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How to install an earth rod for home and solar installation?


Islander

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Hi all,

I recently completed installing and wiring my home onto my solar installation. A bit rushed because the family was coming over to stay until over new years. Was able to finish on Christmas morning.

In any case, one of the things I need to do is install an earth still. Myself and my partner moved into this house just recently and there is no earth installed on the property so nothing is earthed.

I've read on the forum and seen on YouTube it's highly recommended to install an earth and ground your solar equipment in particular. 

So how best do I go about this? Considering nothing on the property is earthed of course. The panels are mounted on our roof which is corrugated iron. I'm quite ignorant still when it comes to electrics, learning as I go. Do I need to ground the roof as well as the panels and mounts for the panels? Thanks in advance for the help.

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I'm located in rural Mozambique, needless to say it's a bit of a wild west situation. This house was built by people who long since left, and has since been occupied by tenants who have each changed the wiring as they moved in. No one ever comes out this far to check things or enforce any kind of code, electrical or otherwise. 

 

Have not located an earth leakage breaker anywhere.

Edited by Islander
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3 minutes ago, Islander said:

I'm located in rural Mozambique, needless to say it's a bit of a wild west situation. This house was built by people who long since left, and has since been occupied by tenants who have each changed the wiring as they moved in. No one ever comes out this far to check things or enforce any kind of code, electrical or otherwise. 

 

Have not located an earth leakage breaker anywhere.

Sorry to hear this as it means you in for a long haul. We will try and assist but I would guess the best is to try and locate where the power comes into the property as the main supply. 

Getting an E/leakage is a priority for safety. 

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In my case the installer first dug a trench about 50cm deep 5m long, then bashed 3 copper rods 1.5m long about 1.5m apart into the ground.
Covered them and connected them to a N/E bond relay for when running in Island mode.

Edited by system32
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3 minutes ago, Scorp007 said:

Sorry to hear this as it means you in for a long haul. We will try and assist but I would guess the best is to try and locate where the power comes into the property as the main supply. 

Getting an E/leakage is a priority for safety. 

Yes indeed, if no earth on your DB, you need to create an earth, if you cannot find an earth rod, in the interim time get yourself one or two old car radiators, dig a hole +_1 meter deep, that should do. I know what you are talking about I've lived in Mozambique and Angola, there is no such a thing as SOC in electrical installation. Everyone for himself and the rest for the devil.

 

 

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Yes this is exactly the situation @Antonio de Sa. Will try to answer everyone with this post.

As for where the power comes into the house, firstly, we're on an island. So that used to be where the generator was, which I have since disconnected since moving in. I have now installed a solar setup, with a backup generator as well. Rewired the entire property before installing the solar to make sure that I don't stuff up my equipment as the previous tenant didn't look after anything. Bare live wires everywhere, joined wires near a thatch roof, wires running through thatch, and no sign of conduit anywhere.

As money comes in I am trying to improve on this but for now I've done the best I can with what I have. I also am not an electricians backside so again, there's a learning curve here that I'm trying to adjust to to make sure things are done properly and safely.

I'm not sure what an N/E bond relay is or how it would function so I will research this. 

I have a couple of metal rods and pipes, any guidance on which would be the best to use as the earth rod?

My understanding right now is as follows:

I would dig a hole, bury the respective pipe or rod, connect a wire to it, and then run that wire to my DB board, connect that to the earth bus, and then make sure all earth busses in the house on each of the DB boards are connected back to the main DB board earth bus? 

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12 hours ago, Islander said:

Yes this is exactly the situation @Antonio de Sa. Will try to answer everyone with this post.

As for where the power comes into the house, firstly, we're on an island. So that used to be where the generator was, which I have since disconnected since moving in. I have now installed a solar setup, with a backup generator as well. Rewired the entire property before installing the solar to make sure that I don't stuff up my equipment as the previous tenant didn't look after anything. Bare live wires everywhere, joined wires near a thatch roof, wires running through thatch, and no sign of conduit anywhere.

@Islander

I would recommend using conduit to run all the wiring or if you can get surfix cable ( 2 wire + earth ) would be fine. use 1,5mm2 for lighting and 2,5mm2 for all your plugs, also use cable glands on all your sockets, lights, DB etc...

The AC output of your inverter should feed a 32 Amp earth leakage

 

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As money comes in I am trying to improve on this but for now I've done the best I can with what I have. I also am not an electricians backside so again, there's a learning curve here that I'm trying to adjust to to make sure things are done properly and safely.

I'm not sure what an N/E bond relay is or how it would function so I will research this. 

You don't need N/E bond relay, you are not connected to the grid.

I have a couple of metal rods and pipes, any guidance on which would be the best to use as the earth rod?

Metal rods, depending on the diameter, water pipes 20mm should do, cut them to about 1 m, 3 or 4 of them spaced about a meter apart stuck to the ground and run at least 6mm2 wire to your DB, taking in consideration that you live in an island the water table should be quite high you should be able to get a good earth.

