Hi there, I have an 8kw Sunsynk inverter installed and heard that on the older sunsynk inverters there is a neutral/earth issue and this can cause electrocution during load-shedding? I am very concerned as I have small grandchildren running around my house.

 

I am a granny so please explain in normal non-technical terms, please

 

Thanks 

 

Merlinda

Hi Merlinda, just for a little background; during loadshedding, the Neutral (N) and Earth (E) coming out of the inverter need to be bonded together for safety, but after loadshedding this bond needs to be automatically broken as Eskom provides a bonded N&E.

Most inverters have an internal mechanism to do this automatically, but the Sunsynk inverters usually don't so they need an external device to do the E/N bonding and unbonding and this should have been installed by your installer originally. Some installers will just permanently bond the N&E, but that is 'illegal' and dangerous.

If you could provide some images of your installation, there are quite a few professional installers on here like @Leshen, @Steve87 & @TaliaB who could help to identify if the necessary equipment has been installed correctly.

8 hours ago, jumper said:

Hi Merlinda, just for a little background; during loadshedding, the Neutral (N) and Earth (E) coming out of the inverter need to be bonded together for safety, but after loadshedding this bond needs to be automatically broken as Eskom provides a bonded N&E.

Most inverters have an internal mechanism to do this automatically, but the Sunsynk inverters usually don't so they need an external device to do the E/N bonding and unbonding and this should have been installed by your installer originally. Some installers will just permanently bond the N&E, but that is 'illegal' and dangerous.

If you could provide some images of your installation, there are quite a few professional installers on here like @Leshen, @Steve87 & @TaliaB who could help to identify if the necessary equipment has been installed correctly.

At last, someone has been able to explain the N&E in a way I can understand.

My geyser timer was tripping the earth when Eskom came back when the timer is on. This explanation helps me better understand why it stopped when I bypassed the timer.

Does the latest 8kw sunsynk inverter still not cater for this internally? 

No, none of the sunsynks cater for this. It's a design feature that a properly trained installer will know how to deal with. It's not a shortcoming that is not hidden. A competent installer should know how to make this machine operate safely. An Earth relay Bridge does the necessary to make the machine safe & the E/L will then be functional during loadshedding. 

Edited July 7, 20233 yr by Steve87

If one has everything on the essential load side does it still make sense to have the earth-neutral bridge because there's basically just one earth and one neutral and they're already bonded on the grid side? 

I think you should read this whole topic:

Inverter Neutral Earth bonding - Inverters - Power Forum - Renewable Energy Discussion

 

11 hours ago, solazzz said:

Does the latest 8kw sunsynk inverter still not cater for this internally? 

@solazzz I don't think that it is possible, the problem is that the Sunsynk & Deye work in two different modes with different Earth Bonding requirements.

Grid Attached mode - when the grid is active, the earth/neutral bond is provide by the grid

Island Mode - the earth neutral bond needs to be provided by the inverter. 

Because regulations vary from country to country it is not possible to have a earth/neutral bond built in that complies with all countries local regulations. 

• UK for example requires an inverter activated relay that disables the local bond when the inverter is connected to the grid and enables it when the grid is in Island mode.
• SA, depending on who you speak to, requires a permanent bond to be installed. (about 70% of installers seem to install this way according to a survey done on the Facebook groups). It is not 100% clear which is the "correct" way to comply with local regulations and there are arguments for both ways not complying.

The important thing is that your inverter has an Earth/Neutral bond.  

The fact that most Offgrid inverters come with a built in earth/neutral bond is one of the things that I think leads to some installers not installing them as they don't know that it is a requirement on the Sunsynk's and DEYE's

I made a video on the Earth/Neutral Bond, how to test etc.

Let me know what you guys think please, tried to make it as simple to understand as possible and hopefully didn't make any major mistakes 🙂 

I also tried not to take any sides as to which is the better way to have your Earth Neutral bond done as there seem to be proponents of both ways, I think the most important thing is that you have an Earth/Neutral bond in place. 

 

 

On 2023/07/08 at 7:22 AM, VirWat said:

I think you should read this whole topic:

Inverter Neutral Earth bonding - Inverters - Power Forum - Renewable Energy Discussion

 

Thanks. Will do.

9 hours ago, Sc00bs said:

I made a video on the Earth/Neutral Bond, how to test etc.

Let me know what you guys think please, tried to make it as simple to understand as possible and hopefully didn't make any major mistakes 🙂 

I also tried not to take any sides as to which is the better way to have your Earth Neutral bond done as there seem to be proponents of both ways, I think the most important thing is that you have an Earth/Neutral bond in place. 

 

 

Well done, and I hope your video reach far and wide. 

I personally wouldnt recommend a permanent bond, but you did qualify tbe method is open for debate and the user should approach  his/her installer. 

