Hi there, I am new and thanks for opening this forum for novice questions. I am installing a new 3,5KV Fivestar hybrid inverter with 2 x 120ah batteries and 2x390w panels. The installation (with the help of an electrician) went well and everything makes the right noises, etc. I have a small DB (from the panels) with surge arrestors, fuses and circuit breaker) leading to the inverter. From inverter, circuit breaker leading to the batteries. From the inverter to the main DB (SPDs, main circuit breaker, contactor, earth leakage and then 20A breaker for the plug outlet).

I get the following reading: L to N = 220v, L to earth = 220v and Earth to N = 0v. All wiring was checked and checked again. Now, as soon as I connect anything to the plug outlet, the Earth leakage trip. I changed the plug outlet and the wire. Keep in mind this is not connected to Eskom, it’s completely separate.

Me dunno anymore….

11 hours ago, Freddievanleeuwen said:

get the following reading: L to N = 220v, L to earth = 220v and Earth to N = 0v

EDIT: Ok, ignore some of my questions below, just realized you are not connected to Eskom, apologies. 

 

11 hours ago, Freddievanleeuwen said:

 

[deleted. Irrelevant] 

11 hours ago, Freddievanleeuwen said:

 

[deleted. Irrelevant] 

Edited March 4, 20233 yr by BritishRacingGreen

59 minutes ago, Freddievanleeuwen said:

Hi there, I am new and thanks for opening this forum for novice questions. I am installing a new 3,5KV Fivestar hybrid inverter with 2 x 120ah batteries and 2x390w panels. The installation (with the help of an electrician) went well and everything makes the right noises, etc. I have a small DB (from the panels) with surge arrestors, fuses and circuit breaker) leading to the inverter. From inverter, circuit breaker leading to the batteries. From the inverter to the main DB (SPDs, main circuit breaker, contactor, earth leakage and then 20A breaker for the plug outlet).

I get the following reading: L to N = 220v, L to earth = 220v and Earth to N = 0v. All wiring was checked and checked again. Now, as soon as I connect anything to the plug outlet, the Earth leakage trip. I changed the plug outlet and the wire. Keep in mind this is not connected to Eskom, it’s completely separate.

Me dunno anymore….

Ok lets try again :

Your setup is so straightforward, no grid, one plugpoint, that the only thing that comes to mind is a faulty ELD. 

What is the purpose of the contactor? 

 

 

Tested the EL, working fine. Added the contactor due to N to earth being 70v and L to earth around 140v.

The only power supplied, coming in is from the panels. No eskom. The AC out goes to the main db where the connection to the breaker for the plug point is. I will test tomorrow with the panels on and off to see if there's a difference.

Right, so the first thing you need to do, is you need to tie the earth of the inverter to the same earth used for the rest of the electrical system. If it is really truly off-grid (no escom electrical supply) this may involve sinking 2 x earth spikes into the ground and making sure the impedance is below 20 ohms. Then you have to bond the neutral and the earth together where it leaves the inverter (before the RCD).Then you feed this live and bonded neutral lines into your RCD in the usual fashion, and that's it. Any earth fault after the RCD should cause an imbalance and trip.

After installing your earth rods the electrician must do a earth fault loop impedance test at the inverter input and the same test at the socket outlet.

 

Also tie your solar panels metal parts to the same earth rods

9 hours ago, Freddievanleeuwen said:

Tested the EL, working fine. Added the contactor due to N to earth being 70v and L to earth around 140v.

The FiveStar inverter being a Voltronics clone should have a bonding relay already built in. Did you earth the inverter with the local earth? 

You can test this bonding function by removing all supplies to the inverter (remove wires from terminals) , then check for continuity between the inverter output neatral and its  earth terminal. If there is continuity the bonding is already in place. But then you must ensure to wire the local earth to the machine. This illiminates the need for an additional bonding contactor. 

Also, as you have it now, does the existing contactor bonds the neatral to earth  before the ELD? 

EDIT: in the event where you dont have bonding built in the inverter, you can still get away with a permanent neatral to earth bond in your db box. This is because you not using a grid input at all.  But you must still earth the inverter as well. So there is no use for the contactor so you can remove it. 

 

Edited March 4, 20233 yr by BritishRacingGreen

Thanks for the feedback . I will reply as I check the different options.

