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This is an explainer podcast on how I setup the earthing system for my off-grid solar protect
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Off-grid Solarearthinggrounding
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This is an explainer podcast on how I setup the earthing system for my off-grid solar protect
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The speaker discusses the topic of earthing and shares their own experience setting up an electrical system. They emphasize the importance of understanding the purpose of earth and how it provides a path of least resistance for electricity to go to ground. They explain the connection between the neutral and earth bars in a distribution box and how electrical appliances are automatically grounded when plugged into sockets. The speaker also mentions the dangers of faults, where live wires come into contact with the chassis of appliances, and how proper earthing can prevent accidents. They explain the concept of electricity following the path of least resistance and how a proper earthing system can ensure the safe return of electricity to the source. They mention the use of safety devices such as circuit breakers and RCDs to protect against electrical hazards. The speaker acknowledges the presence of misinformation and the importance of seeking professional advice when needed. The way I feel about a lot of the conversation that has been going on in the forum concerning earthing is that it's not that deep, and I know that there's been a lot of information, and this feels like information overload, but I just want to talk about how I had my own system set up, and maybe people can pick one or two things and use that in setting up their setup. So a bit of a background, as usual, I'm not an engineer, I'm not an electrical engineer, a lot of what I've learned, a lot of what I'm talking about is just from things that I've learned, and watching lots of videos, reading up on these things, and trying to just understand the basic concept, and using that knowledge in setting up my system, and once I set up the system, I just reach out to people, and just show them this concept to see, okay, how good is it? Sometimes I go online, and I just lay out, this is my system set up, and allow people to just openly criticize it, and especially places where you have lots of engineers, and I realize that doing that helps me to just get better. Now, one thing I want people to know is that it's really, really hard to get professionals who are actively practicing, who know, who have very core, fundamental knowledge of these things. If you get in a lot of the electricians in practice, even some of the best of them will tell you things that immediately you'll find it as shocking. I remember an engineer telling me that the connection to your air throat should not be more than four mm cable, and he was defending it, and he was saying if you use something higher, it's gonna be bad. You have a lot of misinformation out there, and if there were clarity, and if you have professionals, trust me, that is one aspect of my DIY system that I would rather just leave to professionals, and just allow professionals to handle, but that's not the case, and at the end of the day, you just have to do these things. You can't just leave them. You just have to do it, and in my case, I just went with, just took a lot of the information that I've acquired in setting up a system, so the first thing first is what does earth do? What's the essence of earth, and I think that's the most important questions to ask. From everything I've read, earth can do quite a number of things. Earth is there to provide a path of least resistance for electricity to go to ground, and this is one of the characteristics of electricity is that it's always following the path of least resistance to ground, and so by having your earth rod buried in the ground, in the soil, in your compound, you provide that path of least resistance. If you go to your DB, electrical DB, you will see that there are three, two major bars. You have your neutral bar, and then you have your earth bar. The life wire goes into your circuit breakers, so all the neutral in the socket in your house, every one of them is wired off to the DB, and the same thing for the earth. The earth part of your socket is the top one. If you have a three-pong plug that we use in Nigeria, the top part is the earth, so that means that all the socket, when you plug in an electrical socket into your house, that electrical socket is also automatically grounded. It's also connected to earth because at the end of the day, it finds its way to the DB, and so that DB, that earth bar in your DB that connects to all the sockets in your house, that earth bar, there is a cable that runs from that earth bar and goes to your earth rod. I mean, that's the idea. That goes to your earth rod so that if there is a fault, there's a fault. What is a fault? A fault is where maybe you have a life wire connecting to the chassis of one of your equipment, and this happens a lot. When I was growing up, I used to be afraid of fridge and freezers because I used to hear stories of people just getting electrocuted, like you touch your fridge, and then it just