Its 2025 and you have been mulling over solar, you want to do it but you have been a little concerned as its messing with electricity well stop mulling over things and lets get started.
Stepping into solar power is a project that most people can do, and its a bug you can catch and you will soon be wanting more. But here is how you can step into solar.
We have smaller projects which will wet your taste, but this project will allow you to make something more useful from your solar.
just buy a AIO and wire these in, they are very simple. just run a earth cable and plug socket and plug your solar into the solar ports, the mains output and turn it on. Yes it is that simple!
Lets look at ATS or using a off grid power solution within the home. (that is on the grid)
Firstly there are many inverters that have a earth neutral bond, ( earth and negative connected) if you connect the input AC with your power output, then you will find it will trip the breaker. DO not connect the mains grid earth. There is more on this and safety notes below where you may want to add sockets into the home and have “dual power” options that is two stand alone power sources.
MAKE SOLAR WORK FOR YOU.
Having power from solar is great as its “free energy”, okay you had to pay for the hardware and now its time to make it pay you back. I hear a lot about running extension cables into the home form the solar shed to plug in the TV, fridge and washing machine, but we shouldn’t do that.
If you have enough inverter power, you should consider an ATS for the full home, This is dangerous and a little beyond the scope of this article. as you may be dealing with grid mains power that you cannot turn off. ( safe isolation).
But what you can do is break down the circuits in your home.
ATS CIRCUITS – Solar power part of the home.
Image provided by – Walker Electrical Ltd
As you can see the image above is a fuse box or consumer unit or distribution board. Its a bit out dated.
But all units are marked with what they are for (labels top) the breakers (fuses) below run a circuit.
We can see B and a number above the switch, for example Shower B 40, and lights High level B 6 This B refers to the current break – B40 is 40 amp trip. B6 is a 6 amp trip.
Lets look at the lights! 6 amps is 1.38kw AC. so with around a 1 kw inverter you could run a lighting circuit. in reality you would not have 6 amps running on a lighting circuit. In reality you may run around 0.45 amps due to new lighting and those energy efficient light bulbs. but before you jump the gun, your power and start up power can vary. ( start up power also called surge).
Lets move our lighting circuit off grid.
To move your house lights off grid you need to isolate the circuit, there can be metal lights that are attached to earth/ground and you should maintain this.
SAFETY NOTE:
In a UK electrical system, if you have a metal light earthed and running from an off-grid inverter, and another metal object earthed from the grid, there could be a potential difference between the two. This is because the off-grid inverter and the grid have separate earth points, and these points may not be at the same potential. The potential difference could be significant, and in the event of a fault, it could lead to a dangerous electric shock.
To avoid this, it is important to ensure that all earth points are bonded together. This means that they are connected by a conductor that is capable of carrying a fault current. This will ensure that there is no potential difference between the two metal objects, even in the event of a fault.
In this context, “potential” refers to electrical potential difference, also known as voltage. It’s the difference in electrical potential energy between two points in an electrical circuit.
If these two potentials are different, there’s a voltage between the two metal objects. If you were to touch both objects simultaneously, your body could provide a path for current to flow, resulting in an electric shock.
To move the circuit off grid you need to remove the wiring from the fuse box, turn it off, check it is off.
The following will vary depending on how your home is wired and access to the wires.
We need to trace the lighting wire, and cut the wire so that we can fit the wires from the fuse box to the “Back up” input of the ATS.
the light circuit side of the cut wire needs to be wired to the output side of the ATS, and the inverter is wired to grid input of the ATS.
You will need to check the ATS earth bond across the switch, and may have to add a wire bridge to keep the earth bond. –
Change the ATS to back up so that your grid supply is powering the circuit. Turn off ALL breakers.
Turn on the main switch and then the lighting breaker that we just worked on.
Check the earth and negative potential at the ATS it should read zero.
Turn on the inverter., if your power trips, this is due to the bond which the inverter has. You will need to disable the inverters bond. – contact your manufacture for how to do this or look at the manual.
If all goes well, you can change the ATS to grid, which is your inverter. Now you can turn on a light.
NOTE: if you have zero exposure to metal conductors within the lights and anything else you do not need to bridge between the earths. this can be a big problem for most inverters as they tend to have the ground/earth negative bond (TNC/ TT). the problem (safety) occurs where the RCD would see a leak between the earth and negative which in home power is a fault condition. The other side of the problem is that inverters can be 230v and the grid 243v There is then a 13v potential between the grid power, and the earth path of the inverter so in effect you introduce the path for electrical shock by having a earth bond.