 

23 hours ago, Sc00bs said:

don't think that it is possible

Of course it is. GoodWe and Victron has internal N/E bonding relays. You also have to set the grid code to be compliant, so it is easy to change the functionality based on that. This also enables the inverter to test the relays and prevent operation in case of failure.

With the SunSynk, it seems they just repurposed the generator output, which also has additional delays that aren't ideal for safety when used as N-E bonding signal.

Edited July 9, 20233 yr by P1000

37 minutes ago, P1000 said:

Of course it is. GoodWe and Victron has internal N/E bonding relays. You also have to set the grid code to be compliant, so it is easy to change the functionality based on that. This also enables the inverter to test the relays and prevent operation in case of failure.

With the SunSynk, it seems they just repurposed the generator output, which also has additional delays that aren't ideal for safety when used as N-E bonding signal.

Thanks @P1000 , I wasn't aware that they are installing relays as I don't know the GoodWe or Victron inverters very well as I don't own one. 

I did also find this thread on the forum which sounds like this model specific Goodwe model doesn't bond the earth/neutral connection and there are some Victron models which also don't appear to have a relay to bond the earth/neutral.  I would suggest that people check their installations in any case, just to be safe, as it can be dangerous if they have a floating neutral.

My presumption was that the reason for not having an internal relay was perhaps because of compliance issues with local regulation varying in different jurisdictions making it impossible to have a solution that is compliant with  everyone and to rather leave it up to the installer to install a solution that complies. That could obviously be incorrect and it could just be them saving money and rather leaving that responsibility up to the installer🙂 , who knows, maybe we should ask Sunsynk/DEYE for the reason. 

2 hours ago, BritishRacingGreen said:

Well done, and I hope your video reach far and wide. 

I personally wouldnt recommend a permanent bond, but you did qualify tbe method is open for debate and the user should approach  his/her installer. 

 

Thanks @BritishRacingGreen, I must admit that I was a bit concerned because it seemed like a no-win situation. I felt that taking a neutral stance on the bond method and leaving the decision up to the installer issuing the COC would be the best approach.

Can you summarise the implications of not having the neutral bonded to earth?

How does this apply to products that use a 2-pin mains plug with no earthing facility?

3 minutes ago, chrisc said:

Can you summarise the implications of not having the neutral bonded to earth?

How does this apply to products that use a 2-pin mains plug with no earthing facility?

(A)You have a floating neutral(voltage between N-E above 5v.

1.RCD(earth leakage) will not function. 2.Electrocution in the event of earth fault.                                                    3.No COC could be issued.

(B)2 pin appliances is class II double insulated and has no reference to earth so without bond you are allowed to use only class II appliances.

Is it possible to test for the E/N bond by checking the EL trip switch in the DB board during load shedding?

Please excuse my ignorance 🙈

24 minutes ago, ZaydS said:

Is it possible to test for the E/N bond by checking the EL trip switch in the DB board during load shedding?

Please excuse my ignorance 🙈

No ignorance, in fact that is  a very very good question. 

The answer is actually NO. Its not  good enough. The test button on your ELD/RCD only affects a current imbalance, it does not prove that the  imbalance is due to Earth leaking current. 

If you do not have a plug tester, then use @Sc00bs plug/multimeter method as per his video. First prize is a plug tester that injects a proper leak to earth. If there is no bonding the ELD trip will not occur. 

EDIT : older models of ELD actually have an earth connection terminal on the ELD, so the test injected a leak to earth. If you ELD does not have this terminal, its a dead giveaway the test function cannot prove leak to earth. 

The cost of plug tester is not cheap, but ideally an owner of inverter should have one, and introduce a test evaluation on  at least monthly basis. 

Edited July 9, 20233 yr by BritishRacingGreen

13 minutes ago, BritishRacingGreen said:

No ignorance, in fact that is  a very very good question. 

The answer is actually NO. Its not  good enough. The test button on your ELD/RCD only affects a current imbalance, it does not prove that the  imbalance is due to Earth leaking current. 

If you do not have a plug tester, then use @Sc00bs plug/multimeter method as per his video. First prize is a plug tester that injects a proper leak to earth. If there is no bonding the ELD trip will not occur. 

EDIT : older models of ELD actually have an earth connection terminal on the ELD, so the test injected a leak to earth. If you ELD does not have this terminal, its a dead giveaway the test function cannot prove leak to earth. 

The cost of plug tester is not cheap, but ideally an owner of inverter should have one, and introduce a test evaluation on  at least monthly basis. 

https://leroymerlin.co.za/e-l-tester-with-remote-plug-5-35ma?sfdr_ptcid=32806_617_688431874&sfdr_hash=5268b98bf4ab1ec8b35ba5a85f7198ed&gclid=Cj0KCQjwtamlBhD3ARIsAARoaExPu3uSxCrVRvxCqKlc-3eetEcE-qmhC077rLjNlEGa9qPOHEmKH0saAtx3EALw_wcB

 

Above one from LeroyMerlin is good, for only 174 rand, and it even allows you to test the sensitivity of your ELD. 

