Tingley taps

[jimmyjazz]

I have a customer who get's minor 'tingles' from her taps. I have tested installation & found between 10 & 14 mA on main earth with main switch & breakers off. I have read threads regarding possible cause being EMFs, but can anyone help with how to remove 'tingles'? Property has correct size bonding & sup. bonding installed.

 

[m25maintenance]

ze test??????? also mite be a fault comming into the house from outside

 

[m25maintenance]

also could be faulty washing machine or some other machine causing the leakage, is the any rcd, is it tripping

 

[pushrod]

What type of consumer unit (rcd protected?) and what earthing system does it have? Did Insulation resistance tests show as ok?

 

[wacko]

Hi jimmy jazz,

I'm probably having a blonde moment but I don't understand your test.

And are the taps in the bathroom or kitchen?

Regards

 

[pushrod]

also could be faulty washing machine or some other machine causing the leakage, is the any rcd, is it tripping

If the main breaker is off nothing is running .

 

[pushrod]

Hi jimmy jazz,

I'm probably having a blonde moment but I don't understand your test.

And are the taps in the bathroom or kitchen?

Regards

probs putting an earth leakage clamp meter around main earth

 

[nickblake]

Check the earth bond to the water first also check the immersion heater ,I had a call for exactly the same thing a few months ago ,got to the house found a woman in her dressing gown shaking like a leaf , she was having a bath put her hand on the tap placed her foot in the bath and got blown across the bathroom ,infact when i tested i found every single metal item even the flush handle on the loo was live 230 volts , what had happend a fault had developed in the airing cupboard live Earth short ,the fault had blown the earth from its connection and the live had welded itself to the hot water cylinder , earth to water was not connected just coiled up under the sink one lucky woman also as has been said check the main supply you may well have a neutral fault that is back feeding down the earth ,especially on a TNCS / PME system

 

[pushrod]

Hmmm - thinking about this, if she is getting tingles their must be a voltage of 20 to 50 ish volts involved to push a current thru her. The voltage to drive the 14 mA thru the earth would be tiny (much, much smaller than one volt) bearing in mind the resistance of the earth. It could be that the current in the earth is a separate fault/problem?

Have you put a voltmeter across a tap to earth / neutral?

Be very interested to hear if you get it sorted.

 

[wacko]

Hi chaps,

I'm thinking broken sup. bond somewhere. So I'd be testing at the taps, not at the main earth.

If the touch voltage is less than 55 you could always tell the customer it's within the regs...

Eh?

 

[jimmyjazz]

Thanks for replies...Property is TN-S, Ze 0.29, PFC 0.80. 16mm Earth & 10mm bonds. Supp. bonding across pipework in boiler cupboard.Split load board, All MCB's & main switch off - reading at Main earth with leakage devise 14mA. No tingle. Circuits on tingle at taps. I think the fault is external, could it be from an adjacent property? I've got a re-visit Wednesday

 

[pushrod]

Thanks for replies...Property is TN-S, Ze 0.29, PFC 0.80. 16mm Earth & 10mm bonds. Supp. bonding across pipework in boiler cupboard.Split load board, All MCB's & main switch off - reading at Main earth with leakage devise 14mA. No tingle. Circuits on tingle at taps. I think the fault is external, could it be from an adjacent property? I've got a re-visit Wednesday

Try breakers one at a time to identify which circuit introduces the voltage at the tap. Thoroughly investigate that circuit ...

still thinking the main earth current might be unrelated, maybe a tiny induced voltage, after all that is there when the circuits are off.

Is the 14 mA still there when the circuits are on?

 

[Knobhead]

This reminds me of a fault I had many years ago in my own house. I’d just installed gas central heating, the very last job for me to do was connect the gas pipe to the gas meter. Touched the two ends of the pipe and got a spark! Not good thought I, well to hell with it jammed the pipe together and soldered the joint. On putting a clamp meter round the pipe found 25A flowing through it Turned off supply to my house, still 25A, I’m getting confused at this point I’m confused, the wife is frantic, no gas or electric now! Phoned electricity board, and after speaking to one of their engineers was told to keep both supplies turned off, they’ll get back to me. Not 2 mins later phone rings, we’ll be there in 20 mins! 4 vans and 2 overhead line wagons showed up! I did live in a rural area so supplies to the road were overhead. Much head scratching followed, at one point we disconnected the gas meter and slung that out in the back yard. In all seriousness this was the point the gas meter reader showed up It was decided to disconnect the entire road from the supply. By this time I’m not the flavour of the month with the entire road, we’ve now got 12 houses with out supply. The OH crew found a burnt line tap on the neutral. Further tests showed a neutral earth fault some where in one of the 12 houses. As I knew all the neighbours I got delegated to got to each house and isolate the supplies, how come this ended up as my job? Eventually there’s a shout from the OH crew as I isolated the furthest house on the road, “faults gone”. Electricity board senior engineer then goes in to “Hitler” mode, tells my neighbour “unsafe installation your supply will be disconnected until rectified”. While the OH crew are repairing the connections to the road I hijacked the apprentice that had come with the board and checked through the house. The apprentice found the neutral fault in a socket, the facia screw had bitten in to the core. OK now neighbours supply can be reconnected as well.

Now think about it the neutral for 12 houses was going through one 3.5mm screw. The house was bonded to the water pipe only. The current travelled along the water pipe until it got to my house, I’d just rewired and fitted CH. So it was a case of if it doesn’t move bond it, the current then went through my house and out through the gas pipe and spike. (I’ve never understood why a steel gas pipe is a better earth than lead water pipe, but it always is)? Just how in the name of god my neighbours house didn’t burn down I’ll never know. The fault must have been there for years.

Part of the reason for the electricity boards panic was there was a government fuel storage dump about 100m from the road. They use cathodic earth bonding which can cause fun and games. But had the fault been from there it would have been DC and not shown on my meter.

 

[High Tower]

Thanks for that Tony I love stories like that I'll helps someone like me with less experience figure things out in the future

 

[jimmyjazz]

Thanks Tony, I have an itch about this that points to something similar. House is down unmade road with a small group of others, I may check one of thiers too. My nearest story to yours was when I went to the usual 'I've changed the light' bang faullt. Re-wireable 5A fuse blown. Rectified fault, put fuse back in, no power to house? back to board in garage & power on, back to house power off....this took a while. Upshot was SEB dug up road & chaps drive to find perished joint. I just happened to be there at the time. Customer still looking at me sideways until the power was re-instated!