How to ground a photovoltaic installation - TN-C installation

Edek45 wrote:

For this there is a forum to ask, and your answer to your colleague's question adds nothing to the discussion.

On the other hand, your answer adds a lot to the discussion.
For a person who knows how to read, the answer to the question posed has already been given.

ghajduk wrote:

For the one who knows how to read, the answer to the question posed has already been given.

So why did you answer your friend's question?

Contrary to what you are doing now, I have suggested the best solution for him.

ghajduk wrote:

Contrary to what you are doing now, I have suggested the best solution for him.

It should at least thank you or press a plus for a valuable answer.

I do not count on it, and I advise you to stop beating foam and clutter the thread.
It is because of the practice that you presently present that it is impossible to read most of the content on forums on the Internet.

Using existing grounding is possible but not recommended. If you want to use it, you need to connect as close to the ground as possible and certainly to the hoop nowhere higher.

The distance between grounding and the planned GSU for PV may be decisive.

1) If the grounding of the PEN distribution point in the house is ok, nothing prevents it from being used for the purposes of PV protection equipment.
2) If the PEN grounding does not meet the standards (e.g. it is in a bad technical condition, or the required minimum resistance is not met), it should be repaired and also used for the needs of PV protective equipment.
3) It is best not to connect the earthing of the structure to the panel and the panels with the GSU (PEN chapter point in the building). The most reasonable solution is to make an independent lightning protection earth electrode, bringing the drain wire (steel, aluminum wire, 8mm diameter) to the facade in order to limit the flow of potential lightning current to the installation in the building.

GENERAL NOTE:
It must be remembered that currently used solutions in the field of lightning protection are largely based on the calculus of probability, therefore, especially in this matter, it is worth using common sense. No solution will give us 100% certainty of protection against overvoltage caused by atmospheric charging. With a direct discharge into the house / PV on the roof, often there will be nothing to collect from the panels / inverter, but also from most el. at home, because the protectors will "evaporate". The main task of the lightning protection system is to protect the life and health of people in the building.

ghajduk wrote:

dakius,
If you cannot read with understanding, you do not have the appropriate knowledge, and at the same time you are a very demanding person, I suggest:
- find a decent designer or preferably an expert in the field of electrical installations and networks,
- commission him to develop a design for the installation with earthing,
- on the basis of the above, look for a company that will do it in accordance with the design.

This is what I do not understand ... dog entries on the kennel, or rather something like an aggressive grenade, and the moderators do not react. He falls into infamy Elektroda oh he falls

MichałS wrote:

This is what I do not understand ... dog entries on the kennel, or rather something like an aggressive grenade, and the moderators do not react. He falls into infamy Elektroda oh he falls

And I will tell you that this is not a stupid idea, companies that currently deal with PV assembly often have no idea about electrical engineering as such, not to mention lightning protection. Spending a few zlotys on such a mini-project, preceded by an earlier audit in the place where the PV installation will be installed, is a good idea.
You give such a mini project to the inquiry, everyone knows what to do, if they do it in accordance with the guidelines, you can be sure that the installation will be properly done.

MichałS wrote:

Using existing grounding is possible but not recommended. If you want to use it, you need to connect as close to the ground as possible and certainly to the hoop nowhere higher.

The distance between grounding and the planned GSU for PV may be decisive.

Michael ground is one year old and the value on the probe has been measured and is about 8 Ohm less than 10 per 100%.

The inverter and the rest of the equipment will be built around 2-3 meters from the existing hoop inserted into the basement.
That is why I am asking if this grounding can be used.
I would install the module + structure with the earthing conductor on the facade of the building to the second Bednarek led from the same probe.
That is why I want to know whether to do so in my case or to do so in a completely separate earth electrode. Because opinions on the Internet are divided and, for example, in the links that my colleagues put up above, it also writes that you do not need to and it is important that limiters on the DC and AC sides are present.
So that's where I wanted constructive advice.

Michał GSU connecting the outdoor inverter. Flow The cord to the hoop from the PEN point section would be about 2m from the cordage in the basement.

Unfortunately, I have switchgears in my house on the mezzanine, so to get anywhere with the wires, a bit of the floor can be forged

dakius wrote:

I would install the module + structure with the earthing conductor on the facade of the building to the second Bednarek led from the same probe.

