Preparing & Installing Photovoltaic Panels: Cable Routing, Electrical Work, House Construction

I warmly welcome.
Next week I am going into electrical work on a house under construction. After the last meeting, the investor asked if we could prepare the installation for the photovoltaic panels that are in the plan. A question for you, how to prepare the installation? Where to pull the cable? I have never left cables for photovoltaics. Maybe someone could share the knowledge?

You will need to know:
1. Where the panels will be located.
2. What will be the power (total).
5. Where will the controller be placed

Take a look here: https://sanko.com.pl/

I already know all this from the investor.
1) The panels will be on the roof
2) Power of approx. 5 kW
3) Kontrolere, i.e. the inverter will be next to the main switchboard in the garage.

If it is a 48V installation, it comes out that a current of more than 100A will flow at the peak.
So two veins min. 16 mm2 from the collection point to the location of the inverter.
On the roof, of course, a specialized cable (UV resistant) as in the link ...

And that's all ?
It is enough that I connect 2 x 16 mm2 from the inverter to the place where the solar panels will be located?

any56 wrote:

If it will be a 48V installation

And where is the voltage at 5 kW from?

What will it be inverter, how many strings? Does the client have an eye on a specific set?

matik185 wrote:

I warmly welcome.
A question for you, how to prepare the installation? Where to pull the cable?

Part of AC
To the inverter installation site, 5x4mm2 cable from the main switchboard and LGY 1x16mm2 yellow-green from GSU.

Part of DC
From the place where the inverter is installed to the attic (as close as possible to the top of the roof where the panels will be installed), two solar cables (with reinforced insulation) for each group of panels. (preferably in different colors). If the cable length between the panels and the inverter is significant (exceeds 10m), the same place is LGY 1x16mm2 from GSU.

The roof should also be grounded on the outside of the panel frame (e.g. with 10mm aluminum wire).

It is also good to lead a shielded twisted pair from the main switchboard and multimedia switchboard to the inverter installation site (to the net and communication with the meter).

I repeat the question, where does this voltage come from at 5 kW?

Hello

I think that my friend matik185 has experience with home electrical installations and making one is a piece of cake for him.
The situation puzzles me.

1. The investor probably has little idea about PV, and even if he does, it is not known what he meant. You can guess that 90% of it was on-grid installation.
2. The number of possible solutions is quite large - especially when you do not know the local conditions. FV panels in the plan - it can be even in 10 years, and then the solutions can be completely different.
If I were there, Col. matik185, I would not care too much about it and would do my job, or I would press the investor to be more specific, because the fact that he has an FV in his plans is not enough.

I myself have little experience in this field. Last year, we launched one 4kWp installation and we are in the process of launching 16kWp (currently offgrid). If it goes well, I will start 4-5kWp this year (I also plan ).

kisses
- GIFT-

Wall the arota between RG and the attic, and that's it. The panels will be installed, what will be needed there will be sucked in. Leave space for the inverter in the RG or next to it.

I thought you would get the meaning of my questions.
5 kW
What panels - 100W / 12V? 250W / 24V? Or maybe other? They all work in series in one loop? Count the rest.

opornik7 wrote:

I thought you would get the meaning of my questions.
5 kW
What panels - 100W / 12V? 250W / 24V? Or maybe other? They all work in series in one loop? Count the rest.

Hello Jack. I do not fully understand what you mean?
First of all, I thought to myself (and probably not only me) that my colleague any56 is the addressee of the question - he wrote about 48V.
Secondly, the on-grid solutions known to me work on a much higher voltage, i.e. cell strings connected to 600V. It is also rather obvious to the debaters.
As for the other solutions (batteries, heating water with heaters), we have almost freedom here.

kisses
- GIFT-

kortyleski wrote:

Wall the arota between RG and the attic, and that's it. The panels will be installed, what will be needed there will be sucked in. Leave space for the inverter in the RG or next to it.

I guess I will. He does not want to trick the customer into unnecessary wire costs

Added after 1 [minutes]:

Darom wrote:

Hello

I think that my friend matik185 has experience with home electrical installations and making one is a piece of cake for him.
The situation puzzles me.

1. The investor probably has little idea about PV, and even if he does, it is not known what he meant. You can guess that 90% of it was on-grid installation.
2. The number of possible solutions is quite large - especially when you do not know the local conditions. FV panels in the plan - it can be even in 10 years, and then the solutions can be completely different.
If I were there, Col. matik185, I would not care too much about it and would do my job, or I would press the investor to be more specific, because the fact that he has an FV in his plans is not enough.

I myself have little experience in this field. Last year, we launched one 4kWp installation and we are in the process of launching 16kWp (currently offgrid). If it goes well, I will start 4-5kWp this year (I also plan ).

kisses
- GIFT-

I do feel a little irony in your speech, don't I?
I have no experience with photovoltaics - I will be doing the installation in a house - a new house, so I wanted to prepare something for FW in order to avoid forging and problems during the installation of panels in the future.

