Neutral/earth bridging method.

[Derlyn]

When bridging the neutral and earth on the inverter output during islanding mode, there are basically 2 ways of doing it and achieving the same result.

Which is the correct way and why ?

A. Use a normally open contact on the relay and energise the relay coil from the inverter output. Or.

B. Use a normally closed contact on the relay and energise the relay coil from the inverter input.


Edited 08.06am.

Ok, stupid question. Must be B. Inverter output is always there, whether in islanding mode or not so the relay will remain energised permanently.

[Isetech]

This is the reason both a relay and permanent bond are not the correct way to do it.

They are both just as dangerous and why, not having SABS approval in place prior to dumping these products in SA.

These units are not designed for the SA market and wouldnt have reached the SA shelves if there was still SABS approval required. I am surprised nobody has challenged the sale of these products.

To make matters even worse, the manufacturer just tells everyone they should do it as per the countries regulations.

So right now, anything goes and that is why people dont really care much for SANS regs.

If you decide to go with the relay and it fails, you are creating an even more dangerous environment for the user.

If this ever went to court, it would make for a really interesting court case, who would be responsible if someone was killed?

The manufacturer for dumping what some would be regarded as a dangerous product, I doubt them telling you on a youtube video to connect as per your countries regulations would cut it.

The supplier for selling this product without a a detailed document highlighting the dangers of these products?

The DOL for not taking steps to investigate these products and creating regulations to ensure the product is safe to install.

The installer who is not provided with a legal approved document clearly stating the dangers of this product and a detailed approved method to make it safe?

The fact that this subject is even being discussed on social media is a clear indication that there is a problem, so honestly If I were you I wouldnt worry to much about the a NO or NC relay, either way it is not safe until the inverters are designed and approved for sale in SA, with the required modifications to make them safe.

When bridging the neutral and earth on the inverter output during islanding mode, there are basically 2 ways of doing it and achieving the same result.

Which is the correct way and why ?

A. Use a normally open contact on the relay and energise the relay coil from the inverter output. Or.

B. Use a normally closed contact on the relay and energise the relay coil from the inverter input.


Edited 08.06am.

Ok, stupid question. Must be B. Inverter output is always there, whether in islanding mode or not so the relay will remain energised permanently.

[GCE]

This is the reason both a relay and permanent bond are not the correct way to do it.

They are both just as dangerous and why, not having SABS approval in place prior to dumping these products in SA.

These units are not designed for the SA market and wouldnt have reached the SA shelves if there was still SABS approval required. I am surprised nobody has challenged the sale of these products.

To make matters even worse, the manufacturer just tells everyone they should do it as per the countries regulations.

So right now, anything goes and that is why people dont really care much for SANS regs.

If you decide to go with the relay and it fails, you are creating an even more dangerous environment for the user.

If this ever went to court, it would make for a really interesting court case, who would be responsible if someone was killed?

The manufacturer for dumping what some would be regarded as a dangerous product, I doubt them telling you on a youtube video to connect as per your countries regulations would cut it.

The supplier for selling this product without a a detailed document highlighting the dangers of these products?

The DOL for not taking steps to investigate these products and creating regulations to ensure the product is safe to install.

The installer who is not provided with a legal approved document clearly stating the dangers of this product and a detailed approved method to make it safe?

The fact that this subject is even being discussed on social media is a clear indication that there is a problem, so honestly If I were you I wouldnt worry to much about the a NO or NC relay, either way it is not safe until the inverters are designed and approved for sale in SA, with the required modifications to make them safe.

So who is responsible when a CB welds in the closed position, or an Earth leakage unit does not work ?

[GCE]

When bridging the neutral and earth on the inverter output during islanding mode, there are basically 2 ways of doing it and achieving the same result.

Which is the correct way and why ?

A. Use a normally open contact on the relay and energise the relay coil from the inverter output. Or.

B. Use a normally closed contact on the relay and energise the relay coil from the inverter input.


Edited 08.06am.

