Results 1 to 6 of 6

Thread: Leakage electrical current in water taps

  1. #1
    New Member
    Join Date
    May 2020
    Location
    Durban
    Posts
    2
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Leakage electrical current in water taps

    Good morning.

    I have a client who is in the process of selling his house and I did a compliance certificate for the property. All my tests and readings obtained is normal and the earth continuity throughout the property is 0.1Ω max. The bonding is also displaying 0.00Ω on my Insulation Resistance tester. All the water pipes have been properly bonded and connected to the main earth terminal. Since replacing his geyser a few months ago, he has reported to me that he feels "shocking"/"electrical tingling" sensations whenever he is in the shower and he touches the taps. My team and I have been back to his house now on a number of occasions and I cannot detect any potential difference between the water pipes (hot and cold) and earth. We have installed additional earth continuity conductors and I have even bonded the cold water and hot water pipes at the point where it enters through the wall into the bathroom and ran an earth continuity conductor from the Supply authority's earth terminal at the kWH meter box which is about 1m away to these pipes.

    He reports that everything seems to be normal for a few days and then suddenly for a day or two he experiences this issue. He contacted me yesterday and told me that he feels the shocks underneath his right foot when he touches the taps, whilst in the shower.

    When I did my tetsts, I obtained an Earth Loop Impedance reading of 0.57Ω, Voltage between Neutral and Earth at the point of supply is 0.726V and as I previously said, I get 0Ω earth continuity readings between the earth terminal in the DB as well as the meter box's supply earth terminal. The geyser is connected through earth leakage and it should trip if leakage currents do occur. I tested the earth leakage, which I replaced about 3 years ago and it works fine, tripping at 30mA. As I said, it is a brand new geyser and element (less than 6 months old). According to him this issue started after he had the geyser replaced, Before we did the certificate of compliance. He also said to me that he had the plumber back there a number of times to check the plumbing before he contacted me.

    I did notice that his water supply is polycop up to the point where it comes out of the ground against the house and then it connects into copper pipes. He told me that he has been in the house for over 20 years now and it is the first time that he experiences this problem.

    Has anyone on this forum ever come across a problem like this? As I said, we've been back to his house on a number of occasions now and cannot find anything out of the ordinary.

  2. #2
    Diamond Member Justloadit's Avatar
    Join Date
    Nov 2010
    Location
    Johannesburg
    Posts
    2,879
    Thanks
    104
    Thanked 581 Times in 495 Posts
    Blog Entries
    1
    Do a forum search with "Tingling shower" as search strings or some other key words, and you will find a number of posts referring to similar problems you are mentioning.
    Here are 2 which I experienced on one of them
    Tingling while fiddling shower taps during shower
    Electrical Charge in shower
    Victor - Knowledge is a blessing or a curse, your current circumstances make you decide!
    Solar and LED lighting solutions - www.microsolve.co.za

  3. #3
    Bronze Member
    Join Date
    Mar 2019
    Location
    East london
    Posts
    160
    Thanks
    4
    Thanked 26 Times in 25 Posts
    Quote Originally Posted by Bofie View Post
    Good morning.

    I have a client who is in the process of selling his house and I did a compliance certificate for the property. All my tests and readings obtained is normal and the earth continuity throughout the property is 0.1Ω max. The bonding is also displaying 0.00Ω on my Insulation Resistance tester. All the water pipes have been properly bonded and connected to the main earth terminal. Since replacing his geyser a few months ago, he has reported to me that he feels "shocking"/"electrical tingling" sensations whenever he is in the shower and he touches the taps. My team and I have been back to his house now on a number of occasions and I cannot detect any potential difference between the water pipes (hot and cold) and earth. We have installed additional earth continuity conductors and I have even bonded the cold water and hot water pipes at the point where it enters through the wall into the bathroom and ran an earth continuity conductor from the Supply authority's earth terminal at the kWH meter box which is about 1m away to these pipes.

    He reports that everything seems to be normal for a few days and then suddenly for a day or two he experiences this issue. He contacted me yesterday and told me that he feels the shocks underneath his right foot when he touches the taps, whilst in the shower.

    When I did my tetsts, I obtained an Earth Loop Impedance reading of 0.57Ω, Voltage between Neutral and Earth at the point of supply is 0.726V and as I previously said, I get 0Ω earth continuity readings between the earth terminal in the DB as well as the meter box's supply earth terminal. The geyser is connected through earth leakage and it should trip if leakage currents do occur. I tested the earth leakage, which I replaced about 3 years ago and it works fine, tripping at 30mA. As I said, it is a brand new geyser and element (less than 6 months old). According to him this issue started after he had the geyser replaced, Before we did the certificate of compliance. He also said to me that he had the plumber back there a number of times to check the plumbing before he contacted me.