Hello my friend matik185

matik185 wrote:

I do feel a little irony in your speech, don't I?

There is not even a "hint" of irony in my speech. Perhaps I exaggerated a bit with this "piece of cake" - I don't really know you. I assume that you are an electrician and know this profession, which does not mean that you are a specialist in everything that is electric. I think that at least 70% of electricians who make home electrical installations have not done (yet) photovoltaic installations and I would not have known about them (not having a detailed design).

And the message from my previous post (# 10) is that you shouldn't do anything by force, especially when
a) you have insufficient knowledge and practice for PV installations
b) they are independent installations - not affecting each other (and this is the case here).
In fact, this "preparation" should be limited to what the corticals wrote and reserved space on the wall (for the inverter) and in the RG.

kisses
- GIFT-

Darom wrote:

b) they are independent installations - not affecting each other (and this is the case here).

I do not entirely agree with this statement. PV installation is related to overvoltage protection, lightning protection and equipotential bonding. The working inverter affects the power balance and SWZ.

Quote:

In fact, this "preparation" should be limited to what the corticals wrote and reserved space on the wall (for the inverter) and in the RG.

Arota to the attic is actually a good solution.
I would advise to connect the media and "ground" from GSU to the place of installation of the inverter.
3f power line directly from the distribution block in front of the RCD.
I have made a lot of PV installations and with these things there is the biggest problem, "before plastering" costs and workload is much lower.

taniam wrote:

The running inverter has an effect on power balance and SWZ .

Could you write something more about it?

taniam wrote:

3f power line directly from the distribution block in front of the RCD.

What about a circuit breaker or switch disconnector - not required?

kasprzyk wrote:

taniam wrote:

The running inverter has an effect on power balance and SWZ .

Could you write something more about it?

Each facility has a specific power allocation from the electric power supply and appropriately selected protections, the PV inverter is a source of additional energy that should be taken into account when selecting the elements of the main current path of the switchgear. Inverters have the ability to regulate the reactive power, this also has to be taken into account.
As for the SWZ, both the IPZ measurements and the overload tests give different results with and without PV.
Granted, with the 5kW 3f discussed here, it does not matter that much - but with higher power or 1f installation, I had to convert the RG several times at the customer's place, because the cables started to "heat up".

Quote:

taniam wrote:

3f power line directly from the distribution block in front of the RCD.

What about a circuit breaker or switch disconnector - not required?

Each wire must be protected with a circuit breaker or a fuse . We connect with a separate line, parallel to the WLZ, behind the main switch.

taniam wrote:

Each facility has a specific power allocation from the electric power supply and appropriately selected protections, the PV inverter is a source of additional energy that should be taken into account when selecting the elements of the main current path of the switchgear.

My question concerned the fragment in bold, i.e. only SWZ

taniam wrote:

As for the SWZ, both the IPZ measurements and the overload tests give different results with and without PV.

What overload tests?
"with and without PV" what does it mean? with the inverter connected and the photovoltaic modules disconnected? when operating at full power or at minimum, at what point is the IPZ measured?

taniam wrote:

Granted, with the 5kW 3f discussed here, it does not matter that much - but with higher power or 1f installation, I had to convert the RG several times at the customer's place, because the cables started to "heat up".

It's not nice, you haven't checked before installing the PV, whether you can safely connect it to the existing installation, only after the fact?

kasprzyk wrote:

What overload tests?
"with and without PV" what does it mean? with the inverter connected and the photovoltaic modules disconnected? when working at full power or at minimum, ...

An example situation:
Installation of the object 1f, protection 25A "C". PV 1f installation with a power of ~ 3kW. Turning on the thermal bath and electric cooker at the same time without PV energy causes the activation of the pre-meter protection. In production from PV ~ 2kW, both devices can work simultaneously.

Quote:

... at which point are the IPZ measured? ...

Regardless of the measuring point, the IPZ is lower when the inverter is running.

Quote:

It's not nice, you haven't checked before installing the PV, whether you can safely connect it to the existing installation, only after the fact?

Bringing the customer's RG to order is not a standard responsibility.
The cable thickness, IPZ, and the quality of earthing are checked.
If these parameters are OK, the inverter can be connected.
If not, a new wire is laid, earthing is made, and the type of protection is changed.
My additional work is checking the switchgear with a thermal imaging camera. It is ideal if the PV production is high at the time of checking. Only the thermography shows what is happening in the switchgear.

