Connecting RB Switchgear for Construction: TN-C System, PEN to PE/N Separation, 15kV Experience

Hello,

I need to connect the RB switchgear for construction purposes.

When it comes to electrical qualifications, of course I have them (up to 15kV), but I have never worked with this type of installations so I would like to make sure that what I do is correct.

I attach the connection conditions below:

As you can see, the network is in the TN-C system, and the contents of the ZK box look like this:

On the right there is a countdown protection, and in the box on the left, if I understand correctly, I have to lead with this blue conduit my cable from the RB switchgear and plug in the terminals.

In the RB switchgear, of course, 3-phase differential protection and overcurrent protection. In addition, the division of PEN into PE and N through a driven spike into the ground.

What cable do you supply to this RB

I don't have a cable yet, I'm going to RB move about 5m from ZT. I have read that the cable should be 10mm? for continuous loads, but does it make sense to RB? In the construction of foundations, there will be practically no electricity used, glue is foreseen for masonry, so as much as a mixer or brick saw, the rest is the treatment of rafters, etc. Concrete imported in concrete mixers.
That's why I'm thinking about the 4mm? line.

ADI-mistrzu wrote:

I don't have a cable yet, I'm going to RB move about 5m from ZT. I have read that the cable should be 10mm? for continuous loads, but does it make sense to RB? (...).

You run the power supply from ZK to RB in such a system as the power supply network, i.e. TN-C.
This determines the minimum PEN cross-section - 10mm? Cu or 16mm? Al.
If the cable, then of course in pressed sleeves.
It is hard to deduce from the photo, but the strip supports 25mm?. But this must be checked.

ADI-mistrzu wrote:

That's why I'm thinking about the 4mm? line

You cannot use this cross-section in the TN-C system.

ADI-mistrzu wrote:

In the construction of foundations, there will be practically no electricity used, glue is foreseen for masonry, so as much as a mixer or brick saw, the rest is the treatment of rafters, etc. Concrete imported in concrete mixers.

Looking at this from a load point, you probably don't need such a large cross-section as 10mm2 Cu to power your home, so why overpay?

ADI-mistrzu wrote:

That's why I'm thinking about the 4mm? line

The rope is not even, you already know that 4mm2 falls off in TN-C and besides, if the price does not come out as you will give such a cable as it should

Yes, the ends of the wires will be pressed, I just need to borrow a crimper because mine supports up to 6mm, come now I wonder if I would give a normal solid wire, I will not have to run after my friends during the holiday season ...
So to sum up, I lead a 4x10mm? (copper) wire to RB, I split the PEN into N and PE and I connect the splitting point to an additional grounding spigot that I will probably stick right next to RB'tki.

And after equipping TL, I can't tell if the network is TNC or TT.
I recommend you buy a cable like in the building design. At the next stage, you will only unplug the RB and insert the cable into the switchboard.
And try not to write about the cable, because you can't lay the cable in the ground.

@polaklbn , I understand as a wire a single wire, part of a cable. Like in foreign literature, "wire" is a single wire in "cable".
As for the final cable that will be under the building, in my opinion a bit hard, I have the building on the foundation slab. In this case, I have to move RB away from the workplace anyway until they finish work, and then dig the wire.

Most likely it will be that I lead a second cable to the building, I will need a total of 15m, the building is moved away from the fence 10m and the target switchgear will be in the garage, so I don't know if for a few zlotys (compared to other costs) it makes sense actually save on this cable.

By the way, I bought a 10mm? wire once.

polaklbn wrote:

And after equipping TL, I can't tell if the network is TNC or TT.

After all, it is determined by the connection conditions.

ADI-mistrzu wrote:

I understand as a wire a single wire, part of a cable.

Meanwhile....

ADI-mistrzu wrote:

I lead a 4x10mm? cable

ADI-mistrzu wrote:

and then dig the wire

ADI-mistrzu wrote:

I will lead a second cable to the building

It's a cable to be a cable, how many fronts it must have because four is not a cable yet.

ADI-mistrzu wrote:

By the way, I bought a 10mm? wire once.

How to understand

Buddy, there are wires, cables and wires. You can't bury the cord in the ground anymore.
If you bought YKY 4x10mm then you bought a cable.

Geez ... I caught this cable myself ...
Yes, a YKY 4x10mm ^ 2 cable is already installed, in total RB is 5m away from the meter box.

I still have a question for you, I have to fill out the contractor's statement which is very confused at PGE.
The statement includes:
"Reports on measurements of insulation resistance, effectiveness of electric shock protection
and the efficiency of lightning protection with positive results and the wiring diagram *
I left the recipient. I used additional protection against electric shocks in the electrical installation
made through ............................................................... "
Where * means delete as appropriate.

The letter is probably general for installation in a finished building as well as in a construction switchboard.
Insofar as it is logical to take measurements of insulation resistance and electric shock protection, lightning protection and diagram are not likely to apply to RB anymore?
I tried to find a recipe specifying what to do, but for the most part it is ZE.
The conditions indicate that the installation should be carried out safely and by a person with electrical qualifications.

Hello.
Not quite with this logic, mate.
* Delete where not applicable is very adequate to the situation, because you cannot measure the effectiveness of electric shock protection without having the voltage specified for the installation.
You wrote about the "lightning" installation yourself, but the diagram applies

The further into the forest the darker ...

Below is what the writing looks like:

So it remains only to measure the insulation and its scheme, come on, I can sketch it later if necessary, because there is an annotation that they were left with the recipient, i.e. with me.

It is more interesting with the "Affiliated entity statement", namely:
" ... were taken back by a person authorized to
performing independent functions in construction to the required extent, and acceptance has been
confirmed by acceptance protocol without reservations (positive acceptance protocol) "
I can forgive myself the acceptance protocol, but are you suddenly not required any building permits? I understand the building installation, but for temporary installation?
Theoretically, construction has not yet begun, there is no statement yet to be made about it, so by law it is rather just a piece of land.

The above is already asking more out of curiosity for the future because I will try to submit a letter with only electrical permissions.