Options for Adding Grounding to Two-Core Aluminum Electrical System

Hello,
I have a two-core aluminum electrical installation without grounding at home,
and I am just thinking about putting grounding in electrical sockets.

I have already talked to electricians and they have different opinions:
-One says that you need to replace the entire installation with a new copper with grounding, it takes about PLN 70 from the point;
- the second one says that "zeroing" is enough, that is, using the existing installation and the neutral wire as grounding, the cost is about PLN 200 for such modernization.

Both electricians also said that approval from the electrical plant was unnecessary.
I haven't called any further, I prefer to find out how it should be done properly.
I am also asking for information how much something like this could cost.

If any additional information is needed, I will try to provide it as far as possible.

Greetings,
Peter

The second electrician is somewhat right, because it is actually enough to make a bridge between the working zero and the protective zero. Nevertheless, it is a rather temporary solution. It would be best to supplement the installation with an additional protective zero (add one wire) and install a residual current circuit breaker in front of the fuses, and then you can be sure that the protective zero is an additional protection. A power plant with existing installations actually has nothing to do with it.

And is this bridge between working zero and protective zero safe? I have heard opinions that it is dangerous.

Will adding one more wire do the trick? No need to re-install?

How much would it cost to re-install a copper earthed installation?

Hello. I would start with what kind of TN or TT network it is?

Kaczmarczyk wrote:

The second electrician is somewhat right, because it is actually enough to make a bridge between the working zero and the protective zero. Nevertheless, it is a rather temporary solution.

If TT is a bridge rather not really, if TN then why ad hoc? I am asking my colleague Kaczmarczyk for an explanation.

theoretically, grounding was not needed, so I wanted to verify whether grounding is needed.
The earthing, i.e. the protective conductor, will cause the protection to operate when the voltage appears on the external elements (in 3-wire installations the residual current device, in 2-wire installations of the overcurrent circuit breaker).
So just by ironing with an iron you will not drop it suddenly: ))

In an apartment with a built-in aluminum installation, the load on the installation is two times lower than in a copper installation with the same cross-section. Due to the fact that aluminum has twice lower conductivity than copper, you have to answer whether to replace the installation or not. The protective conductor must be present in the sockets where they work devices with first class insulation, e.g. computers, washing machines, refrigerators, microwave ovens, gas cookers with an electric oven and all devices with factory-built plugs adapted to work with a reset pin. devices immediately in a two-wire network with a bridge on the protection pin, the overcurrent switch will be activated if it is well selected within about 0.3 sec. If it is a 3-wire cable with a built-in differential, the differential will work when dangerous voltage appears on the housing with potential above 50V and a current of about 30mA during 0.02 sec.

Honestly, I'm a total layman when it comes to electricity
I didn't really understand some of the statements so I read a bit about electrical installations.

ELECTRICAL THEORY
I understand that there are the following types of electrical installations:
- 2-core installation (TN-C) consisting of an L (current) and "zero" PEN conductor (neutral and protective conductor in one),
- 2-core installation (TN-S) consisting of an L (current) conductor, a "neutral" N conductor (neutral conductor) and an additional PE protective conductor (apart from the electric circuit, e.g. a conductor connected to a radiator or an aluminum water supply network)
- 3-wire (TT) installation consisting of an L (current) wire, a "neutral" N wire and a protective PE wire.

In addition, the above installations can be made of wires:
- aluminum (cheaper, worse quality, older type),
-copper (more expensive, better quality, newer type).

Additionally in the TN-C installation, as an alternative to the lack of a third core, " the bridge between working zero and protective zero "- I understand such a bridge as making a branch of the" zero "PEN wire and connecting one end as N and the other end to the pin as PE. Such a branch should be made before each electrical outlet to which devices with the first insulation class will be connected.

In each electrical installation, you can also use the so-called residual current device (RCD) , it switches off the voltage in the electric circuit when it notices that there is "dangerous voltage" in the network, ie when there is a short circuit, or the device is broken.

Ok, I have probably established the theory I need, now I can write more honestly:

CURRENT STATE AT MY HOME
In my house, there is probably a TN-C installation with aluminum conductors without bridges or without a residual current device.

CONCLUSIONS FOR THE MODERNIZATION OF INSTALLATION AT MY HOME
APPLICATION 1
I have two variants:
- 2-core installation + residual current device + bridge between the operating zero and protective neutral -> the circuit breaker works for approx. 0.03 sec.
- 3-wire installation + residual current device -> the circuit breaker works for approx. 0.02 sec.

APPLICATION 2
In my case, it is not profitable to replace the installation with a 3-wire one.

APPLICATION 3
And since a protective conductor (i.e. grounding) is needed for devices with the first insulation class, I should use a bridge between the working zero and the protective zero. Additionally, I need to install a residual current device.
But I don't know where to install the RCD and how many should there be, should it be in front of each electrical socket or at the fuse box?

I guess that's it :|

If I made a mistake, please correct me
It is very important to me because before I call the electrician, I want to know what he is doing and whether the installation will be done correctly.

Greetings,
Peter

Totally bad conclusions.
You haven't read anything in the forum, sad but true.

Thank you for correcting me, the fact I mixed it up a bit and misunderstood some of the things I was reading about.

I have got some questions:
1) What are SWZ measurements?
2) If the protective conductor is not ground, does this bridge give anything? How does the bridge improve safety? I thought that the pin in the socket was supposed to act as a ground.
3) I do not want to put a new installation now because I simply cannot afford it now, the bridge on the TN-C looks the best now, but I do not know if I can use it ... electrical network or renovation, the entire installation must be replaced with a 3-wire one and no bridges must be made. Is this law true and would it apply to me? I just want to improve the safety of sockets, it is not strictly a renovation or a major modernization.

As mentioned above, in a two-wire installation, you only put bridges in the sockets, but first connect the PEN wire to the socket pin and then connect the same wire from the pin to the socket screw and it appears as a neutral N wire. L1 phase wire should be in the socket connected to the left side of the socket. There is no technical possibility to connect the differential to a two-wire installation. From the integrated PEN connector you lead out 2 PE and N conductors. this is how the PE conductor is mounted on the pins and the L1 phase comes from under the differential to the left side of the terminal in the socket and the N also comes out from under the differential to the terminal in the socket on the right side. Your mind requires a bit of refinement. You can see that you are quick to learn and learn quickly.

An expensive solution, but possible to use, are sockets with a built-in residual current switch as in the link:
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piotr7 wrote:

3) I don't want to put a new installation now because I just can't afford it now, the TN-C bridge looks the best for me now, but I don't know if I can use it ...

We still don't know what your network layout is, just because TN-C suits you best (due to costs) does not mean that it is the case.

Thank you very much for your help, I learned a lot of interesting information, now I know what the electrical wiring diagrams in my house look like and how it should look according to the standards. For now, I will use bridges in the sockets, and over time, when I can afford it, I will replace the entire installation with a three-wire one.
It is important that I already know what is what and I know at least briefly the theory :)

@ Łukasz-O: I have TN-C, I checked and turned on the sockets.

@ bourn1984: if I could afford such wonders, I would rather replace the installation with a 3-wire one than buy it for each socket, it would be cheaper.

@ Kierbedz4: It's true that I learn fast I would even like to install these bridges myself, because thanks to you I know how to do it, but I will call an electrician because the cables in the sockets are old and in a deplorable condition and to be honest I am a little afraid to install these bridges myself because I may be electrocuted or broken a vein and there will be more trouble :)

Once again, thank you very much for all your help