Page 1 of 4 123 ... LastLast
Results 1 to 10 of 32

Thread: Tingling while fiddling shower taps during shower

  1. #1
    Diamond Member Justloadit's Avatar
    Join Date
    Nov 2010
    Location
    Johannesburg
    Posts
    2,671
    Thanks
    88
    Thanked 544 Times in 460 Posts
    Blog Entries
    1

    Tingling while fiddling shower taps during shower

    I have a little holiday house in Limpopo province, and ever since it was built, some 7 years now, when ever we have a shower, most times, while showering, we get a tingling feeling when we adjust the taps to get the temperature right. When there is no water we do not feel the tingling feeling in our hands, only once the water runs. At first I thought that there may be a faulty element, and I have switched the geyser circuit breaker off, but still get the sensation when adjusting the taps. Now it is not a jolt or anything like that, but have the feeling or presence that there is some small electrical current flowing.

    The whole plumbing system is made of copper pipe, and I have checked, that the copper pipe at the geyser is earthed. I have not been able to check that the earth of the geyser is earthed at the DB box, my meter leads are not long enough to go from the roof to the DB box .

    I have checked with an ohm meter, and there is continuity between the taps and shower head, between the shower taps and basin taps. I have tried measuring the voltage between the taps and shower when water is flowing, between the taps and the water on the floor when the shower is pouring water, and was not able to measure AC or DC voltage at all. I have noted that at the meter box on the pole, that the earth is connected to the Neutral.

    Can some one shed some light for the reason that this may be happening, and what I can check. There is an earth leakage in the board, and if I press the test button, it does trip.

    I am a little concern every time my family or I have a shower, that it may get progressively worse, but to date it has not.

    What can I check, do or whatever to stop tingling from happening.
    Victor - Knowledge is a blessing or a curse, your current circumstances make you decide!
    Solar and LED lighting solutions - www.microsolve.co.za

  2. #2
    Platinum Member
    Join Date
    Apr 2010
    Location
    KZN
    Posts
    1,587
    Thanks
    76
    Thanked 138 Times in 118 Posts
    Simple, make sure the pipes are bonded hot to cold close to the geyser and the bonding is earthed to the geyser, then make sure the geyser is earthed back to the DB. Then do a loop impedance test, In fact i would do a loop impedance test at the geyser just to be sure.

    I would plug in my earth leakeage plug tester, verify that all 3 lights are on then test the e/l unit by turning the knob until it trips, which should be around 20 - 25 mA, if it doesnt trip you know either your earth leakage unit is fault or you have a bigger problem inadquate earth, which you might pick up doing the loop impedance test.

    It could just be a bad earth connection, all speculation without being on site to see the big picture.

  3. #3
    Diamond Member AndyD's Avatar
    Join Date
    Jan 2010
    Location
    Cape Town
    Posts
    4,403
    Thanks
    513
    Thanked 854 Times in 687 Posts
    Quote Originally Posted by Justloadit View Post
    I have noted that at the meter box on the pole, that the earth is connected to the Neutral.
    This sounds like a TNCS earthing arrangement. There could also be an earth rod on your property usually at the first point of entry. The E-N connection on the council side is normal.

    To receive an electric shock there is usually two completely separate problems occurring simultaneously.

    Firstly there's usually an insulation fault (low IR). Insulation is what prevents current 'leaking' to earth in a healthy or compliant circuit. As the value or effectiveness of the insulation decreases the leakage current to earth increases.

    The key word here is earth (ground for our US members). The current takes the path of least resistance so if the earth is good (low resistance) then the fault current flows freely away down this path instead of flowing through someone who touches the appliance with the insulation problem.

    This leads to the second problem required when you get a shock or tingling in your case. If the earth wiring (cpc) is high resistance then any fault current present on a circuit or appliance will happily look for an alternative route of lower resistance to flow to earth. In most cases this is the poor soul who comes into contact with it.

    Okay, I've tortured you with enough technical rubbish so I'll suggest a few things you might do to fix it.
    You say you still get tingling with the HWC circuit isolated, this kinda throws a spanner in most of the usual suspects.

    1. I'd certainly double check any earth bonding around the cylinder, remake the bonding connections and clean the copper under all the straps so it's shiny.
    2. Visually check all the connection points at the cylinder, the isolator switch and in the DB. Test the earth impedance of the cylinder earth and preferrably use a tester such as a loop impedance tester that can put a high current pulse (40Amps) through the earthing.
    3. Megger test the cylinder element at 1000v to check its insulation integrity, it should be at least 10Mohms.



    All these tests so far are basic bread and butter and from what you say I doubt you'll find the problem there but rather start with the easy obvious stuff and rule it all out of the equation before you go complicated. Once you know the cylinder and its associated circuit are fine it's time to get into the DB. Visual first, check all earth and power connections for tightness, corrosion or overheating damage. Determine if you have an earth rod on the property which would indicate you have a PME system. If you do then impedance test the rod on its own and disconnected (Ra test), also visually inspect the wiring connections to the rod. Same goes for any bonding from the DB to plumbing, check the integrity of the cabling, straps and connections.