I will step on the topic and ask for understanding / writing in Polish! . I am generally at the house building / finishing stage. I will certainly be tempted by photovoltaics one day, but at the moment I just wanted to put conduits or wires in them so that I would not wash anything in the house and it would be easier to install. On the Ikea website, in the calculator, I calculated that I can install 8 links on one PDW roof slope (I do not know what they are, I do not know) and on the other PDW slope, another 8 pcs. That should give 4,000-5,000 Kwh per year in my area. And now, from the attics above the attics (this is my roof layout), I wanted to lead to the garage where there is an electric box with 2 conduits, one for one set of 8 cells, and in the garage there would be all this "control room". The length of the road, attic / garage is about 15m. The question is whether 2 x 25mm conduit is enough and, if necessary, what kind of cable / wire to insert into it with the assumptions I gave. I know that there are special cables for photovoltaics resistant to UV and precipitation, but I am talking about the draft inside the house, so I understand they can be simpler / cheaper (only their end will be on uninsulated attics - with access from the attic). My electrician is unfamiliar with photovoltaics, but he says that when inside, you can use an ordinary cord in rubber insulation 2 x 4mm2 for each set of 8 panels and a 25mm conduit. Is it good or screwed? I was wondering about voltage vs insulation. All in all, I am mainly concerned about the 25mm diameter of the conduit, or is it enough, because if the 4x4mm2 line goes there, despite the numerous bends, it should be able to be stretched and later. Thanks

The larger the diameter inside the conduit, the better, take at least 28mm (inside), together with the remote control. Two such "tubes" for each set of modules. (perhaps also an equalizing line will be required)
When the conduits are laid, you will take care of the cable later.

Added after 7 [minutes]:

taniam wrote:

An example situation:
Installation of the object 1f, protection 25A "C". PV 1f installation with a power of ~ 3kW. Turning on the thermal bath and electric cooker at the same time without PV energy causes the activation of the pre-meter protection. In production from PV ~ 2kW, both devices can work simultaneously.

that how ????? that is, the client looks out the window, makes sure there is sun, turns on these devices and prays that a cloud will not come? :D

taniam wrote:

... at which point are the IPZ measured? ...
Regardless of the measuring point, the IPZ is lower when the inverter is running.

the inverter miraculously improves the parameters of the wires?

kasprzyk wrote:

taniam wrote:

... at which point are the IPZ measured? ...
Regardless of the measuring point, the IPZ is lower when the inverter is running.

the inverter miraculously improves the parameters of the wires?

Hello
It seems to me that my friend is too cheap, he has rushed too much with his conclusions. As the colleague Kasprzyk proved. When it comes to the measurement of IPZ, perhaps a slight increase could be observed. Here a lot depends on the output characteristics of the inverter - I suppose that with a sudden load it will not give too much current, and even disconnect. So his contribution to the "improvement" of the IPZ may be mediocre. I must admit that I did not measure IPZ with simultaneous power supply from FV. Perhaps one of the colleagues will show off the measurements.

kisses
- GIFT-

kasprzyk wrote:

The larger the diameter inside the conduit, the better, take at least 28mm (inside), together with the remote control. Two such "tubes" for each set of modules. (perhaps also an equalizing line will be required)
When the conduits are laid, you will take care of the cable later.
?

Hmm, it's a bit strange what you write vs what I have already learned from another source - a company that deals with editing. Why such an exaggeration with the amount and diameter of the conduits? 4 conduits 32mm each, I would have to make holes for the sewage system . I will have a problem breaking through the concrete garage ceiling and stuffing it somewhere under dry plaster and with passages through the wall. From this solar company they told me that if the inverter is in the garage, then from one set of panels I should take two cables / wires for plus and minus, i.e. with my assumptions 4mm2 x 2 in one conduit and then 25 is enough with a vengeance. It is said that even such typical "solar" thick double insulated single wires are 5.5mm in diameter, so they can easily enter the 25mm conduit (19 on the inside). Fortunately, in places where the conduit is twisted, I will be able to get it even after finishing the attic, so I don't worry about stretching, because these are supposedly and, in addition, they are always flexible / easy to pull.

You will do as you see fit, as long as the conduits will not be bent, arranged with their internal shape - there will be no problem with dragging the target cable later, life often shows otherwise, and a 15m section is quite a lot under the plaster.

I know that, I have been tired of many such delays. But fortunately, out of the 15m in the conduit / wall / ceiling / under plaster, I only have about 5 meters and 4 larger bends, 2 of them are accessible without ripping and on special fasteners that I can pull apart, so I'm not worried about that. The number and diameter of the cables are crucial for me to know what conduit and now I know that 25mm is enough. But thanks for the response.

I have a question about the wiring and earthing of panel frames. I know that DC cables should be run as close to each other as possible in a parallel manner. The frames of the panels should also be earthed or connected to the lightning protection system, depending on whether the distance between the panel and the lightning protection is greater than 0.5m. In my case, the panels are connected to each other with a 10mm2 PE cable with galvanized meshes in half of the panels, one in series with the other. And on the eyelets it gives stainless washers (those that bite into the frame, I do not know the professional name) at the ends, a link with the profile and then with a 16mm2 cable to the box on the roof where I have security. And so I do with three frames on which I have panels. The question is, can DC cables be run in the same conduit with PE conductor? In the PE box, he wants to connect them on a common strip and then run the chimney with the DC cables to the basement where the invert and PE wire of the panels to the common earthing strip will be connected. I mean disruption and security.