10 hours ago, TaliaB said:

Right, so the first thing you need to do, is you need to tie the earth of the inverter to the same earth used for the rest of the electrical system. If it is really truly off-grid (no escom electrical supply) this may involve sinking 2 x earth spikes into the ground and making sure the impedance is below 20 ohms. Then you have to bond the neutral and the earth together where it leaves the inverter (before the RCD).Then you feed this live and bonded neutral lines into your RCD in the usual fashion, and that's it. Any earth fault after the RCD should cause an imbalance and trip.

After installing your earth rods the electrician must do a earth fault loop impedance test at the inverter input and the same test at the socket outlet.

 

Earth from the inverter is tied to the systems earth via a spike in the ground. The contactor is located between the main switch and the EL (which I assume is the RCD). I still have to check the impedance.

57 minutes ago, Freddievanleeuwen said:

Earth from the inverter is tied to the systems earth via a spike in the ground. The contactor is located between the main switch and the EL (which I assume is the RCD). I still have to check the impedance.

@Freddievanleeuwencan you send me a drawing of your wiring system as i don't understand the purpose of the contactor between the main switch and the earth leakage (RCD residual current device). Your earthing system needs to have continuity right throug the wiring system from your earth spike to your output socket. Ask your electrician to check with a milliamp clamp meter at the bottom of the earth leakage around the live and combined earth neutral to see what the current reading is. It should not exceed 10ma without any load plugged in 

So this is now an emergency... If you think it cannot get any worse, the Eskom transformer outside on the road just gave in. I have 50v to my house. 🥵

54 minutes ago, TaliaB said:

@Freddievanleeuwencan you send me a drawing of your wiring system as i don't understand the purpose of the contactor between the main switch and the earth leakage (RCD residual current device). Your earthing system needs to have continuity right throug the wiring system from your earth spike to your output socket. Ask your electrician to check with a milliamp clamp meter at the bottom of the earth leakage around the live and combined earth neutral to see what the current reading is. It should not exceed 10ma without any load plugged in 

OK. I will send a picture and wait for him to check this. We live in a remote area.

Hi Freddie. It sounds like your earth and neutral on the plug circuit may be shorted somewhere. Please indicate all the points in your house where earth is connected to a neutral.

Hi Freddie. I Would recommend changing that e/l to a Type A(IR) Gewiss Earth leakage (GWD4208). They are bit expensive, but worth it. The Kingstar is no good. The type A(IR) earthleakage helps especially when there are possible pulsing DC current present and also has a greater resistance against surges and atmospheric discharges. Also the contactor move you have going on there to connect neutral to earth I am unsure about. Disconnect that for now and make sure your incoming neutral and earth from Eskom or your main earth from your earthing network is properly bonded. It can be as Frivan says, but sound to me like a DC pulse issue. Also test your earth continuity, must be below 0.5ohm, but try getting it as close to 0 as possible by implementing trenched earths.  Also, take a clamp on meter and measure if any current is present on your incoming earth conductor when your inverter is supplying any load. There should be none or very little. If there is any. improve your earthing. Are your pv panels grounded to negative? make sure that is not the case.

45 minutes ago, RedDragon said:

Hi Freddie. I Would recommend changing that e/l to a Type A(IR) Gewiss Earth leakage (GWD4208). They are bit expensive, but worth it. The Kingstar is no good. The type A(IR) earthleakage helps especially when there are possible pulsing DC current present and also has a greater resistance against surges and atmospheric discharges. Also the contactor move you have going on there to connect neutral to earth I am unsure about. Disconnect that for now and make sure your incoming neutral and earth from Eskom or your main earth from your earthing network is properly bonded. It can be as Frivan says, but sound to me like a DC pulse issue. Also test your earth continuity, must be below 0.5ohm, but try getting it as close to 0 as possible by implementing trenched earths.  Also, take a clamp on meter and measure if any current is present on your incoming earth conductor when your inverter is supplying any load. There should be none or very little. If there is any. improve your earthing. Are your pv panels grounded to negative? make sure that is not the case.

Sorry but if you read the orginal post from @Freddievanleeuwenthere is no eskom on this installation off grid or am i confused. It is very diffucult to see what is actually going on with the wires running all over the show due to the unconventional layout of the new ac panel how it should be main switch on the left, earth leakage right next to it then the load breakers then the spd's. It almost looks like the neutral wire at the bottom of the earth leakage is running to the output of the inverter i could be wrong like i said diffucult to see. Freddie hopefully you didn't pay this electrician already as i would make him fix his mess. Also the dc wires should not run through the ac panel he must fix that as well. The way i understand it being off grid system your inverter needs to be bonded right at the output of the inverter it should already have a bonding relay in the inverter like @BritishRacingGreensaid.  The output of the inverter should run to the top of the main breaker the bottom of the main breaker to the top of the earth leakage the bottom of the earth leakage live to the top of the single output breakers and the neutral from the earth leakage to the neutral bar from neutral bar to socket outlet.You have a wiring fault somwhere in that panel. Just tell me the red and black 2.5mm² wire runs to the inverter output? and the 1.5mm²red blue to your plug socket?