In theory, separate earthing will somewhat reduce the risk of the discharge potential transferring to the building.
On the expensive side, if you had a lightning conductor, you have a common earth electrode for it and the PEN distribution.
Do the same probe, but a separate hoop.

dakius wrote:

That is why I want to know whether to do so in my case or to do so in a completely separate earth electrode. Because opinions on the Internet are divided and, for example, in the links that my colleagues put up above, it also writes that you do not need to and it is important that limiters on the DC and AC sides are present. So that's where I wanted constructive advice.

This is more about protection from overvoltage that is transferred to the installation through low-current cables.
And in the case of earthing the panel structure, it is about direct discharge of the lightning current to the ground.

Hello,

Following this thread regarding PV in the TNC installation, I did not find an answer to one question. Namely, assuming that the DC side of the installation will be made in accordance with the figure from post # 6 (DC protectors and the inverter housing connected to the GSU), whether the AC side of the inverter connected to the TNC network (L1, L2, L3, PEN) should be mounted with a surge arrester ? Does (looks at) ZE (Tauron) require this when reporting an installation? If required, which arrester is better to put on - one dedicated to the TNC (unfortunately it costs not little), can you use the grounding you have made and connect the PE terminal of a typical arrestor (B + C) to the GSU and the PEN conductor at the output of the inverter to the N connector ( here I do not know if I will not do more damage to the receiving installation in the event of a discharge by such a connection than if I did not put a protector on the AC side at all)?

comer3, did you find the answer to your question?

Solutions such as connecting PEN with additional PE through a protector are not practiced. If possible, it is best to install the installation to the 5-wired version.

When is it better to leave tn-c to the inverter itself than to do tn-cs in front of the inverter? Ground the split point to the additional PV earth electrode. Assuming there is a minimum of 4x10mm2.
Then we have normal TN-s protectors. I was also looking for tn-c but dehn protectors and both have a pen.

Hi,

Vulture30 - I have not found an answer to the question I asked above .. All in all, it is no longer relevant because I use TN-CS for the inverter and I give a TN-CS protector on the AC side.

The structure of the panels on the roof without lightning rod and on the roof with lightning rod and separation spacing should be connected with each other by equalizing connections. Then it should be connected to the grounded GSU / GSW. It is not a mistake to conduct this grounding inside the building, as someone wrote earlier, because whether the lightning current flows through it depends on many other factors. This wire should be kept at a distance from others.
If there is a lightning rod on the roof and the gaps are not kept, then apart from the above connection to the GSU, the structure must be additionally connected to the lightning rod. The panels, of course, in the LPZ0B zone.
As for PE, there is no need for PE on the roof and there is no such conductor. :)

Added after 6 [minutes]:

comer3 wrote:

Hello,

Following this thread regarding PV in the TNC installation, I did not find an answer to one question. Namely, assuming that the DC side of the installation will be made in accordance with the figure from post # 6 (DC protectors and the inverter housing connected to the GSU), whether the AC side of the inverter connected to the TNC network (L1, L2, L3, PEN) should be mounted with a surge arrester ? Does (looks at) ZE (Tauron) require this when reporting an installation? If required, which arrester is better to put on - one dedicated to the TNC (unfortunately it costs not little), can you use the grounding you have made and connect the PE terminal of a typical arrestor (B + C) to the GSU and the PEN conductor at the output of the inverter to the N connector ( here I do not know if I will not do more damage to the receiving installation in the event of a discharge by such a connection than if I did not put a protector on the AC side at all)?

Such a protector is available only if the distance along the cable to the T2 protector of the home installation exceeds 10m. If you do not have this protector, do it there first, not at the inverter. It should be the same as the network topology. That is, four-pole 3 + 1 to TT, any four-pole to TN-CS and any three or (if there is one) four-pole to TN-C.
The typical B + C earpieces are a scam. At 90%, you need T2 (old C) and connect it to ground and / or PE.
My installation has been> 5 years without any SPD except the deceived Moeller "B + C" in the main switchboard. Soon I will change to new ones.

ghajduk wrote:

In theory, separate earthing will somewhat reduce the risk of the discharge potential transferring to the building.

In fact, this is the greatest heresy that can be written publicly.

Hi,
So, in addition to the above colleague's post, I will only add that if the PV is at a distance of more than 10 from the switchgear, then additional protectors at the panels are provided.
greetings

This has already been described above by the ghajduk; "Photovoltaic installation without lightning protection
If, during the appropriate analysis of the risk of lightning damage, according to the PN-EN 62305-2 standard, we receive information that the risk of this type of lightning discharges to a tolerable or lesser degree, we adjust our procedure to the absence of lightning protection. In this situation, the supporting structure of the PV module should be connected to the main rail of the potential equalization in the building with a direct equalizing conductor. "