Ok, stupid question. Must be B. Inverter output is always there, whether in islanding mode or not so the relay will remain energised permanently.

Most inverters have an output to operate the contactor

[Derlyn]

Thank you brother.

As always, a most comprehensive reply.

This particular inverter has a dry contact but is only for low battery.

The inverter has a sticker on it saying "South African Version".

I have not yet started it up yet, but will do so in a day or 2 and take readings. Who knows, maybe a bridge is not necessary on this unit. It's a Luxpower 5 Kw off grid inverter.

I will report back in a day or two's time.

Have a super day.

[Isetech]

We are talking about changing the state of a power supply, which could potentially create a dangerous environment, which might not be detected for weeks, month or years. I am sure you are aware that dangerous things require a fail safe mechanism or at least have some means of identifying that the relay has failed or arced closed.

If we have to fit some form of indications when the inverter is feeding the essential supply, a failed relay or permanent bond should be monitored. I am sure I have read that a permanent bond is dangerous, well I am sure a failed relay is just as if not more dangerous.

In my opinion, it should be fitted with a mechanism that is fail safe and shuts down the inverter until the danger is repaired.

By the way it clearly states on the ELU (the one I am holding my hand) "push monthly". Do you fit a label indicating that the relay should be checked daily to prevent injury if the relay fails ?

From my experience a CB would require a dead short or extremely high current to arc the contacts closed. If the cause of the fault is still connected you would attend to the problem.

So who is responsible when a CB welds in the closed position, or an Earth leakage unit does not work ?

[Isetech]

Some Sunsynk inverters are NRS 097 approved. (copied from the 12 kw 3 phase unit) no mention of the protection level class I or class II.


Certifications and StandardsGrid RegulationIEC 61727,IEC 62116,CEI 0-21,EN 50549,NRS 097,RD 140,UNE 217002,OVE-Richtlinie R25,G99,VDE-AR-N 4105EMC/Safety Regulation IEC/EN 61000-6-1/2/3/4, IEC/EN 62109-1, IEC/EN 62109-2

Some even have class I protection (copied from and 8 Kw installer manual) but no mention of NRS approval.

Protection Level Class I.

[Andrew_van_Zyl]

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.

[Sparks]

According to SANS neutral and earth may not be bonded after the point of control. After an installation I isolate the grid and take readings and if my readings are true I do not install a relay, I leave it as is. Relays often fail so unless you are going to test it on an ongoing basis you will end up with problems.

[Sparks]

Exactly, I am glad to see I am not the only one who is not happy about the current state of affairs. Well said.


"This is the reason both a relay and permanent bond are not the correct way to do it.

They are both just as dangerous and why, not having SABS approval in place prior to dumping these products in SA.

These units are not designed for the SA market and wouldnt have reached the SA shelves if there was still SABS approval required. I am surprised nobody has challenged the sale of these products.

To make matters even worse, the manufacturer just tells everyone they should do it as per the countries regulations.

So right now, anything goes and that is why people dont really care much for SANS regs.

If you decide to go with the relay and it fails, you are creating an even more dangerous environment for the user.

If this ever went to court, it would make for a really interesting court case, who would be responsible if someone was killed?

The manufacturer for dumping what some would be regarded as a dangerous product, I doubt them telling you on a youtube video to connect as per your countries regulations would cut it.

The supplier for selling this product without a a detailed document highlighting the dangers of these products?

The DOL for not taking steps to investigate these products and creating regulations to ensure the product is safe to install.

The installer who is not provided with a legal approved document clearly stating the dangers of this product and a detailed approved method to make it safe?

The fact that this subject is even being discussed on social media is a clear indication that there is a problem, so honestly If I were you I wouldnt worry to much about the a NO or NC relay, either way it is not safe until the inverters are designed and approved for sale in SA, with the required modifications to make them safe. "

[Derlyn]

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.

[Isetech]

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.

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.

[Isetech]

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.

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.

[Derlyn]

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 ".

[Justloadit]

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"