Thanks for the reply, but I disagree as no matter how much government legislate people will still do stupid things. If I injure myself then I have no one else to blame other than myself. Did the introduction of building regulations stop unsafe construction?
This is one of the main problems with modern society in that its never your fault. For example people who are in serious debt or purchased property and are now in negative equity blame the banks or property programmes for their problems and never themselves.
He is getting the shock when *touching the switch* and something earthed, be that the tap or the metal toaster.
No, I don't believe there is a fault with the wiring or toaster. Just a lot of grunge around/in the switch. Have you never had shock/tingle from a switch when you have wet hands or from a dirty switch?
Changed a light switch in a bakery office last week. Full of crud & s*1t. So old, the metric screws wouldn't thread, had to reuse the originals - what were they, BA or something? Any idea of when the change was made?
I'm staggered by this thread that I have watched from inception. I honestly thought that you were trolling. MBQ and Dave L gave you good advice. What stopped you isolating the assumed circuit in the first instance? Then check that the live source was eliminated and replace the socket if the wiring behind it was sound? Then reconnect and cautiously check using a meter and glo screwdriver to check before plugging anything in? If you do not understand these comments, you should have called someone in immediately. You put your family at risk.
20 to 25 years ago, I was given a 3.5 mm tap for back boxes, so sorry, I can't answer the question of when the change took place IYSWIM. But I think that the screws were so similar that they would have been interchangeable. Electricians on this ng will confirm.
Part P seems to have resulted in an *increase* in accidents and fatalities (as many of us predicted). So aside from adding cost, complexity, and bureaucracy to stuff it has hand no effect in eliminating natural selection!
Not really... It suggests the toaster is connected to the earth terminal in the socket but not much more that that conclusively. There are two basic ways you could get a shock between tap and toaster - either the tap is live, or the toaster is.
If the toaster is live then we also have to assume it is not earthed, since if it were this would 1) limit the touch voltage on the case[1], and 2) hopefully cause enough fault current to flow to blow the fuse.
[1] perhaps not enough to eliminate the shock, but the magnitude should be less when compared with the switch touching episode. That would suggest the switch has a conductive path to earth rather than live then.
If the tap is live, and the earth on the toaster is good, you would not get any fault current on the toaster circuit and the fuse would remain ok. That would then suggest the main equipotential bond to the water pipes is missing or high impedance.
You may also have more than one fault - say high impedance earth on the circuit or socket.
To be honest, no never. However, regarding the fault - yup the switch tracking to live may give the results seen, but its not the only way.
So you are prepared to put yourself, and your family, at risk because rather than call in a professional? There are probably other things wrong just waiting to kill somebody.
OK, isolate the circuit as you have done. Unplug everything from it. If there are any fixed appliances connected to it, then turn them off with their isolator switches.
1) First test, visual inspection; take the socket off the wall, and check the wires are in the correct places, and correctly inserted in the terminals and the insulation is undamaged, the screw terminals are tight. Check the earth wires are sleeved.
2) With a multimeter on its highest ohms range, measure the resistance between earth and live on the socket terminals. It should show an open circuit.
3) Measure between live and neutral. Again it should be open circuit.
4) Measure between live and the place on the switch that you touched. Again, open circuit.
5) Measure between earth and switch, and again expect an open circuit.
6) Now with the meter on its lowest ohms range, measure between earth and neutral - you should get a low reading - under an ohm.
7) Now measure between earth and tap, you should also get a low reading (assuming you have metal plumbing to the tap).
A failure of 1 alone, or 2, 3, and 6 suggest a circuit wiring fault that needs further investigation. The article mentioned before covers the next steps (i.e. checking ring continuity at the consumer unit, and an insulation resistance check)
A failure of 4 or 5 above suggests you must replace the socket. (Although I would replace the socket anyway). Note however that these are not conclusive, since if there were a high resistance path to live, you may not see it at the low volts the multimeter tests at. If you have access to an insulation resistance tester, then that might show a fault that is otherwise not visible.
A failure of 7 suggests further investigation, depending on your plumbing etc.
Once thing to bear in mind, is that the process of inspecting etc can actually alter the results - for example a poor connection can become good just by moving the socket on its wires etc.
Now assuming all of the above pass, don't just pile back in and assume everything is ok - take a cautious step by step approach. First check the connection between the toasters earth pin and its case (low ohms range - should be near enough zero). Between live pin and earth (high ohms range - open circuit).
leave everything else disconnected, but plug the toaster in and switch it on at the socket.
*** Make sure there is no one who might go near it while testing ***.
Replace the fuse and use the multimeter on a 250V or higher voltage range to measure between case and tap. You should see near enough nothing.
I swapped an old Volex socket front last week. It was supplied with 4 screws when new. The 4BA screws were still attached to the back of the socket and the 3.5M screws had been used. The sizes of the screws were labelled on the back of the socket.
Assumung that the socket was put on when the house was built I would say that the socket was 45 to 50 years old.
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