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Thread: Neutral/earth bridging method.

  1. #11
    Platinum Member Derlyn's Avatar
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    Personally, I feel that too much emphesis is placed on the fact that a relay can fail. So do earth leakage relays. I replace on average 2 each week.

    If one uses a good quality relay, then I don't see a problem. One should expect the component to do the job for which it was designed for a considerable period of time before malfunctioning.

    If you don't trust the relay, then either install 2 in parrallell or a better quality one, but then be sure to also install 2 earth leakage relays in series just in case one of them goes faulty.

  2. #12
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    I dont agree with you, using an earth leakage which should be tested frequently, is a bad example, it clearly states on the ELU device that it must be tested. The fact that people dont test them is not your fault, actually it is because you should point it out to your customer, some might say but we dont all work in domestic installations, well then you should, you should have a maintenance schedule in place that includes testing all the ELU devices in the building or site, before the DOL do their routine inspections, so there is really no comparison.

    There is nothing stopping you from supplying your customer with a plug tester, especially if they have small children and pointing out the importance of the safety shutter in the socket outlets.

    Customers understand the ELU, it is easy to access and clearly labeled in the DB.

    Not only are the neutral/earth relays being used not compliant (ender rated, some fool had a 10 amp finder relay installed for an 8 kw inverter), with no status identification or means to test if it actually functions, I dont see how you can expect the customer to monitor such a critical part of an installation (not saying an ELU is not critical)

    To add fuel to the problem, there is no way to lock out the switch tab in the app, if someone switches it off by mistake , which makes it even more dangerous. The customer has idea how the neutral/earth bonds works, where it is located or how to test it, or its application, so I would say your argument is weak.



    Quote Originally Posted by Derlyn View Post
    Personally, I feel that too much emphesis is placed on the fact that a relay can fail. So do earth leakage relays. I replace on average 2 each week.

    If one uses a good quality relay, then I don't see a problem. One should expect the component to do the job for which it was designed for a considerable period of time before malfunctioning.

    If you don't trust the relay, then either install 2 in parrallell or a better quality one, but then be sure to also install 2 earth leakage relays in series just in case one of them goes faulty.
    Comments are my opinion, unless regulations are attached to support the comment. This is social media, not a court room.

  3. #13
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    This just highlights why this discussion is so important and why the DOL should have stepped up a long time ago and cleared up this problem. I believe the only reason they are now supplied with the relay built in, because they have got away with it for this long and fortunately there hasnt been a death, so no court case, yet.

    The sad part is that the customer trusts the DOL to appoint people who are going to look after their best interest and safety for their families, yet the very people who they appointed have been going around actually threatening court action (me being one of those people), billing customers and enforcing a non compliant method , the question I keep asking and nobody wants to answer, who is going to refund the customers for the fees and costs incurred by the very people appointed.

    This could also explain why there has been no formal notification sent out, somebody is going to have to pay to fix all these non complaint installations. Fortunately customer are so use to holding their ankles why everyone has a turn.

    I have noticed many comments from customer who got installations done in 2023, compared to 2024 as the prices continue to drop. I get revised price literally every 2 weeks. An inverter purchased 3 weeks ago is R2000 cheaper today and more than R10 000 cheaper than 2023. I am surprised that there hasnt been an investigation into pricing structures for 2023.

    I recall being told that it was the exchange rate that controlled the price increases, well anyone noticed a massive reduction in the exchange rate recently?

    I would also have a bitter taste in my mouth if I paid around R100 000 more for an installation a year ago.





    Quote Originally Posted by Andrew_van_Zyl View Post
    I always installed a contactor and selected "Signal islanding mode" before. Installed a 8kW Sunsynk this week and was surprised to find PE/N bond taken care of internally.
    Comments are my opinion, unless regulations are attached to support the comment. This is social media, not a court room.

  4. #14
    Platinum Member Derlyn's Avatar
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    Quote Originally Posted by Isetech View Post
    I dont agree with you, using an earth leakage which should be tested frequently, is a bad example, it clearly states on the ELU device that it must be tested. The fact that people dont test them is not your fault, actually it is because you should point it out to your customer, some might say but we dont all work in domestic installations, well then you should, you should have a maintenance schedule in place that includes testing all the ELU devices in the building or site, before the DOL do their routine inspections, so there is really no comparison.

    There is nothing stopping you from supplying your customer with a plug tester, especially if they have small children and pointing out the importance of the safety shutter in the socket outlets.

    Customers understand the ELU, it is easy to access and clearly labeled in the DB.

    Not only are the neutral/earth relays being used not compliant (ender rated, some fool had a 10 amp finder relay installed for an 8 kw inverter), with no status identification or means to test if it actually functions, I dont see how you can expect the customer to monitor such a critical part of an installation (not saying an ELU is not critical)

    To add fuel to the problem, there is no way to lock out the switch tab in the app, if someone switches it off by mistake , which makes it even more dangerous. The customer has idea how the neutral/earth bonds works, where it is located or how to test it, or its application, so I would say your argument is weak.
    This is one issue where I disagree with you.

    Questions to ask.

    1. On inverters that have an output intended for an external relay to be fitted for neutral earth bridging, does that inverter know if that output
    has been used or not ?
    Without knowing the answer, I will hazard a guess and say, no.