    If everything checks out then it starts getting complicated I'm afraid. I'll try explain but I can't advise on how to proceed with localizing without seeing the shower and the surrounding areas. There's actually 2 directions you can get a shock. The usual direction is where you have your feet on a zero volt ground and you put your hand or fingers something that has a fault and a high touch voltage. The fault current then runs from the faulty item and through your body to ground or earth.

    Click image for larger version. 

Name:	Shock.jpg 
Views:	1671 
Size:	24.9 KB 
ID:	3118

    The other way you can get a shock is if you're standing on a floor that is at a voltage above zero and you touch a good earth. This is always a possibility with a shower becase they often leak moisture into the surrounding area and the taps are nearly always a good earth point.

    I've seen several similar scenarios that are a bugger to locate and usually end up with tiles removed, jackhammering and waterproofing being required. You need to think out of the box as well as in three dimensions. The trick is to find all the electrical cabling and points in the vicinity of the shower and insulation test those circuits. I've seen damp problems in sockets in adjacent bedrooms giving shocks to users of the shower in the next room. I've also seen a stove isolater that was getting damp because of a bathroom leak directly above giving shocks to people at the wash basin. I've also found one problem years ago where tree roots had grown through a drain pipe and a nearby garden light circuit connection was causing tingling at a kitchen sink through the drain water.

    These kinds of faults aren't easy to find even with state of the art test equipment and the patience of Job. I wish you luck and hopefully it's something obvious. I would also advise caution if you're not electrically competent, it's easy to get a fatal shock when working on equipment, circuits and in DB's, especially when there's an underlying fault that might have unexpected results. Even earth wiring can become 220V live when it's disconnected!!! You need to know how to prove isolation as well as having the necessary testing equipment. If you're not competent or unsure of anything please seek professional assistance. You've been warned.
    Last edited by AndyD; 23-Dec-12 at 12:40 AM.
    _______________________________________________
    I am special and so is Vanash.
    _______________________________________________

  4. #4
    Diamond Member Justloadit's Avatar
    Join Date
    Nov 2010
    Location
    Johannesburg
    Posts
    2,671
    Thanks
    88
    Thanked 544 Times in 460 Posts
    Blog Entries
    1
    Hi Andy,

    Thank you for your comprehensive reply. The tingling feeling is not always present, but when it does occur, it is only when the water flows. I do have a 1000v insulation tester, which I will bring with me at my next visit, and do a comprehensive insulation test.

    I am no electrician, but am familiar with electrical circuits, being an electronics designer and involved in power electronics, like speed drives switch mode power supplies and other industrial controls.

    I have done the usual of checking the connections as per your list. I suspect it is a TNCS earthing system with an earth rod. This was a new house in the bush, and from day one it always had this problem. It does have a french drain. I have checked the electrical earth connection between the water pipes and the DB board, and it does show continuity with a ohm meter. I currently do not own an impedance tester, and will seek to beg, borrow, steel or buy one, next time I come up to the house and do an impedance test.

    I did inspect the meter box, which is shared by the stand next to mine, and noted an earth wire from my box and the adjacent box going into the ground next to the concrete pole, I suspect this has the earth rod you mentioned. The meter boxes are fed from overhead lines fed from an overhead transformer, which supplies a number of houses in the area. The adjacent box has the neutral connection to the earth wire going into the ground. My box does not have this connection earth connection, so effectively the earth, neutral connection in my house is done by the neighbors meter box. These connections have been done by ESKOM and not the local electrician.
    Victor - Knowledge is a blessing or a curse, your current circumstances make you decide!
    Solar and LED lighting solutions - www.microsolve.co.za

  5. #5
    Diamond Member Justloadit's Avatar
    Join Date
    Nov 2010
    Location
    Johannesburg
    Posts
    2,671
    Thanks
    88
    Thanked 544 Times in 460 Posts
    Blog Entries
    1
    OK, I have spoken to the neibours, it seems they are also experiencing this problem, and each one of us thought it was to do with the house wiring, and this is the first time any of us has actually discussed this problem.

    I now suspect that there is either a faulty transformer, or the neutral to earth connection on the transformer secondary side may be open circuit, and hence the symptoms we are experiencing.

    I will be contacting ESKOM, and hopefully they can resolve the problem. I will keep you posted, but it may take a long while, as I only pop up to the holiday house a couple of times a year.
    Victor - Knowledge is a blessing or a curse, your current circumstances make you decide!
    Solar and LED lighting solutions - www.microsolve.co.za

  6. #6
    Diamond Member Justloadit's Avatar
    Join Date
    Nov 2010
    Location
    Johannesburg
    Posts
    2,671
    Thanks
    88
    Thanked 544 Times in 460 Posts
    Blog Entries
    1
    Ignorance is bliss!.

