Le_Jars Posted June 2, 2008 Share Posted June 2, 2008 Sometimes when I put my hand on my dishwasher or washing machine I get a small electric shock. How is this possible? they are both plugged into the same double socket, which I have had apart and can see nothing missing/in the wrong place. Should I be looking elsewhere? Is it dangerous? The plugs on both machines are the moulded type and are both very new. Any ideas? Thanks. Link to comment Share on other sites More sharing options...
Clair Posted June 2, 2008 Share Posted June 2, 2008 Bad earth?No earth? Link to comment Share on other sites More sharing options...
Dick Smith Posted June 2, 2008 Share Posted June 2, 2008 [quote user="Le_Jars"]Sometimes when I put my hand on my dishwasher or washing machine I get a small electric shock. How is this possible? they are both plugged into the same double socket, which I have had apart and can see nothing missing/in the wrong place. Should I be looking elsewhere? Is it dangerous? The plugs on both machines are the moulded type and are both very new. Any ideas? Thanks.[/quote]We once had precisely this problem with a dishwasher. It turned out that case was resting on the power cable and the vibrations had worn it through, so that there was current leakage.Or, as said, it could be a dodgy earth in the socket. Link to comment Share on other sites More sharing options...
Mutiara Posted June 2, 2008 Share Posted June 2, 2008 I agree with the others that it is likely to be a poor (or lack of) earth to the socket; or possibly a fault or break down of insulation on the machine itself. Firstly get the socket checked out to see if the earth is connected and efficient. I would also make sure that the whole installation is protected by a interrupteur differentielle rated at 30 miiliamp trip current. Older installations don't often have this trip and it is essential that you get these two things checked out. Link to comment Share on other sites More sharing options...
La Guerriere Posted June 2, 2008 Share Posted June 2, 2008 Seconded. Electricity and water make very uncomfortable bedfellows. Link to comment Share on other sites More sharing options...
sid Posted June 2, 2008 Share Posted June 2, 2008 Thirded!! [;-)]We had this same problem and it was due to a poor earth. We have since had the whole electrical system upgraded!! Sid Link to comment Share on other sites More sharing options...
powerdesal Posted June 2, 2008 Share Posted June 2, 2008 Sometimes when I put my hand on my dishwasher or washing machine I geta small electric shock. How is this possible? they are both pluggedinto the same double socket, which I have had apart and can see nothingmissing/in the wrong place. Almost certainly a bad / missing earth, not necessarily in the wiring in the socket (which you have checked)Should I be looking elsewhere? Yes, check the other sockets in your house, they all go to the same earth Is itdangerous? The plugs on both machines are the moulded type and are bothvery new. Yes.Use an earth tester on every socket and work back from the results.If the house is old and has not been rewired I would suspect NO MAIN EARTH.I found exactly the same on my house, which is why it now has a new earth spike driven in 1.5m and properly wired to the earth bar in a new tableau. Link to comment Share on other sites More sharing options...
Clair Posted June 2, 2008 Share Posted June 2, 2008 [quote user="powerdesal"]If the house is old and has not been rewired I would suspect NO MAIN EARTH.I found exactly the same on my house, which is why it now has a new earth spike driven in 1.5m and properly wired to the earth bar in a new tableau.[/quote]Same thing here, that's why I suggested it. Link to comment Share on other sites More sharing options...
Mutiara Posted June 2, 2008 Share Posted June 2, 2008 Just to add something about earthing if I may. An earth spike just hammered into the ground will not necessarily mean a good earth. The only way to know if the main earth is good is to measure it with a proprietary earth tester. The resistance of the main earth rod should be no more than 100 ohms for an installation (protected by an EDF main disjoncteur with a trip current of 500 milliamps). This is the Consuel minimum pass limit. Unless you have very good soil conditions, you are unlikely to get an earth resistance this high with a 1m rod ( the most common size sold in all the brico's). You will either need to use a 2 metre rod or use two or more rods ( distance apart should be at least 1 rods length). Link to comment Share on other sites More sharing options...
La Guerriere Posted June 2, 2008 Share Posted June 2, 2008 Mutiara is 100% correct. We are in Normandy and its permanently damp. Our 1.5 m rod just about about does it. But its still a damn sight better than a bit of wire stuck hopefully in the ground, or even worse nothing at all. While you are waiting for the electrician to come and a) give you a devis b) come and do the necessary, treat yourself to as big an earth rod as you can get (sounds a bit saucy but whatever), bang it in, and hook up to the earth terminal on your sockets. This does not conform with the norms but it might save lives while you are waiting.... Link to comment Share on other sites More sharing options...