Edited March 4, 20233 yr by TaliaB

@Freddievanleeuwenyou can show the electrician this is how an ac panel should be wired + the spd's to the right.

 

 

Thanks for the info everyone. Let me take all this info one bite at a time. I will revert.

 

4 hours ago, frivan said:

Hi Freddie. It sounds like your earth and neutral on the plug circuit may be shorted somewhere. Please indicate all the points in your house where earth is connected to a neutral.

So I only have the 1 new plug point that was fitted. I changed the point as well as the cable.

1 hour ago, TaliaB said:

@Freddievanleeuwenyou can show the electrician this is how an ac panel should be wired + the spd's to the right.

 

 

Those sharp 90 deg angles have surely compromised the integrity of the insulation and most likely damaged and cracked the copper inside. The cables now have much less conductivity and the insulation much less protection. That's surely how a panel should NOT be wired.

21 minutes ago, PowerUser said:

Those sharp 90 deg angles have surely compromised the integrity of the insulation and most likely damaged and cracked the copper inside. The cables now have much less conductivity and the insulation much less protection. That's surely how a panel should NOT be wired.

You are definetly not a installation electrician what the ...... how in a million years can you crack multicore gp cable and less conductivity rather not comment if it is not constructive

2 hours ago, TaliaB said:

Sorry but if you read the orginal post from @Freddievanleeuwenthere is no eskom on this installation off grid or am i confused. It is very diffucult to see what is actually going on with the wires running all over the show due to the unconventional layout of the new ac panel how it should be main switch on the left, earth leakage right next to it then the load breakers then the spd's. It almost looks like the neutral wire at the bottom of the earth leakage is running to the output of the inverter i could be wrong like i said diffucult to see. Freddie hopefully you didn't pay this electrician already as i would make him fix his mess. Also the dc wires should not run through the ac panel he must fix that as well. The way i understand it being off grid system your inverter needs to be bonded right at the output of the inverter it should already have a bonding relay in the inverter like @BritishRacingGreensaid.  The output of the inverter should run to the top of the main breaker the bottom of the main breaker to the top of the earth leakage the bottom of the earth leakage live to the top of the single output breakers and the neutral from the earth leakage to the neutral bar from neutral bar to socket outlet.You have a wiring fault somwhere in that panel. Just tell me the red and black 2.5mm² wire runs to the inverter output? and the 1.5mm²red blue to your plug socket?

I received the box with the breakers in that order.

3 hours ago, TaliaB said:

@Freddievanleeuwenyou can show the electrician this is how an ac panel should be wired + the spd's to the right.

 

 

You practically do not need a circuit diagram. Its very well crafted. 

1 hour ago, TaliaB said:

You are definetly not a installation electrician what the ...... how in a million years can you crack multicore gp cable and less conductivity rather not comment if it is not constructive

Sharp bends

This probably won’t come as a surprise, but sharp bends are never good for wires. They can result in broken strands in the conductor, and they put a lot of stress on the insulation. In some cases, the insulation may even buckle if the wire is bent sharply enough, especially in the case of a tape-wrapped wire. Wires with extruded insulations tend to perform better in applications where sharp bends are necessary, but even extruded insulations have their limits.

In the mechanical engineering world, engineers are taught to avoid sharp 90-degree bends in the components that they design in order to avoid large stress concentration factors in those components. A stress concentration factor quantifies how concentrated the stress is in the highest stress region within the part, due to its geometry. Parts with sharp 90-degree bends in them are considered to have a stress concentration factor of 4.35 at the corner, meaning that the stress at the corner of the component is about 4.35 times higher than the average stress throughout the rest of the component.

In wire terms, this means that the copper and the insulation both see significantly higher stresses wherever sharp bends are made. This can lead to mechanical failure in one or both. If you have ever seen a cordset or charging cable where the jacket has been damaged where the cable enters the strain relief, exposing the insulated conductors, that’s a perfect example of this type of damage. A sharp bend in the wire at the entrance to the strain relief would be the most likely cause of the failure.

Source:

https://www.rubadue.com/technical-info/tips-on-how-to-avoid-damaging-insulated-winding-wires-in-your-process/