Tingling while fiddling shower taps during shower

[AndyD]

The thing with induced or capacitively coupled voltages is that they can be deceptive. Depending on the input resistance of your test meter you'll get different voltage readings. The whack you get from it is more down to the energy it can deliver, as previously stated this is more about the Amps or Joules.

If you can see the voltage on your tester then at least you can get a handle on what is causing the fault. What 2 points did you get your 6VAC measurement between? I would first try to narrow it down to which circuit is causing the reading, isolate all circuits at the DB, check that the 6 Volt reading has gone then reset each circuit one by one to establish which is the guilty one.

[Justloadit]

Hi Andy,

I placed a copper wire, not the best connection as it has no real point to bolt too, between the taps and the drain hole, then let the shower water run, measured between the taps, and the shower floor which are earth type of tiles, which was now damp. At this time the only circuit that I had isolated was the geyser. Will do a further test with all the other circuit breakers.

I was hoping that the wire would have eliminated the tingling feeling but it seems not to have made any difference.

[Justloadit]

OK I have now managed to get a measurement with out the shower flowing. By placing the meter between the taps, and a tile joint which was damp, I managed to measure the 6V. So it seems there is this residual voltage flowing in between the copper pipes, which in the shower come from the ceiling and chased into the wall and the ground cement.

I switched off all the CBs, and even the EL isolation switch, which disconnects both live and neutral, and there still was a reading. Off course I could not remove the earth wire, and bear in mind at the meter box, the earth is connected to the neutral.

SO confirmation that there is no electrical fault in the house, and that this must be influenced from an outside source.

Now if there was a general ESKOM power failure, it would yield an interesting result, but there have been none for a while, so I have not been able to do a measurement.

[wynn]

As an electrical ignoramus I would also check appliances such as washing machines, dish washers, ice machines and fridges with water connected for ice/cold water dispensing. one of them could be causing a crossover.

Oh and change your geyser element and thermostat.

[AndyD]

Is the meter box on your premises?

As a final test you could isolate the entire DB at the main breaker and disconnect the main incoming earth from the earth bar. Obviously don't reset the supply without reconnecting the main earth again. If the 6 volts test result disappears then it pretty much proves that your incoming earth is at an elevated voltage to actual earth.

If this is the case then by all means contact the council but my advice about adding an additional decent length rod close to the DB still stands as a good option. Additional earth bonding to the house foundation steelwork if possible would be even better.

Out of interest, did you physically check all electrical points in the vicinity of the shower for signs of damp?

[Justloadit]

Yes the meter box is on my premises.
There is only a single 80Amp breaker on the live, and not much space in the box. Not being a qualified electrician, and not having a good set of tools, I am a little apprehensive in removing the earth at the meter box, as there is really no protection there if something goes wrong. Recently our neighbours house burnt down, and burnt the over head lines, causing them to snap, and they apparently were jumping and flashing on the ground. It only stopped when ESKOM switched the transformer breaker off.

Removing any wires at the DB box requires proper tools, which I do not poses here, and doing it haphazardly is not really safe for me to do, so I will simply lay a complaint at ESKOM, and the next time I come round, I will see if I can bring some earthing spikes and do what has been suggested here.

I did do a visual around the 2 showers, but can not see any dampness outside or around the showers, besides the usual damp you get in a shower after being used. I also can not see any damp around the light fittings and switch boxes on the walls adjacent to the shower areas.

Having switched off the Live and Neutral via the EL switch, and still had the same symptom, means that the earth wire, connected to the neutral at the meter box, which is connected to the house plumbing, is the last link to make the final decision.

[AndyD]

Yes the meter box is on my premises.
There is only a single 80Amp breaker on the live, and not much space in the box. Not being a qualified electrician, and not having a good set of tools, I am a little apprehensive in removing the earth at the meter box,

I wasn't suggesting you remove anything at the meter box, I was suggesting you can knock off the supply and isolate the power to the house and only then remove the earth from the main earth bar in the DB to see if the stray voltage in the shower disappears. Don't do anything you're not comfortable with or competent to do correctly and safely. Only disconnect the earth when the power is isolated and don't restore power without the earthing being reconnected and tested first.