Le_Jars Posted June 3, 2008 Author Share Posted June 3, 2008 As far as I know, all the other sockets and appliances are fine as the place was re-wired a couple of years ago. Could it be that just this socket has a loose earth? Could I somehow link an earth wire to a nearby socket that does have a good earth? (does that make sense?). Link to comment Share on other sites More sharing options...
thunderhorse Posted June 3, 2008 Share Posted June 3, 2008 No reason why you can't daisy-chain a suitable earth.Could one of the knowledgeable explain how a dodgy earth (or no earth) in a socket seemingly allows current leakage to the body of an appliance? If there is a dodgy earth and someone is getting little belts from an appliance, then clearly there is more at fault than just a dodgy earth. Link to comment Share on other sites More sharing options...
trees 2 Posted June 3, 2008 Share Posted June 3, 2008 I've had the same, (well, the wife has, I'm blowed if I could feel it, even wet handed and touching water pipes with the other hand[:P]).Anyway, testing with my trusty multimeter revealed 70VAC between neutral and earth.[:'(]The socket LOOKED OK and had an earth.However, when I traced IT'S wiring back further, I found a poor set of connections in a tiny scruffy junction box, and sure enough, a VERY small wear on one of the cables inside it. Also, the "earth" only went as far as that j/b and it's end was neatly clipped off inside.I isolated the whole lot, and ran a new supply, WITH proper earth, direct from the tableau. Link to comment Share on other sites More sharing options...
Jerac Posted June 3, 2008 Share Posted June 3, 2008 I once spent ages looking for the leakage in a toaster which gave a small shock from its metal body. Eventually I discovered that the double socket that it was plugged into had a fault on the earth connection. The source of the shock was not the toaster but a freezer plugged into the same socket and leaking some voltage to earth, which was finding its way via the earth connections to the toaster.The leakage probably comes from interference suppressors fitted inside some appliances with motors. Capacitors connect between the supply neutral and phase and earth and remove the transient spikes that cause interference. These capacitors will leak a very small current to earth. Normally this dissipates to earth harmlessly, and is too small to bother the 30ma differential. If there is no earth then this small leakage will appear as a voltage strong enough for some people to feel.If it is the case that the installation has earth connections to all sockets, but there is not a proper connection to an adequate earth, then the real danger is if appliance develops a full blown phase to earth short . Not only will the casing of that appliance become live, but that leak will travel through all the interconnected earths to other appliances making them live as well. If the installation is modern and protected by 30ma differentials then as soon as the leaked current starts to travel through the unfortunate that has touched it the differential will trip, but if there is no differential then the consequences would probably be fatal. Link to comment Share on other sites More sharing options...
JohnRoss Posted June 3, 2008 Share Posted June 3, 2008 I notice that our property, and several others I have seen, has a metal link between the consumer unit and the earth mat or rod. This link is held by two nuts and can obviously be removed for some purpose. Removing the link would isolate the earth device, rod or mat, I assume to enable some sort of test. What sort of test would that be? I can only assume that this test is something that would need to be done from time to time and not just when the house was wired originally otherwise why would this facility be fitted in the first place, any clues?.............................JR Link to comment Share on other sites More sharing options...
La Guerriere Posted June 3, 2008 Share Posted June 3, 2008 Yup, the link (barette de terre) is removable so that the earth impedance can be measured using a special ohmeter de terre Link to comment Share on other sites More sharing options...
JohnRoss Posted June 3, 2008 Share Posted June 3, 2008 Thanks, I have tried to find out what an earth loop test is. A quick look at the net has shown lots of info on earth loop testing boxes and earth impedance testers but no info on how it is done, any pointers. Could a Megga be used for this and if so how and how does removing the link come into this?.............................................JR Link to comment Share on other sites More sharing options...
Le_Jars Posted June 4, 2008 Author Share Posted June 4, 2008 Well, I did piggy back a connection from another plug and that seems to have done the trick; no sign of any shock anywhere at all now. Thank you all for your advice. :) Link to comment Share on other sites More sharing options...
Phil & Pat Posted June 5, 2008 Share Posted June 5, 2008 [quote user="trees 2"]Anyway, testing with my trusty multimeter revealed 70VAC between neutral and earth.[:'(][/quote]I seem to recall from a long while ago that the French use an impedance-grounded neutral system (unlike the UK). Is this still the case? Link to comment Share on other sites More sharing options...
Recommended Posts
Please sign in to comment
You will be able to leave a comment after signing in
Sign In Now