    I did notice that his water supply is polycop up to the point where it comes out of the ground against the house and then it connects into copper pipes. He told me that he has been in the house for over 20 years now and it is the first time that he experiences this problem.

    Has anyone on this forum ever come across a problem like this? As I said, we've been back to his house on a number of occasions now and cannot find anything out of the ordinary.
    There's a bad neutral connection either in the stubby on the pavement if it's an underground supply, or a bad neutral connection in either the roof box or on the pole if it's an overhead supply. Have this problem regularly. Occurs more often at the coast due to corrosion. Has nothing to do with bad earthing. The fault is definately on the neutral.


    Cheers ... Derek

  4. #4
    Diamond Member AndyD's Avatar
    Join Date
    Jan 2010
    Location
    Cape Town
    Posts
    4,753
    Thanks
    555
    Thanked 904 Times in 731 Posts
    Quote Originally Posted by Bofie View Post
    ...The bonding is also displaying 0.00Ω on my Insulation Resistance tester.
    Testing bonding with an IR tester won't give you a meaningful reading. IR testers are designed to be accurate in the kiloohms and megaohms range and highly likely to be wildly inaccurate for sub-ohm resistance measurements.

    The earth leakage will trip if there's 30mA of leakage current but to get a tingle in the shower there's probably only around 2-5 mA involved so it won't trip. Even a 10mA shock would more likely be reported as a 'shock' rather than a 'tingle' and if it was 20mA leakage happening I can guarantee the guy wouldn't be showering any more..
    _______________________________________________
    I am special and so is Vanash.
    _______________________________________________

  5. #5
    New Member
    Join Date
    May 2020
    Location
    Durban
    Posts
    2
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Quote Originally Posted by AndyD View Post
    Testing bonding with an IR tester won't give you a meaningful reading. IR testers are designed to be accurate in the kiloohms and megaohms range and highly likely to be wildly inaccurate for sub-ohm resistance measurements.

    The earth leakage will trip if there's 30mA of leakage current but to get a tingle in the shower there's probably only around 2-5 mA involved so it won't trip. Even a 10mA shock would more likely be reported as a 'shock' rather than a 'tingle' and if it was 20mA leakage happening I can guarantee the guy wouldn't be showering any more..
    Good morning. Thank you for your reply. With reference to your reply, which instrument, in your opinion, is best suited for bonding and earth continuity testing. I have been told by an instructor in a previous SANS 10142 refresher course to use my Insulation Resistance tester set to the Ohm scale as the test instrument needs to have a no-load d.c. or a.c. supply voltage of 4V to 24V and a current of at least 0.2A. I was told in this training session that the IR tester on the Ohm scale will provide the required voltage and current, and not the continuity function ("bell tester") on the common multi-meter.

  6. #6
    Diamond Member AndyD's Avatar
    Join Date
    Jan 2010
    Location
    Cape Town
    Posts
    4,753
    Thanks
    555
    Thanked 904 Times in 731 Posts
    Low resistance tests (less than 1 ohm) are probably the most difficult type of test to get an accurate result for. As you mention you need a tester that introduces a substantial current at a relatively low voltage into the circuit and most IR testers can't do this because an IR test is pretty much the opposite ie it uses very high voltages and small currents to look for extremely high resistances. Another factor for making low resistance tests is that even the resistance of the tester leads can introduce an enormous error to the test result so I'd recommend using a tester that can 'null' the leads to take them out of the equation.

    If your instructor has indicated that your particular IR tester is suitable then I've got no reason to suggest otherwise without knowing the specifics of your tester; it's just some general observations why I wouldn't normally reach for an IR tester if I was checking bonding impedance.
    _______________________________________________
    I am special and so is Vanash.
    _______________________________________________

Similar Threads

  1. Line taps ( one size fits all )
    By Derlyn in forum Electrical Contracting Industry Forum
    Replies: 0
    Last Post: 21-Feb-20, 08:11 AM
  2. Low earth leakage tripping current
    By SeanM in forum Electrical Contracting Industry Forum
    Replies: 4
    Last Post: 15-Mar-19, 07:19 PM
  3. Tingling while fiddling shower taps during shower
    By Justloadit in forum Electrical Contracting Industry Forum
    Replies: 31
    Last Post: 08-Apr-13, 09:19 PM
  4. Electrical and Water meters audit
    By IMHO in forum Electrical Contracting Industry Forum
    Replies: 4
    Last Post: 06-Mar-13, 08:27 PM
  5. electrical over current protection
    By mikilianis in forum Electrical Contracting Industry Forum
    Replies: 8
    Last Post: 21-Jan-10, 03:30 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
  •