earth leakage

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Hi all,

Last weekend we have had an electric shock from the sink, at the time the washing machine was going, the washing machine is right next to the sink. We first called out the a washing machine engineer to have a look as for the past year we have had water coming out of the soap dispenser, so i thought water must have got into the electrics and was going to earth. The engineer said that we must call in an electrician, as the tested all the downstairs sockets and they all showed a earth leakage, upstairs was all OK. An electrican came last Friday and said that the problem was a loose earth wire going into the consumer unit, after tighting the wire in the unit, he tested the earth and found it to be OK, he did say that the residual voltage was high and the earth sparked when it was being fixed. Today my daughter got a small electric shock when she put her hand in the pond which has a small pump going, the washing machine is now also pluged back in. So we are pretty worried as to why this is happening. Plus why aren't the trip swiches going in the CU??

We have called the electrician again to come back to have a look, but he was worried also after he left and has sent up a letter saying that he was worried as to why there was an electric spark when he tightened the earth up at the unit, stating that a electric current must be flowing.

He also states that there must be a latent earth fault in the circuit somewhere.

He has suggested replacing the CU and if that did not solve it a complete rewire, which could cost 1000's.

Any ideas on what could be causing it and any solutions would be a help?
 
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One get another electrician changing the consumer unit will not remove the fault although likely it will trip rather than giving you a shock.

Tracing earth faults can be a problem but only because it causes a RCD to trip not because it gives some one a shock.

He should have used an earth loop impedance tester to measure the Zs at the socket but these meters are not cheap and my first thought is he did not have one?
 
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Best to get a different electrician in. It most likely is an earth leakage issue but blindly changing the consumer unit is not the first thing to do (though it may need to be done for reasons of fitting RCDs)

The first thing to do is a PIR periodic inspection to see where the installation stands in regard to current regulations. Paying close attention to main protective bonding and performing quite simple diagnostics to determine if there is a significant earth leakage or earth fault.

Assuming you have no RCDs on the kitchen circuit? Do you know what type og earthing arrangement you have? Earth rod?
 
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One get another electrician

You mean get an electrician. So far they have not had an electrician.

An electrician who got a spark when connecting an earth wire to the earth bar in the CU would know there was a fault. A real electrican would make sure it was safe before leaving.

scouse1965 said:
He has suggested replacing the CU and if that did not solve it a complete rewire,
Which is ludicrous. Changing the CU cannot fix the fault which is somewhere in the wiring of the house.
 
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Hi all,

Plus why aren't the trip swiches going in the CU??


Are the trip switches you refer to MCBs? Do you have one or more RCDs (residual current device) in or near your consumer unit? RCDs have a test button on them.

An MCB will probably not trip in an earth leakage situation since the fault current will almost certainly be much lower than the trip threshold on the MCB which is likely to be 32 amps for a kitch ring circuit. It sounds to me that you do not have an RCD on the kitchen circuit.

You need a properly registered, technically competent electrician.
 
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The house was built in the 1970's there are no RCD's, all I have done is change the old wired fuses for circuit breakers. Don't know if it has an earth spike. :cry:
 
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The house was built in the 1970's there are no RCD's, all I have done is change the old wired fuses for circuit breakers. Don't know if it has an earth spike. :cry:


Thanks for the reply. Yes, you do need a good competent registered electrician and urgently.

Two things

1) have them find the fault and quote to rectify.
2) have them do a periodic inspection report (PIR)

Do not have the first person back for obvious reasons. Check out
www.competentperson.co.uk

There are really two problems:

1) Something in the house is "leaking" current to the earth circuit. Could be something plugged in or something fixed like an immersion heater or even damp wiring.

2) In a fully compliant installation the leakage would either be dissipated safely and/or automatic disconnection would occur.

Automatic disconnection won't occur in your installation because you do not have an RCD.

Ultimately you may well need a new consumer unit and remedial work on your earthing arrangement/protective conductors but have the PIR done first and that will reveal all provided it is done by a professional.
 
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In theory a house built in the 1970's should have either a TN earth or an earth leakage device if it's a TT system (uses an earth rod). But at that time there was no registration of electricians and one can never be sure it was installed correctly.

In the time between the house being built and now there has been a move to replace water and gas pipes in the street with plastic and where the correct methods were not used houses can end up with no real earth system able to automatic disconnect in the event of a fault.

As already said you will likely have at least two faults. You need an electrician to sort it out but using a plug in RCD like this one which is 10ma may help protect things like your pond in the mean time.
I have selected a 10ma version as if you then have 30ma RCD fitted to house these will still provide so discrimination for things like your pond.

As already said the guy you found should not be classed as an electrician. People who do work like that do find themselves the wrong side of the law. Unfortunately it does happen I we still find people who are more intent on knocking off on time than leaving the premises safe.
 
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As already said, get a second opinion from a different sparkie.

I was getting shocks off brass switch plates and my electrician laughed at me saying it wasn't possible, as everything is earthed. Told me not to go round the house in bare feet.

Patronizing sod even showed me the earth wire.

I investigated myself and found that those earth wires didn't actually go to earth.

Could have been lethal, measured 253v at switchplate to rad.

So yes, get someone who knows what they are doing!!!
 
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Firstly I want to say a big thankyou to everybody who has posted a reply to my problem. You have all been a great help.

I asked my wife who was with the electrician if he tested the z's, she said that he did. Can I check for appliance leakage by disconnecting all appliances? I have tested the downstairs circuit using a trip switch, it cuts out all the time.
 
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Firstly I want to say a big thankyou to everybody who has posted a reply to my problem. You have all been a great help.

I asked my wife who was with the electrician if he tested the z's, she said that he did. Can I check for appliance leakage by disconnecting all appliances? I have tested the downstairs circuit using a trip switch, it cuts out all the time.


It is possible to get perfect Zs readings with no earth connection. For example if the main earth terminal at the consumer unit is connected to the neutral block. Zs readings in isolation don't mean very much.
You can go around unplugging things but it may be the immersion heater or the house wiring. If its the house wiring then it may be a small section leaking a lot of current or the sum of small leakages over much of the wiring. Even if you found the main source of leakage you still have general earthing problem.

This is job for a professional and it is urgent. Someone could receive a fatal electric shock.
 

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