Electric shocks from earthed appliances.


When ever I touch the earthed part of an appliance with a sensitive area of skin (the underside of my wrist) I can feel a slight tingle of electricity, similar to putting a 9v battery on your tongue.
This only happens if I am downstairs, in bare feet, standing on the quarry tiled floor.
The problem is less if I unplug everything in the house. plugging in a few power supplies (mobile, router etc) that sit on the floor, makes the problem worse.
There is a connected earth rod into the ground by the side of the house.
Any ideas? (and yes I know the problem is dangerous and needs sorting:-) )
Adrian Smith
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I would suggest that your earth rod has a higher than specified resistance to earth, causing a voltage above ground potential to exist on your protective circuit. You could try to give the ground a good soaking around the earth rod to see if this makes any difference.

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Someone else has just suggested that to me.
If the earth is non existent or a bad connection like you suggest. Would it be possible for there to be a voltage between the circuits earth and the ground?
Adrian Smith.
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You just reminded me of when in the army, on exercise various trucks like the machinery wagon and the generator trailers had an earth spike driven into the ground. Normal squaddie procedure was to piss on it regularly. To ensure a good earth of course.
This might not endear you to your neighbours though.
Steve
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What sort of supply do you have?
http://www.diyfaq.org.uk/electrical/electrical.html#system
should help you as will the uk.d-i-y newsgroup if you can get it on your server.
Just because you have an earth rod does not mean you have a TT supply. It may now be a PME supply that has not had the earth connected because the bonding in the house is not suitable for a PME supply. A few photos of you cutout (fuse) and your fusebox may help you find a solution.
Adam
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Adrian. Appologies for not getting back to you sooner, yes I would say that some of your connected appliances have slight leakages to earth. Under normal circumstances an "efficient" earth must have a minimal resistance to the surrounding earth. Perhaps in your case that resistance is of a higher than acceptable level. One way of checking this would be to connect a volt meter between the connection at the top of the earth spike and a known good earth. Any reading displayed on the meter would indicate that any stray voltages are finding it easier to take the route via the meter to the lower resistance good earth. It may only read 50-75 volts, but this is enough for that tingling feeling under the right conditions. Should this be the case, it is your local suppliers responsibility to provide you with an earth connection that meets the laid down specification. Regards Len.

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Thanks for the reply.
I'm going to do some investigation with a multimeter.
The house is in France, so I am not sure if the electric company are duty bound to provide an earth.
Adrian Smith

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Ummm, very doubtful. A friend of mine had a villa built in Spain several years ago, and he said it was impossible to isolate any of the live circuits using any of the MCB's in the consumer unit. On investigation we found that the whole place was wired with the MCB's in the neutral of each circuit. It would have been simple to just reverse the incoming cables at the consumer unit, but all the circuit wiring colours would have to be reversed as well.
Len.

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<< Reorganised so not top posted >>

In Europe (excluding UK), isn't the standard that all individual electrical devices (such as kettles, etc) have both poles switched (not sure of the correct expression, it's when the switch on the appliance isolates both +ve and -ve when switched, unlike here where only the +ve is isolated).
Therefore it doesn't matter to them which way round the incoming is wired as any CBs should switch both?
Richard Web pages: http://www.caravanningnow.co.uk/ - caravanning, http://www.rcole.org/ - personal web site and http://www.homeindorset.co.uk because I loves the domain name for email.
--
... people could tell that Foul Old Ron was approaching by the way their ear
wax started to melt. - \'Soul Music\' by Terry Pratchett
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Richard. We checked, that was not the case. all the light switches were single pole and so were the MCB's. So even with the MCB's tripped out, the circuit was still live in respect to earth which is a dangerous situation. My friend found this out whilst he was putting up some new light fittings. Also being that most electric shocks received are of the live to earth variety, that wiring practice cannot be acceptable anywhere in the world. Regards. Len.

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