You can test it by using such a device, costs about R 700, anything bellow 5 ohms would be ok, 0 ohms is the ideal, but for house wiring 5 ohms is OK

shopping?q=tbn:ANd9GcRwn86ghzIjQ0yFVC9zerTkE3oF5xNOaD2LmOwHTLHXuzVYD8KMltjPlyp_IKlrMvOZBjKG6IXRgpOkCkvVe28iPeUAHkWjZjcvtbWJSGtE5weUF-L9nWw0&usqp=CAE

My understanding right now is as follows:

I would dig a hole, bury the respective pipe or rod, connect a wire to it, and then run that wire to my DB board, connect that to the earth bus, and then make sure all earth busses in the house on each of the DB boards are connected back to the main DB board earth bus? 

 

 

Edited by Antonio de Sa
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I needed to have an additional earthing rod installed for my inverter installation.

The specifications of the earthing rod is as follows, 1.5m in length, M15 thickness. Peg into the ground about 10meters away from the inverter or db board) as deep as it goes, so there is enough threading left to attach the earthing cable. Example of earthing rod (https://www.acdc.co.za/products/1-5m-x-m16-earth-rod-150-microns-copper?variant=30477844364)

 

The N/E bond relay is also dependent on your inverter, the inverter will need to signal the relay to engage to create the bond. The Sunsynk has a control terminal for this and I also needed to have this installed. If you do not have grid power the odds are that you will need to bond the N/E permanently as the relay is only needed on my inverter when the grid is offline.

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41 minutes ago, JuliusK said:

I needed to have an additional earthing rod installed for my inverter installation.

The specifications of the earthing rod is as follows, 1.5m in length, M15 thickness. Peg into the ground about 10meters away from the inverter or db board) as deep as it goes, so there is enough threading left to attach the earthing cable. Example of earthing rod (https://www.acdc.co.za/products/1-5m-x-m16-earth-rod-150-microns-copper?variant=30477844364)

 

The N/E bond relay is also dependent on your inverter, the inverter will need to signal the relay to engage to create the bond. The Sunsynk has a control terminal for this and I also needed to have this installed. If you do not have grid power the odds are that you will need to bond the N/E permanently as the relay is only needed on my inverter when the grid is offline.

@JuliusK   According to what I read on top there is no grid supply to the premises. So, no need for N/E bonding regardless of what type of inverter.

Yes, would be nice to have an earth rod, but he does not have one, the solution I propose will work in the interim time, also suggest getting it tested. My friend I've lived in places in Africa where you have to do with what is available. I know what I'm talking about it, it worked for me, even using old car radiators. but I have to add, I had the necessary instrumentation to measure it. 

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11 minutes ago, Antonio de Sa said:

@JuliusK   According to what I read on top there is no grid supply to the premises. So, no need for N/E bonding regardless of what type of inverter.

Yes, would be nice to have an earth rod, but he does not have one, the solution I propose will work in the interim time, also suggest getting it tested. My friend I've lived in places in Africa where you have to do with what is available. I know what I'm talking about it, it worked for me, even using old car radiators. but I have to add, I had the necessary instrumentation to measure it. 

Apologies not trying to start a fight. Just quoting from my experience. 

 

I also had a chat to my dad who's an electrical eng about the earthing. To properly create an earth you would need at least 3 earthing rods but depending on what kind of material you have on the ground. If it's sand you may need up to 10 earthing rods. 

So at a pinch your design may work but as you said you need to get it tested. The earthing should be below 10ohms (best case scenario). 

Good luck! Exciting build! 

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17 minutes ago, JuliusK said:

Apologies not trying to start a fight. Just quoting from my experience. 

 

I also had a chat to my dad who's an electrical eng about the earthing. To properly create an earth you would need at least 3 earthing rods but depending on what kind of material you have on the ground. If it's sand you may need up to 10 earthing rods. 

So at a pinch your design may work but as you said you need to get it tested. The earthing should be below 10ohms (best case scenario). 

Good luck! Exciting build! 

@JuliusK I did not say anything about a fight, we don't fight in this forum. I simply stated facts that I had encountered in my professional life. It worked for me, I tested, and I've always aimed to get at the most 5 ohms for any house wiring, sometimes depending on the type of soil one may need 3, 4 of whatever is available, we are not talking about an earth system for a data center where you would aim to 0 ohms.

Edited by Antonio de Sa
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I hammered a 1.8m long earth rod into the ground, in a south east, shaded corner outside my house where the soil is always damp. If your soil is soft you can connect 2 rods together for a better deeper earth. 

I used 10mm² cable to connect all the panels together, connect panels to frames, frames to roof sheeting. 10mm² from db to inverter and earth neutral bond relay. 

I then bolted all that cables to a start point on a "ground clean/paintless" roof sheet and from there used 16mm² earth cable to the earth pin.

It is preferred to use as thick as possible earth cable, double or more than your supply cable. 

I installed another pin where the municipality grid enters my house after previous earth problems with grid supply.

I would install an earth cable from the generator to the earth pin also. 

NB the only device to protect you as user is the earth leakage. For your own safety, install one asap and test it oftenly.

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