited by presumably faulty insulation (given the shock). IOW it could fry someone at any time.

That would certainly fit the picture. But given that your heater is on the light circuit, there is mains power on the taps, and the taps arent bonded anywhere, the whole system sounds like a disaster. If it were mine I'd check the whole lot out and sort it, as it stands its just plain dangerous. IOW your problem is bigger than 1 or 2 symptoms.

what resistance reading?

for now anyway

Well, you need to test everything, it sounds very screwed and entirely unsafe.

The most immedate fault could be found by sticking your voltmeter on the taps, switching all circuits off at the CU, and turning them on one by one. When one causes your taps to go live, switch it off and leave it off until fixed, with warning notice.

But dont kid yourself this will make it safe, all that would do is find the biggest most immediate danger. You still have unearthed taps with no effective leakage protection, and by the sound of it some other horrors. The only thing I could advise doing is switch the power off to the whole house and leave it off.

You've got a pool as well, gawd.

NT

[cynic]

Get a copy of the on site guide to BS7671 and STUDY it thoroughly. I agree with NT the whole system needs properly investigating and maybe a full rewire is called for. If you get back to Blighty several training organisations offer courses of about two weeks duration where the basic knowledge (and building regs for electricians) can be obtained. It sounds as though that might be a useful course of action for you.

[jacko3288]

Thanks NT

Re the tap reading - I was "told" tap to earth - but want to check when I get out there

Re the earth stake reading, I am not sure but wanted to know if I can get hold of some test equipment today and whethe rit's worth it as I have found some "more professional" electricians

Actions - was planning to do as suggested, shup every thing down and bring them back one by one with a volt meter on the taps. Next step is a fully re-wire!

[jacko3288]

Thanks for the tip - will get hold of a copy from Amazon...but in the mean time I was looking for something I could download. Need to get up to speed for when I meet the Spanish electrician.

[Clive Mitchell]

In message , [e-mail] writes

Why were they disconnected in the first place. Are they submerged mains lights? Consider changing them to low voltage before somebody experiences water borne voltage gradient.

[Graham]

Reminds me of my first holday abroad, in La Escala. There was a part of the hotel swimming pool where you could feel a servere tingle, that was 40 years ago, I wonder if they ever fixed it.

[meow2222]

You should be able to find whats going on with nothing more than a multimeter and a lightbulb. If you want more kit, you could use it, but those things would generally be adequate to find the serious problems.

Re a rewire, you'll probably find much of the wiring is either ok or only needs minor work on it, so its not like it all needs replacing, but it will all need going over, some does need replacing, and there will be a fair bit of minor rewiring to make it all safe.

If you want to do some yourself,

a) you'll soon know which circuit is electrifying the taps, and using a multimeter measuring R from circuit L to the taps you can find out where the leakage is, and replace the leaky item.

b) you need to see where earthing is failing. Check R from earth block at CU to local earth (metal stake in ground), then check R from that earth block to the taps. Most likely there is a disconnection in one of those 2 areas. If not, and everything's connected, then you lack RCDs on the CU and need them. Local earthing is not an effectrive way to clear earth faults, hence RCDs are required for local earths.

c) you need to bond all the mains services at their entrances to the house to CU earth block. This means water, gas, oil, etc.

d) rewire the supply to the water heater, running it off the lighting is, well, crackers. Then change the lighting fuse/mcb to 5A or 6A.

Doing those should solve all the evident problems, but you still need to get it all checked out, especially as youve got a pool and therefore presumably shower (scary).

Warning & disclaimer: you need to know what youre doing before doing each job. If not competent, leave it alone, let the system fry you instead.

Until done I'd stay well clear of pool & shower. Isolate any supplies to them, with warning notices.

NT

[Clive Mitchell]

In message , Graham writes

Maybe it was a feature.

The tingling pool of invigoration.

[Jim Ingram]

The article on kevin boone site gives a reasonable description of how a household electrical system should work.

's not perfect but the details of spanish regs might well be different anyway.

Jim

[Andy Hall]

Always remembering that the further away from the poles you go, the less the correlation between regulation and practice.

For example, traffic lights in Italy, Spain, Portugal, Greece are more of a guideline than anything else.

The Spanish word for a private security guard is "vigilante"; the English meaning being someone taking the law into their own hands.

There is probably a similar comparison for electrical installation inspector.

A sobre marrón will generally help though.

[John Anderton]

If the re-wire doesn't help, it might also be worth checking out the immersion heater element. If the element has corroded through, you could have mains voltage in contact with your hot water inside the tank.

One other symptom I had when this happened to me was the top half of the tank getting hot but not the bottom half as the element was corroded through halfway down but obviously that varies depending on how far down the corrosion is,

Cheers,

John

[cynic]

The intent of earthing is to provide a path for fault currents to flow with two aims - 1 to cause the circuit protective device to operate and cut off the power and 2 to hold down any voltage rise to a safe value near to earth potential. A damaged immersion sheath should not cause the problem described if the earthing is adequate. From description so far it sounds as though the protective device is not suitably rated, the earth loop impedance is too high and the wiring has been installed by an incompetent. I could do with a holiday in Spain!

[R]

*That* is NOT good

It's Spain.....and in rural areas vary in "expertise" of wiring and also quality of anything else to do with construction. (DAMHIKIJD)

First suspicion is earthing through the pool lighting feed. Shut down the power, disconnect it, reapply the power, and take another reading from the taps using a meter. DON'T touch the metal surfaces while you do so though....Obviously.

What may have happened here is a "better" route to earth for the existing faulty supply giving the live area problems a lesser reading.

Call the local authorities (Council) and ask for a certified or approved electrician to attend.

at Questions

You might start here

read with lots of links at he bottom providing a good insight and more info. Watch out for the Pop-ups

[Andrew Mawson]

replaced...

another

approved

or

insight and

I get concerned with sites like that when they contain statements like:

"The frequency of DC voltage is 50 or 60 Hz depending on the country"

AWEM

[Lurch]

On Sat, 7 Apr 2007 09:48:29 +0100, "Andrew Mawson" mused:

And "Why did the US choose 120v for household current".

That page looks awful, I could probably read it if they split the one stupidly long page into several smaller pages. Some people shouldn't be allowed near websites.

[John Anderton]

Agreed. I was thinking of the symptom of the lighting circuit tripping. If the wiring is re-done (including proper earthing) and the circuit (presumably not the lighting one after things are done properly !) still trips, a corroded immersion heater could be the culprit,

Me too !

Cheers,

John

[R]

I *did* mention it was a long read...