    2. If that dedicated output is used for a relay and the relay somehow fails, would the inverter know that the relay has failed ? Once again, without
    knowing the answer, I would hazard a guess and say, no.

    3. On inverters that have an internal relay built in for this purpose, would the inverter know if the relay has failed ? Without knowing the internal
    configuration of the inverter control system, I would once again hazard a guess and say, no. ( Will have to research this further to ascertain a
    definitive answer )

    4. On inverters that neither have an internal relay or a dedicated output for an external relay, have you as the installer, taken reasonable
    action
    as to ensure that the installation is reasonably safe as declared on the COC ? If you fitted a good quality relay, rated to carry
    the output current of the said inverter, for the purpose of bridging the neutral and earth when in islanding mode, then my answer would be,
    yes.

    I bounced this off an attorney and his opinion is that as long as you, as the installer, can prove that reasonable action was taken to prevent any injury or death, then it's going to be extremely difficult to prove any guilt. I think we all too often forget about that word " reasonable ".

  5. #15
    Diamond Member Justloadit's Avatar
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    There is a simple way of knowing when there is no Neutral/Earth bond, in other words detecting lack of the bond.

    I am wondering if there is any way that I can commercialize the solution, getting tired of others making money off my ideas over the years, and even get them phoning me to get my thoughts on how to solve their problems, and never even getting anything for it, but they get paid handsomely for "solving the problem"
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  6. #16
    Site Caretaker Dave A's Avatar
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    Quote Originally Posted by Justloadit View Post
    There is a simple way of knowing when there is no Neutral/Earth bond, in other words detecting lack of the bond.

    I am wondering if there is any way that I can commercialize the solution, getting tired of others making money off my ideas over the years, and even get them phoning me to get my thoughts on how to solve their problems, and never even getting anything for it, but they get paid handsomely for "solving the problem"
    There is already a product intended to protect installations from floating neutral issues that detects an excessive voltage difference between neutral and earth. It is meant to be installed behind an earth leakage unit and protects the installation by causing the earth leakage unit to trip. I was thinking of something similar for this N-E bridging relay issue, but with a fault indicator light as signal.

    (I quietly wonder how many people with this new unit installed will be sitting there repeatedly trying to reset their earth leakage unit when this floating neutral protection device is activated because there is no indicator signal that it has been activated...)

  7. #17
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    If the neutral earth is that important, it should be done internally on all inverters and shut down the inverter automatically, with a built in fail safe mechanism, It should never be done externally, nor switched on the app.

    But hey I dont know what all the fuss is about on social media, if it was as dangerous as people make it out to be, the DOL would have published a formal document preventing the sale of these inverters in SA.

    Unfortunately it is going to take a death of a few people for anyone to issue a formal statement.

    Just remember the method you use is compliant until a formal statement is released. So if it takes another 5 years for the powers that be to issue a formal statement, your COC for the relay or permanent bond is still compliant.








    Quote Originally Posted by Justloadit View Post
    There is a simple way of knowing when there is no Neutral/Earth bond, in other words detecting lack of the bond.

    I am wondering if there is any way that I can commercialize the solution, getting tired of others making money off my ideas over the years, and even get them phoning me to get my thoughts on how to solve their problems, and never even getting anything for it, but they get paid handsomely for "solving the problem"
    Comments are my opinion, unless regulations are attached to support the comment. This is social media, not a court room.

  8. #18
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    You wonder why people dont fit ELU on inverter circuits

    You actually dont need a special device, or internal components, you just need to fit the device designed for public safety.



    Quote Originally Posted by Dave A View Post
    There is already a product intended to protect installations from floating neutral issues that detects an excessive voltage difference between neutral and earth. It is meant to be installed behind an earth leakage unit and protects the installation by causing the earth leakage unit to trip. I was thinking of something similar for this N-E bridging relay issue, but with a fault indicator light as signal.

    (I quietly wonder how many people with this new unit installed will be sitting there repeatedly trying to reset their earth leakage unit when this floating neutral protection device is activated because there is no indicator signal that it has been activated...)
    Comments are my opinion, unless regulations are attached to support the comment. This is social media, not a court room.

  9. #19
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    If the contactor is correctly sized for the neutral earth bond the chances of failure are extremely low - the same way that if a CB is sized correctly failure is low.

    If the contactor fails then the ELU will not work which according to statements made above should be tested regularly and so the fault would be picked up.

    How does the house owner test to ensur that his CB has not welded / failed - Is that not the same as the contactor ?

    How does he test to see that the eskom supply has not lost earth neutral bridge due to theft/burnt connection , over head line fault etc - That has been going for years

    I have mentioned it previously that the regs are written we need to comply - Not if you dont agree then make lots of noise on social media until it becomes so clouded in mystery that people purposely start ignoring the regs and so things never improve - same has euro socket

  10. #20
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    The comment about the ELU has nothing to do with the contactor/relay, if you do a permanent bond and fit an ELU on the input side of the inverter it will trip.

    You reply highlights why it is important to have the bridge done internally using a fail safe method.
    Comments are my opinion, unless regulations are attached to support the comment. This is social media, not a court room.

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