[Justloadit]

Ha, misunderstood you the first time round.

Thanks for all your help, it has helped considerably in this endeavour.
I will be doing the copper spike thing, as this will be in my opinion the most practical at present.

[Dave A]

Is the drainage pipe from the shower metal or plastic? If it's metal, bond it into the earth wiring.

Personally I think Andy's idea of using the steel reinforcing in the slab as an earth net is probably going to produce the best return on effort. Exposing a reinforcing rod that runs under the shower and bonding that to earth sounds like less of a mission than sinking an earth rod into solid rock.

[ians]

And a little more thumb sucking, as i mentioned without being on site.

This is what i see, a little farm house in the middle of nowhere, being fed from a pump which "could" be feeding both the houses or affecting the other house via an electrical or water connection . The electricial current/voltage must be coming from a fault somewhere, and thats what needs to be sorted out.

Heres my thoughts, has anyone checked that the seal on the pump motor is not leaking, asuming you have a water pump either from a borehole or a pump with a small baldder on top. to keep a constant pressure, why i am thinking along these lines is because it affects you when near the water, so anything linked to the water and electricity is wher ei would be looking, water pumps, level probes/balls, geyser elements, thermostats, and anything else you can think of which could be linked to the water.

As i mentioned in previous posts so long as the earthing/bonding is tight and correcting installed as per the sans regs and and the loop impedance readings are with the range. The only other problem, could be either a cable damaged somehow affecting the water pipes or a seal is damaged causing the water to get onto the motor or connections, it could even be rain getting in the motor terminal box or motor.

The problem with trying to give advice on the internet, i cant see what is actually happening on site and a small detail could make all the difference.

[Justloadit]

Gents, once again thank you for all your help and suggestions.

Whilst this is in the bush per se, every one has his own vision of the site, which like Ian says, makes it difficult to offer advice with out being on site.

The area is a nature reserve, and has been sub divided into a typical residential suburb, however there are a few municipal services provided, such as water and ESKOM. There is no refuse or sewerage, so that the current solution is a typical "French Drain", or a cavern, dug out in the ground, in which all the drain pipes are connected. The reduction of the sewage is relied on bacteria, and hence the care of not throwing chemicals into the drain pipes, ion order not to kill the bacteria. If extended use of the sewage is made, then drain needs to be pumped out.

All sewage pipes are plastic. My closest neibour does not have the problem, and after careful investigation to his property, which he built himself, I noted that all copper pipes in his plumbing system were laid out in the concrete floor, as opposed to the the other houses built in the area, in which the plumbing is done in the ceiling, and chased down the walls to the taps.

So Andy's idea of the copper rod, or the connection to a reinforcing bar in the concrete makes sound sense. Unfortunately whilst the foundations are concrete, which I observed during the construction of the house, there is no steel reinforcing in the foundation, as it was not structurally required. This poses a problem of a simple connection.

I have noted that the "drain" box was originally made with a concrete floor and brick walls, with a concrete top. If I can knock a copper rod next to the drain wall, i think i will be able to achieve the earthing.

Ian, even after switching the mains off, in which the Live and Neutral were isolate, except for the earth, which is connected to the Neutral in the meter box, I still measured the 6V, so the fault in my opinion would be with the ESKOM supply.

[Dave A]

I have noted that the "drain" box was originally made with a concrete floor and brick walls, with a concrete top. If I can knock a copper rod next to the drain wall, i think i will be able to achieve the earthing.

That really should do it. The goal is to get the local earth potential at the same level as the Eskom neutral.