Edited July 9, 20233 yr by BritishRacingGreen

39 minutes ago, BritishRacingGreen said:

https://leroymerlin.co.za/e-l-tester-with-remote-plug-5-35ma?sfdr_ptcid=32806_617_688431874&sfdr_hash=5268b98bf4ab1ec8b35ba5a85f7198ed&gclid=Cj0KCQjwtamlBhD3ARIsAARoaExPu3uSxCrVRvxCqKlc-3eetEcE-qmhC077rLjNlEGa9qPOHEmKH0saAtx3EALw_wcB

 

Above one from LeroyMerlin is good, for only 174 rand, and it even allows you to test the sensitivity of your ELD. 

Thank you. I’ll get one to make sure. 

2 hours ago, chrisc said:

Can you summarise the implications of not having the neutral bonded to earth?

How does this apply to products that use a 2-pin mains plug with no earthing facility?

My basic laymans understanding - perhaps @TaliaB or @BritishRacingGreen can confirm if I have made any errors? 

The electrical system in your house is designed for the Earth & Neutral to be bonded, as a result there is usually no risk of electric shock from the neutral and no protection is necessary on the neutral to earth circuit. Protection is only on the live - neutral via circuit breakers (over current) and live - earth via the earth leakage. 

When there is no bond you can get what is called a floating neutral and you can get a voltage difference between Earth & Neutral, sometime over 100V. As a result you can get an electrical shock with no earth leakage or circuit breaker protection if you make a neutral to earth circuit.   

One question for @BritishRacingGreen , from what you said earlier, it sounds like if the Earth Neutral are unbonded I can also get a shock from the  Live - Earth circuit, as there is no Earth leakage protection from an unbonded system, is that correct? 

Finally, I seem to remember reading somewhere that you can also get over voltages on the live as it is not tied to the earth and you can end up with +300V between Live - Earth, is that correct? 

 

1 hour ago, Sc00bs said:

My basic laymans understanding - perhaps @TaliaB or @BritishRacingGreen can confirm if I have made any errors? 

The electrical system in your house is designed for the Earth & Neutral to be bonded, as a result there is usually no risk of electric shock from the neutral and no protection is necessary on the neutral to earth circuit. Protection is only on the live - neutral via circuit breakers (over current) and live - earth via the earth leakage. 

When there is no bond you can get what is called a floating neutral and you can get a voltage difference between Earth & Neutral, sometime over 100V. As a result you can get an electrical shock with no earth leakage or circuit breaker protection if you make a neutral to earth circuit.   

One question for @BritishRacingGreen , from what you said earlier, it sounds like if the Earth Neutral are unbonded I can also get a shock from the  Live - Earth circuit, as there is no Earth leakage protection from an unbonded system, is that correct? 

Finally, I seem to remember reading somewhere that you can also get over voltages on the live as it is not tied to the earth and you can end up with +300V between Live - Earth, is that correct? 

 

@Sc00bs In South Africa we use   TN-C-S earthing system where T-terra(earth), N-neutral, C-combined,S- seperate. To futher explain this below illustration of the TN-C-S 3phase 4 wire system from transformer to supply kiosk on the walkway.

Incoming cable from kiosk to the house would be 3 wires LN and earth. The earth neutral bond is already made at point no 2. When entering your db board inside your house it now becomes "point of consumption" NO earth neutral bond should be made beyond the point of consumption again unless there is no incoming power from the kiosk(load shedding). Now you use a second power generation unit(inverter) that has a unbonded L N to earth so a new bond TN-C must be created for safety devices to operate within a specific time. That is the reason that when the first generation unit returns( Eskom) the second bond TN-S after point of consumption must be broken as the TN-C-S is complete again. The reason not to have a permanent bond after point of consumption is if the TN-C-S from the transformer should the neutral or Pen conductor be lost( stolen or broken) your bond after point of consumtion becomes the 200kva transformer earth/ neutral bond.

I suppose an easy way to check this is, when the mains power goes off, put an AC meter between N and E at the "Mains out" terminals of the inverter

12 hours ago, P1000 said:

Of course it is. GoodWe and Victron has internal N/E bonding relays. You also have to set the grid code to be compliant, so it is easy to change the functionality based on that. This also enables the inverter to test the relays and prevent operation in case of failure.

With the SunSynk, it seems they just repurposed the generator output, which also has additional delays that aren't ideal for safety when used as N-E bonding signal.

That was the thought that immediately flashed thru my mind - why not just install the relay and allow the installer to pick a setting. Finish and klaar.