kills them straight. I mean, I used to be terrified of these stories, and I don't know, maybe you heard about them too. So, let's say you have your fridge. I'm gonna use the fridge as an example here. Let's say you have your fridge, and for some reason, one of the life wires of your fridge touches the body of the fridge. Now, the body of the fridge is made of metal, and if it touches the body of your fridge, which it's not supposed to, that's a fault. So, if it touches the body of your fridge, the fridge will continue to work, but the body of your fridge is now life, now contain life, electricity. And you know, electricity work in a circuit. Electricity is trying to return back to the transformer. It's trying to return back to the transformer, back to source. It's a circuit. It's supposed to go from the life wire, go to your electrical power, your electrical appliance, and then return to the neutral wire, back to source. So, it's trying to make that circuit, okay? Now, the body of the chassis is wet. If you go there, say you go there, you know, then they say, okay, if you don't wear suit parts and stuff, let's say you're not wearing suit parts, so you're connected to ground, you are standing on the ground. That electricity, when you touch the freezer, the electricity will then use your body, try to use your body to make that ground connection, to connect to ground. They try to make your body to connect to the ground and try to return back to source. Now, hold that thought, and I will explain to you why would it want to use your body to return back to source? Why would they want to use your body? And what does return back to source mean? So, from what I understand, I'm gonna explain it to you. So, in that process, you get electrocuted and you may die. Now, let's say you have a proper heating system. You have a proper heating system, like an H-rod installed in your house. What would happen is, instead of, because the body of that freezer is already connected to the earth, remember we talked about the three-pong plug that everybody uses? The top of that plug is up. Now, when you plug that freezer into your socket, the top part connects to the earth bar in your installation, that is, in your distribution box, and that earth bar connects to your H-rod. So, what happens is that, because the chassis of that freezer connects to the top-prong earth, that earth connection that is in your freezer plug, the body of your freezer uses that connection. They connect it to the body of your freezer, and they do this because they know that a fault might happen. So, the body of your freezer is connected to your H-rod, physically, through the internals of the freezer, connects to the top-prong of your plug, from the top-prong of your plug connects to your DB, from your DB connects to your H-rod. And because that connection is made, and remember, we say electricity follows the path of least resistance. The human body is not very resistant. I mean, it's not, it's high resistance. Even though, I think I read somewhere that it has about 1,000 ohms of resistance. So, that's a very, very high resistance for electricity. Because you've connected it to a better path, which is through your H-rod, through your DB, and preferably you use copper wire and all of that, that electricity will follow that path, will take that path to return to source. Now, what does returning to source mean for the electricity? I mean, you may say, well, my electricity wasn't, like, my electricity wasn't invented on the ground, so how is it returning to source? My electricity came from NEPA, so why is it returning to the ground? And the answer is simple. Under a TT system, essence system, which is what we use where we install the H-rod, the neutral that the NEPA supplies to your house, that the grid supplies to your house, that neutral, at the transformer, where that neutral comes from, where the neutral comes from, the neutral comes from your transformer. The transformer that supplies your house, that transformer is earthed, is grounded. There is an H-rod on the ground that has been installed in that transformer. And the earth wire of that transformer is bonded to your neutral, is connected to your neutral, is physically connected, they tie them together, like, they bond them together, right? So that the earth of your transformer and the neutral of your transformer are essentially one and the same. So the neutral that's supplied to your house is essentially the earth of the transformer, because they are physically bonded. And the idea is this. Your H-rod, the one you install in your house, it will then use the ground, the soil, the soil between your house and your transformer, it will use that soil, because soil can conduct electricity. I mean, that's the logic behind H-E-T system. It will use that soil to connect back to the transformer, which in this case, the neutral. You know, electricity is supposed to go from life, connect to your appliances, and then use the neutral, and then return back to source, to network. But because your life touched the body of your appliances, so because it touched the body of your appliances, right, of your freezer, in this case, and the freezer is connected to your ground, so it goes from the body, it touches the body of your freezer. From there, it