Stand Alone Wiring (in home installation):
In a home where you can run a cable you could run an off grid system by using a stand alone system.
What you would do is run the wiring for the house, to sockets, lets say green sockets which are available. The wire maybe enclosed in conduit and you would run the cable in the floor space or loft space to the sockets.
This is probably one of the more simple installations provided that you can gain access under floor to run cables and you have wires in trunking (conduit) on the wall surface. Aside from the small ceiling holes and socket mount, the system can be removed easily.
A suitable earth which is NOT bonded to the homes electrical system or pipes should be installed and the connected earth wires within the stand alone system should be installed correctly.
What you would install is your inverter output to a consumer unit and install breakers and RCD units as if you were to be making a fresh domestic installation (TN-S)
The key parts here is that your inverter will provide X amount of power and therefore the fuse and breakers should be limited to the inverter power as a protection system. Most of the good inverters will have a breaker built in, but you should consider what you are doing and what you are protecting.
If you want to look up how to wire this, look at TNC or TT wiring. You could wire earth and ground together at the sockets (TNC). However past the source the installation can be TN-C-S but there is variations due to the type of inverter and connections on the input. Here is a quick summary:
A TN-C earthing system is similar to a TN-S system, but in this case the earth conductor (C) is also used as the neutral conductor. This means that the earth conductor is connected to both the neutral point of the electrical supply and to a metallic structure that is buried in the ground. TN-C systems are typically used in smaller installations, such as in single-phase residential dwellings. ( from the inverter)
A TN-C-S earthing system is a combination of the TN-C and TN-S systems. In this case, the earth conductor (C) is used as the neutral conductor, and there is also a separate earth conductor (S) that is connected to a metallic structure buried in the ground. TN-C-S systems are often used in larger installations, such as in multi-phase commercial or industrial buildings.
An IT (isolated neutral) earthing system is a type of earthing system that is used in systems with a high voltage level (greater than 1 kV). In an IT system, the neutral conductor is not connected to the earth or any other metallic structure. Instead, the neutral conductor is isolated from the earth, and the electrical installation is connected to both the live conductor (T) and the neutral conductor (N). IT systems are typically used in power generation and transmission systems, as well as in some industrial applications.
TNS earthing systems are generally less expensive to install and maintain than other types of earthing systems, such as IT systems. There are several reasons why TNS earthing systems may be less expensive to install and maintain.
- Simplicity: TNS earthing systems are relatively simple and straightforward, with fewer components and a more straightforward installation process. This can make them less expensive to install and maintain than more complex systems.
- Compatibility: TNS earthing systems are compatible with a wide range of electrical devices and appliances, including those with a neutral conductor. This means that they can be used in a variety of applications without the need for specialized equipment or materials.
- Materials: TNS earthing systems typically use inexpensive materials, such as copper or aluminium conductors and metallic structures (such as metal rods or water pipes) for the earth connection. This can make them less expensive to install and maintain than systems that use more expensive materials.
- Labour: TNS earthing systems are relatively easy to install and maintain, which can result in lower labour costs compared to other types of earthing systems.
It is important to note that the cost of installing and maintaining an earthing system will depend on a variety of factors, including the size and complexity of the electrical installation, the materials used, and the labor required. TNS earthing systems may be less expensive to install and maintain than other types of earthing systems in some cases, but this will depend on the specific circumstances of each installation.
Read up more ( new tab)
IMPORTANT NOTE:
Residual current devices (RCDs) may be required for TN-earthed systems, and the neutral and protective conductors must be separated upstream of the RCD for TN-C-S systems. This separation is typically done at the service entrance (grid supply).
Where the inverter is connected to grid power (AC input) The problem is caused where the RCD is downstream of the TT at the inverter leading to a fault condition on the second supply side from the primary.
In such installations the inverter charger will not provide power on its output when grid charging.
ALL installations should be checked for potential between both systems.
NOT COMPLICATED
While that may seem complicated and not really a step for a beginner, it does sound a little more complicated than it is A stand alone wiring solution within the home will be just the same as you have; the issue which seems to be complex is the bonds when the grid and inverter are together at any point.
Live to live faults (420+ volts) can occur where the earth becomes a floating center tap and we can also have tripping issues. When you understand why or how, then you can avoid problems from occurring. Oddly stand alone without any grid is a straight forward installation and why we have to isolate the two systems.
Before venturing into home power and avoiding bridge and bonds you should carry out a stand alone installation separate from any grid.
No responses yet