electric shock

[geoffr]

Just had a strong jolt when I turned on a double socket when at the same time I was touching a tap in the kitchen. The tap is a combined hot and cold one. I tried the adjacent socket and another double socket which is also close enough to the kitchen tap to touch both but they were fine. I then tried the probem socket again and got the same jolt. If it's relevant I was wearing a "croc" type shoe.

My electrical tester is broken so I had to rely on an electric screw driver tester with a neon light. This lit up when in contact with the socket switch, so assume its a fault with the socket switch.

However, what concerns me is how can you protect yourself from this as the jolt was fairly strong for an adult, it could be more serious for a child.

Also, does it indicate a fault with the electrics in the house? The kitchen is on a separate old fashioned consumer unit with wired fuses and no RCD protection, while the rest of the ground floor is wired via a modern consumer unit with an RCD and MCBs. The electrics had been tested 2 or 3 years ago and as far as I am aware the metal work is properly bonded.

Any advice would be gratefully received.

Geoff

[Andy Dingley]

Frequently fatal. This sort of shock (touching a good earth when you're already at an elevated potential) is one of the few that kills people in practice. Newsreader's daughter from a couple of years ago? Many people put up with "that switch that always gives you a tingle" for an incredibly long time, then get killed by it on the day they're walking barefoot across the spilled water or similar.

You have at least two faults here, both serious enough to be "pull the fuses and fix immediately".

Firstly your socket faceplate is live. Bad.

Secondly your socket faceplate isn't earthed, via a good low-impedance earth path. Assuming that fault #1 arises in the nature of wear & tear, then this should have been sufficient to send a fault current back through that earth and pop the fuse, thus isolating(sic) the circuit.

I'd regard #2 as serious here (#1 obviously is) because although poor earths are endemic in old installations, it sounds here as if you have a metal-fronted socket which I'd guess was more recent and really should be earthed properly.

[John Whitworth]

So you got a shock straight through the chest/heart (i.e. finger-arm-chest-arm-finger) and you went back for more???!!!

Seriously - if you have these problems with your electrics, and you don't know what could be causing it, turn off at the CU, and get a sparky round fast!

JW

[geoffrob16]

Thanks Andy and John for your replies.

The face plate is a standard MK plastic one and its only the switch which is lighting the screw driver. I know these screw drivers aren't accurate but is it possible that the short in the switch it too far aware from the earth connector to send a fault current to trip the fuse?

Although, it's an old fashioned fuse box the actual wiring is relatively recent and in good condition. When it was tested a couple of years ago the earth loop impendance reading was 0.3 ohm from one of the kitchen sockects. I have also checked the earth connectors in the socket, in the kitchen fuse box and the connector to the house itself and they are all tight, although I do understand that without a proper tester you cant be sure there is not a fault elsewhere. The kitchen sockets are connected in a ring.

As a further test I plugged in the toaster to the socket and instead of touching the tap when I turned on the switch I touched the metal side of the toaster and I had the same shock. Therefore doesnt this imply that the earth wiring is OK as there would not have been a circuit for the current to travel down if there was a problem with the earth.

I appreciate the risks but before I do call in a professional could it simply be a faulty socket switch?

[Man at B&Q]

You're either a bloody fool or a troll!

MBQ

[Jim]

That's a bit like looking for a gas leak using a match - please stop testing for earthing by using yourself as a meter!

Finding the root cause is not as simple as leaping to conclusions.

[Dave Liquorice]

Easy enough to pop out get a new one and replace it.

I suspect wet/grease/wear/accumulated gunk has produced a leakage path from the live terminal to the surface of the switch. Is someone in the household in the habit of wiping down the sockets with a damp/wet cloth with or without any cleaning agent?

[RobertL]

Especially, asthe OP seems to be doing, touching with both hands (current flowing across heart). I was always taught "keep one hand in your pocket" when working on high voltage systems.

Robert

[John Rumm]

Assuming the water pipes etc are equipotential bonded, then the shoes become somewhat irrelevant - the main path to earth is through the tap.

I will echo what others have said here - please don't test this stuff by touching it - especially when holding the tap. Without an RCD to save you, this really is in the "one zap and you are dead" territory!

Is this a metal switch? If not then it must have enough conductive stuff contaminating it for it to have become conductive.

As mentioned above - this shock scenario is *usually* fatal. (my guess is that you have not got a hard connection to live here, but a resistive one. Hence your ability to post without the need for a seance!)

Not necessarily - but the cause needs investigation urgently.