goes to the distribution board, and then from the distribution, the head by your distribution, it goes to ground. And then from ground, it connects back to the neutral of the transformer. So it has made a complete circuit. And in doing that process, you have some safety devices, like your circuit breaker. In completing that route, it trips, because of the, depending on how resistant your earth rod is. But because in order for you to have a flow of electricity, to trip a breaker, it's not easy. So in order to help it along, that's why you have an RCD, or when we talk about RCCB or RCBO, that's why you have an RCD. So what an RCD does is that, an RCD measures what goes in from the life, that is from your, that's where you install the RCD is, at your consumer unit, that is from NEPA into your DB. And from your DB, before it start connecting to your house, it goes through an RCD, connects to the neutral and connects to the life. The neutral goes to neutral, the life goes to life. So what the RCD does is, it checks that, okay, in this house, I turn on a light bulb. It sees that, okay, five watt comes out through life, and five watt returns back through neutral. So it knows that all is okay. But if five watts, in the case of this freezer touching the chassis of your fridge, it sees that five watts, and it touches the chassis of your fridge, and it's now following your ground, following your ground, that is your etch rod back to source. It's not following neutral. And so if in that five watts released from life, but it doesn't come back to neutral because that wire in your freezer is touching the body. And because it's touching the body of your freezer, it is then using that body of the freezer to find its way to your ground, and then find its way back to source. And in doing that, the RCBO says, oh, five watt left this thing. Why is it nothing is returning? So the RCBO trips, the RCD trips. So in tripping, it disconnects and ensures that that fault does not hurt anyone. And so there's a protection system. So that's part of what the earth is. The earth is supposed to provide a path back to NEPA, back to source, in case there is a fault. So that's one of the key aspect of an etch rod. The other aspect of an etch rod is that in case of a surge, maybe the surge is coming from NEPA, it's coming from indirect lightning and all of that. Like when there is a surge, an indirect lightning in your area, every metal, every exposed metal around your house, this could be your satellite dish, it could be a solar panel, it could be anything exposed outside of your house. In my office, it was a CCTV. They get a very high surge of voltage, especially the metal part of it, because that surge creates induced voltage. And I don't know if I'm using the right word, but you can just see like all of them get very high number of voltage. And again, electricity is looking for a way to ground because you've grounded, you have an etch rod and every part of your system is grounded. If that surge comes into your house, if you have an SPD, that's where an SPD comes in, a source protection device, which you install in different entrance points of your house. So for example, I have an SPD installed on my solar panel, incoming wires, and I've explained how I set it up. So basically, you have the positive and negative of my solar array. They connect into a series of breaker. And when you connect wires to the breaker, the wire exits from the breaker. At the exit point of that breaker, the SPD has a positive, negative, and third. So I connected the positive of the SPD to the positive of the output from that breaker. And I connected the negative of the SPD to the negative of the output of the breaker where my solar PV cables are coming from. And then I connected the earth of the SPD to my ground, my system ground, which is the system ground that leads to the etch rod. So that when a surge, if there is a surge condition and it's bringing very, very high surge electricity, very high current, very high voltage electricity into my installation. When that thing gets to this SPD, the SPD is a special kind of device, right? It has something called a varistor. And that varistor, once it senses high voltage, it becomes a very low resistant device. It becomes a very, very low resistant device. And because it's a very low resistant device, it attracts the electricity to itself because it becomes very low. On a normal condition, it's a very high resistant device because it's not a fault condition. And you have your SPD on a normal day. It's just normal, high resistant, very high resistance. It allows electricity to pass through. So because it connects to the outputs of your breaker, the breaker that protects, that sits in between the wire coming from your solar panel. So you have positive from the solar panel connects to the positive of the breaker, plus negative of the solar panel connect to negative of the breaker. And then it has to exit in order for it to then connect to maybe your inverter or your charge controller. Now that exit point, which is called the load point of your circuit breaker, that is where your SPD connects to. It just takes the wire and just connects to them so that it's in line, right? It connects in line, or you could just say that it connects in parallel, right? To the two positive and negative. And so the idea by connecting in parallel, it's monitoring that situation. If there is a surge, it becomes a low resistance, so low that it attracts that source to itself and then send it down to ground. And in essence, protecting your installation from this high surge. So that's another reason why you need an HROD because that HROD provides that reference to ground for such surge conditions. And so you need to also, because like I said, these surge conditions, when you think that it's likely to happen, it's every exposed material in your house, like a solar panel, they can get induced voltage, very high voltage in their chassis. So what you want to do is you just want to also connect a wire to your solar panel, right? They're made of aluminum and you want to connect to the aluminum frame. If you use a rail, like a standard rail, there are lugs you can buy, you just connect one wire to that lug and then you connect it to your HROD, to the same HROD. So that you have, you know, as that thing happens on your solar panel, it just discharges, it just discharge, you just suck them out and just provide them a path to ground. So they wouldn't even need to run through and you wouldn't even need a surge protector. But then, you get a surge protector because you will need to look at some of these things in layers. So in terms of resistance, like we've seen a lot of conversation and a lot of people are kind of worried, like, oh God, how is this different? Dude, it's not that deep. Get your HROD, a lot of the documentation I've read says eight feet. In Nigeria, I don't know how we standardize at six feet because that's what is common, but if you search, if you want, if there's this part of the installation that you really want to worry yourself about, make sure you get an eight feet HROD. And you can get them, you can get them at the locally available earthen shop, but if you go to the major market earthen shop, you can get an eight feet, it can be copper bonded. Don't go for full copper, copper is brittle. So you need something copper bonded. So that means you have a steel core and then you have a copper coating. So if you get steel, copper bonded, eight feet, just go to a part of your house that is best for you because again, water is very resistant. So it's good for you to kind of install it in a place where you know that, okay, here gets a lot of water. A lot of water goes into the ground, like maybe a flower bed or maybe you have a lawn or something, as long as it's not far from your house. You don't want it to be too far. You want it to be very close to your house because you know you need to run it into your house. You need to run wire into your house. You don't want it to be too far from your house. But let's say if you happen to have like, maybe there's a part of your house where it's very close to the main building where you have like maybe you're keeping like a garden or something, you can just put it there because you're gonna be wetting that garden all year round, right? So you kind of just provide natural. In my place, my kitchen is set up in such a way that the kitchen has its own septic tank. But that septic tank is not, because it's just kitchen water. So the septic tank is built with perforated bricks at the base so that the water just leaches away into the soil. In fact, you don't even see an opening. There's no way to open because the idea is that that septic tank would never be full because the water just leaches away into the soil. And so I just installed my air trough very close to that soil and ensuring that there's always, that part of the house always going to be moist. Now, in case you don't have something like that, most places in Nigeria, I believe, I think, should be fine. If you live close to the beach, maybe you live on the island and your house is beachfront and you have a lot of sandy, then maybe you should be worried because, I don't know, I think they are not that resistant. And then maybe you can just get something like bentonite and read up on it and see how you can use bentonite or maybe germs to install. My own experience, I spoke to the person that sells germs in Nigeria, the authorized distributor, and he said, if you no longer ship them because they are very, very expensive. So bentonite is a very good substitute and you can see them available in the market. So you might want to just consider using bentonite. And that's if you live in, like, on a rock or in a very sandy place. I don't know about the northern part of Nigeria. I think sometimes the ground there can get really dry because of the extended dry season. So, yeah, like, I don't know. I can't speak to that, to be honest. I guess maybe for them, they will probably need to get something like bentonite. One thing you can do, if you're worried, if you're worried, let's say you're really worried. Okay, on dry season, the driest time of the month, do a soil resistance test. It's the same test that the guys that do borehole do. It's pretty much they just check the resistance and use the matrix to kind of simulate whether there's a rock under your house or something. I've seen some of their reports and in the report you see the resistance of the soil. It's part of their technical side of their report. So, you could do a soil resistance test of the place you can see how resistant the soil is before you start gapping some money. I think it's about 20,000 Naira to do some of these things. So, yeah, I just want to do that. But if you stay down south in Port Harcourt, you worry, some of those places, Lagos, I mean, you don't have to worry. Just take your etch rod and your eight-feet etch rod, dig a hole, dig a hole like maybe two-feet hole and just hit it inside. Forget about evacuating a hole and putting charcoal. No, the compactness of the earth matters a lot because the earth needs to be in contact with that rod. And you want to do it in a place that maybe preferably hasn't been excavated before so that that compactness compresses against the rod and allows it to have contact. So, you just hit it in and you hit it in and if you have, you can buy like an inspection pit. I think I have something like that and you can just have that in your place and then you should be good to go. Remember, what resistance do you need? You need, the UK say you need 200 ohms for a TT system, which is what we practice in Nigeria. You need 200 ohms. So, I mean, in fact, technically, you need like 1,665 or something like that. That's how much you need ohms in terms of resistance. But they recommend that lower than is fine. And if you look at some of the explanation I was giving, I think you kind of understand. So, if you can get below 100 ohms, then you're good. If you get even 150, it's not the end of the world. Because one thing you want to know is that the resistance of your earth is the resistance up to where your earth bar is on your distribution board. In my case, what I did was when I installed the earth rod, because I knew I was gonna be connecting many things to the earth rod. So, for convenience, I had a buzz bar. So, the earth rod connects to, there is a buzz bar that connects directly to the earth rod. And that allows me to add more things to that earth rod, to connect things to the earth rod. Now, I don't know if this is a standard way of doing it. It kind of makes sense to me. And I think I've seen it one or two places before. If it's not kosher, I'll still check if this is the right way to do something like that. But I can't figure out a way of how do you connect wires to the earth rod directly. What makes sense for me is for you to have some form of a bar, you know, copper bar, very strong bar that I can handle, you know, and I've shared pictures of this bar. And then, you know, my solar panel wiring from the frame of my solar panel connects to that bar. My DSTV satellite dish connects to that bar. Everything connects to that bar. And my DB, the wire from my DB, that's the earth bar of my DB, goes in and connects to that same bar. My inverter board, I put some bus bar at my inverter board because I needed to be connecting things like my SVD earth. I need to find a way to easily connect it to the earth rod. So it was easier for me. So it's more like just having like a, the way you always have an extension, an extension box, in order for you to be able to put money connection. That's what a bus bar does. So I just have that bus bar. And I had that bus bar kind of just connect to the various, you know, to the bus bar. I put it so that it's easy for me to make that connection. And then wire goes from that bus bar to the main ground bus bar outside of the house. And that's how I have my system. I've had NEPA come in, people from the grid, to come and test my installation. And they found that I had 14 homes. And I had 14 homes because, well, I had a different understanding of how things should work. I too was chasing or asked, you know, I need to have like five homes or something like that, which is like way, way below the recommendation. I mean, if you can do it, you can spend a lot of money on it, that's fine. But for some people, you're just going to be burning money, trying to achieve something. And where your effort could be done, you know, put out all that things. Like you can buy an SPD, you can buy an RCBO, you can clean up the wiring of your house. You know, money is opportunity cost. That's my thinking anyway. So if you have something like 50 homes, 80 homes, 70 homes, that's fine. Like it's not the end of the world. It will still happen. Electricity will still be the lowest resistance part in your house. And electricity will flow to it. You just want to make sure that the wire coming from your DB, from the above your DB, you want to make sure that at least 16 mm, please don't listen to people saying 2.14 point something. Remember, you're looking for the path of this resistance. And so if the thinner the wire, the more resistance, so the bigger the wire, the lower the resistance. So you want to get that wire and connect it to the ground bar. And that's what I did. I just got 16 mm for my DB. And I think when they ran the resistance between my DB and my ground rod, it was around 14 homes, I mean, 17 homes, which I feel like, you know, that's good. I mean, it's good. So I decided to just make this small, this small content just to explain what I did and just to explain some of the concept. I hope you understand. I hope you guys find it helpful and let the conversation continue.
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