[Sparks]

Hmm, been quite lively since I was last here. I take it the 6V is Neutral to Earth. That would be the Elevated voltage. The EV reading is usually taken at the DB when I do my inspections so that if it is too high I can either have the monkeypality see to it or if need be switch off the supply. Elevated voltage is not a fault condition and will not cause the tingling. On getting a 6V Elevated Voltage reading, I would carry on with my inspection without batting an eyelid, that is average in some areas of Port Elizabeth.
In light of the further information you have provided I now suspect a floating earth. What are your earth continuity readings? The higher your CB the lower your earth continuity needs to be in order to be compliant. As previously also mentioned, I think it was by Andy, your bonding conductor resistance is also important. Are your bonding conductors copper? What gauge is your earth wire from the DB? Are the earthstraps secured onto clean areas? Having a floating earth on your plumbing could cause the tingling too. You did say that you are on a rocky outcrop. I take it you then have an overhead supply. Have you checked the insulation of the cables where they enter the roof?

[Justloadit]

Hi Sparks,
The 6V reading is not between Neutral and Earth at the DB box, but rather between the copper water pipes in the wall, and a damp section on the floor tile grout.
This is not a conventional type of fault in the house wiring. The meter box, which is on a pole some 6 meters from the house, is fed via an overhead three phase, twisted insulated line, and the Neutral is an open silver conductor, which also acts as the mechanical carrying component of the line to the next pole. At the pole there are 2 meter boxes, back to back, which have a single phase KWH meter in each box. The meter box which feeds the adjacent properties, the Neutral and earth have been physically joined. Then there is a 4mm diameter exposed copper cable which goes down the side of the pole into the ground. Coming up from the same position in the ground, there is a copper wire going to the earth connector of my meter box which feeds my house. Effectively there is no physical connection in my box, between Neutral and the earth, as with the adjacent meter box, however the electrical connection of earth and Neutral is done in the join in the ground, which I assume that ESKOM placed a earthing spike.

When I measure between the earth and the Neutral, I get no voltage. After some time and experimentation, I was able to get a reading in the shower, with out the water flowing, which made the measurement exercise much simpler, I was able to get a 6V reading between the copper pipes that have been chased in the wall, and fed from the ceiling and a wet spot of grout between the shower floor tiles. I switched off the main power to the house through my DB box, which has a earth leakage isolator, not circuit breaker, there is a 60 amp circuit breaker before the EL switch, which then feeds the other CBs in the DB box. So effectively there was no Live or Earth in the circuit after the EL switch, and I still measure the 6V, which meant that the leaking voltage was not coming through the house circuit. It must be noted that at this point, the earth and Neutral connection was still in place at the neibours meter box.

Andy suggested, that I remove the earth in the DB box during this part of the test. Since I was on holiday, I did not have any decent tools with me to perform this part of the test, and decided that I had already de3lved more deeply into this than my qualifications would allow, and decided that I will contact ESKOM next week and lay a complaint to see if they could rectify the problem.

Other neighbours further up and further down from me, fed from the same ESKOM overhead line, do experience this tingling feeling when they shower. Their solution was to get plastic tap covers. My adjacent neibour, not fed from the same pole, but fed from an arrangement as the pole outside my house, does not get this tingling feeling. at first I thought that since he does not use a electrical geyser, he would not get the problem, but after some investigation I noted that all his plumbing planned at the onset of the construction of his house, comes through the concrete floor, which fits into Andy's recommendation of the earth strap into the concrete.

I hope that I have been able to describe the actual setup.

[Sparks]

Yip, your loop impedance test or earth-resistance test would have shown it. Eskom will need to come give a decent earth spike at the pole. Your waterpipes are earthed by way of Eskoms earth wire. This is a "protected earth/neutral conductor.(the same one) They must split before your installation and the 1 terminated to the ground. Being rocky they must have decided to call it a day before getting a good reading or else it might have been done while the ground was moist. Your earth from Eskom is also Neutral and from there to the actual moist ground(true earth) you are getting 6V elevated voltage. When Eskom have earthed their side properly you will probably still have the elevated voltage, maybe a bit lower but, without the tingling. Please keep us posted as to the results of Eskoms' tests and the outcome.