It sounds like is more than one fault here. The toaster test shows that the earth connection to the socket is not earthed - if it were you should not have got a shock, and more importantly a fuse should have blown. Its possible the earth is intact on the circuit - but disconnected (or high resistance) into the socket terminals. It also sounds like there is a bridge to live somewhere. This could be accumulated water etc in the socket switch itself, it could be a damaged cable either in a socket box or in a wall somewhere, or an insulation failure. It could even be a failed mains input filter on an appliance.

You need to isolate the circuit *NOW*

Then you need to set about finding the fault methodically and safely, or getting in someone who can.

If you are confident that you can DIY, then you need some test gear; at least a basic multimeter.

If you want a set of basic tests to carry out, then post back and I will list some.

There is also some guidance here:

[Andy Dingley]

In that case (plastic switch), it sounds like there's damp in the switch. You still have fault #1, but maybe not fault #2 (check though). As the impedance is high and the current low (you're shocked, not dead) then it isn't yet enough to pop the fuse. I would be expecting an RCD (if you had one) to have kicked in by now.

If you wipe the switch down with vinegar for dubious bacteriolgical reasons, you'll find that vinegar's a better conductor than codensed steam or absorbed water in accumulated grease and you wind up dead again - Restaurant kitchen in Bristol a few years back, AFAIR.

Fitting an RCD to all the sockets _except_ the kitchen really wasn't the best choice. The kitchen is where you need it!

[chrisj.doran]

Replacing the socket will be a lot cheaper than calling a professional. Please buy a cheap test meter while you're at the shop, as testing using your heart is really not a good idea, and my taxes pay for the ambulance service.

It's not unknown for plastic switches to "leak" electrically, either due to careless cleaning as others have suggested, or a bad batch of plastic which is porous, especially problematical in humid rooms like kitchens.

Chris

[Old Git]

I always worked on the principle of, stand on a rubber mat and get someone else to test it.

[Peter Crosland]

Turn off that particular circuit and get a professional inspection done without delay.

Peter Crosland

[Bill Wright]

He sounds as if he is leaping, but not to conclusions.

Bill

[NT]

I couldnt agree more. The OP should never work on mains electrics, and this is a potential fatality. That or a joke.

NT

[geoff]

Got one of those yesterday - finger to finger

woke me up a bit ...

[Dave]

About 7 years ago, I was doing some electrical work for my sister in law while she was working. One day, her daughter came round to see me and said that she was getting a jolt from a light switch and would I take a look at it. Now I am not an electrician, but I have learned much about safe practices and such things from my hobbies. So I volunteered to go round and look at it right away.

When I got to her house, I found that she had sensibly put some tape over the switch toggle. I took this off and operated the switch and it did give out a jolt. I took the switch off the wall after pulling the fuse and putting it in my pocket.

It turned out, that due to its age, it had picked up a lot of crud and you could see where the electricity had tracked through to the outside of the switch. I went out and bought another one and fitted that. End of shocking story :-)

So tracking does happen.

Dave

[newshound]

My money would be on tracking too

[Calvin Sambrook]

This is wrong, funny, scary and sad on so many levels.

On one level it's Darwinian. You obviously don't know enough or care enough to protect yourself from the most basic of dangers. According to Darwin there will always be risk-takers and natural selection will ensure that the more extreme of them have their genes de-selected from the pool. We're watching natural selection in action, the question is which side of the line are you?

On another level you have mis-understood the meaning of DIY. The purpose of DIY is to provide an excuse to buy expensive tools not to be one. There are a number of tools for testing electrical circuits but the human body is not one of them.

On yet another level it's people like you that encourage the Nanny State to impose ever tighter and sillier rules on the rest of us to prevent stupid accidents. Part P came about precisely because the government believed that by tightening the rules they could prevent or at least ameliorate the effects of stupidity. And to a large extent they were right. Clearly they don't understand the long term need to allow failure.

Please stop. Right now. Then choose which of the following (both accurate) pieces of advice to follow:

1. Don't attempt to fix it unless you understand the safety implications. Isolate the circuit before working on it. Call a professional if you are unsure.
2. The human tongue is sensitive to electricity and can be used to check for voltage. Try it first on a 9V battery then progress it higher things.

[geoffr]

Thanks John. I've read the information in the link you posted, but if you can provide a set of basic tests then that would be great.

If the tests prove negative then I assume that it's simply a tracking problem as some of the other posters have suggested. The sockets have been wiped a few times and there does appear to be a fair amount of debris around the edges of the switch.

I have isolated the circuit by removing the fuse.