    Now that I know where the problem is originating from,
    HOW dangerous is this situation?

    I have noted that at times the tingling feeling is more intense, and have come to the conclusion that it depends on what loads are running on the ESKOM supply line at the time, the more loaded the more intense the tingling.
    Victor - Knowledge is a blessing or a curse, your current circumstances make you decide!
    Solar and LED lighting solutions - www.microsolve.co.za

  7. #7
    Platinum Member
    Join Date
    Apr 2010
    Location
    KZN
    Posts
    1,587
    Thanks
    76
    Thanked 138 Times in 118 Posts
    thats what kills you, the current in the circuit not the voltage.

    50 000 volts on an electric fence will not kill you, but 1 amp in a 230 volt circuit will.

  8. #8
    Diamond Member AndyD's Avatar
    Join Date
    Jan 2010
    Location
    Cape Town
    Posts
    4,403
    Thanks
    513
    Thanked 854 Times in 687 Posts
    Is your RCD working (earth leakage breaker)? Does the RCD supply the whole house or just plug points? If the RCD is working correctly and it's supplying the whole house it should intervene if the leakage current reaches a dangerous level. Maybe just ramp test it in both half cycle directions just for peace of mind because all your eggs are in that basket if your earth is high impedance.

    Good luck getting the supply authority to come out this time of year I would be tempted to whack an earth rod in close to your DB and connect it to your main DB earth bar with a 10mm wire. It's not such a daunting task, if you have access to a jack hammer for a day you can use a suitable attachment to do the hammering the easy way. I would start with 2 or 3 x 2.3meter rods coupled on top of each other, anything less will lack impedance stability. If your neighbours are fed from the same Tx it would help enormously if you could persuade them to do the same. The rods, couplings, clamp connector and wiring should come to way under R1K. I might suggest you dig by hand for the first 600mm at least to avoid hitting and services.
    _______________________________________________
    I am special and so is Vanash.
    _______________________________________________

  9. #9
    Platinum Member
    Join Date
    Apr 2010
    Location
    KZN
    Posts
    1,587
    Thanks
    76
    Thanked 138 Times in 118 Posts
    what is the neutral to earth voltage at the DB or meter box?

    If it is higher than 50 volts i would switch the power off, it is a dangerous installation.

  10. #10
    Diamond Member Justloadit's Avatar
    Join Date
    Nov 2010
    Location
    Johannesburg
    Posts
    2,671
    Thanks
    88
    Thanked 544 Times in 460 Posts
    Blog Entries
    1
    There is no voltage between neutral and earth at the DB box and meter box, and the incoming supply cable is about 6 or 8 meters from the pole meter box, where there is this earth rod connected with approximate 2.5mm stranded copper wire. There is one earth leakage isolator on the incoming side, and all circuits in the house go through it. The ELB is rated at 30mA, when I push the test button it trips. I do not have any equipment which can test the 30mA, however if I connect my cell phone charger between live after the ELB and the neutral before the ELB, it trips the ELB, so it seems that it is able to pick up a low fault current.

    This place is in the bush, so there is really no municipal services other than water which is fed by a pipeline running along the stand border line, and ESKOM electricity.
    The nearest electrical wholesaler is some 55 Kms away, so it is no walk in the park to buy anything, and with all the public holidays, it just makes it almost impossible. I am also trekking back to civilization on Friday morning.
    The ground here is practically rock, so not going to be an easy task knocking a rod into the ground just any where, but I feel that I must do something to set my mind at ease.

    This is why I find it so strange, that the impedance from a human body is lower than the impedance of the copper pipe in the walls, common sense would say that there would be no current flow with a high impedance in a parallel circuit where the resistance of copper is almost zero ohms, and a human body is somewhere in the region of 200K ohms. I have even gone into the shower with my multimeter, and tried to measure the voltage in the same plane as my body, water and hands, and the darn meter does not show any voltage, AC or DC but yet I can feel there is something there. It could be the transformer has a primary leak to earth, which is causing this sensation.

    I am thinking of connecting a piece of stripped wire, along the wall in the shower from the taps, down to the shower floor, so that there is a shorter path for the current to flow, rather than using the human body, will think about how to do this in the morning.
    Victor - Knowledge is a blessing or a curse, your current circumstances make you decide!
    Solar and LED lighting solutions - www.microsolve.co.za

Page 1 of 4 123 ... LastLast

Similar Threads

  1. Stop HIV - don't shower
    By Nickolai Naydenov in forum General Business Forum
    Replies: 10
    Last Post: 21-May-12, 09:19 AM
  2. Fiddling the books?
    By Dave A in forum Business Finance Forum
    Replies: 1
    Last Post: 08-Nov-09, 03:23 AM

Did you like this article? Share it with your favourite social network.

Did you like this article? Share it with your favourite social network.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •