Connecting the protective conductor with the neutral in the TN-C network

Hello.
I am a very beginner in the subject of electricity, so although there are topics on connecting the protective conductor with the neutral in the TN-C network (I have an old installation, without a protective conductor), I would like to present my situation in detail.
I have a lamp in front of the garage, the cable is routed in the ground, in a conduit. I connected the neutral wire to the protective wire which is connected to the metal housing of the lamp. The connection is in a box in the garage.
Is this connection consistent with what I was referring to, i.e. the connection according to? website https://elektrykadlakazdego.pl/uziemienie/
Will this part of the installation be TN-CS?

If for some reason the phase wire touches the housing, in this system the voltage will pass through the housing, through the protective wire to the point of connection with the neutral wire and, causing a short circuit with the phase wire, will blow the fuse (10A).
If the damage to the neutral wire occurs behind the point of connection of the neutral and protective wires, then if the phase wire in the lamp touches the housing, there will be voltage on the housing and nothing will cut it off.

The connection is correct (as long as you are sure that your network layout is TN-C). From this point on there is a TN-CS system. Except that you do not separate the N wire, but it is then called PEN.

wprost123 wrote:

If for some reason the phase wire touches the housing, in this system the voltage will pass through the housing, through the protective wire to the point of connection with the neutral wire and, causing a short circuit with the phase wire, will blow the fuse (10A).

Yes.

wprost123 wrote:

If the damage to the neutral wire occurs behind the point of connection of the neutral and protective wires, then if the phase wire in the lamp touches the housing, there will be voltage on the housing and nothing will cut it off.

Behind the chapter, no. No N. This would happen if the protective conductor was damaged. And before the separation it`s worse, because voltage will appear immediately after breaking this wire. Even when the phase does not touch the lamp.

Before the chapter you have a PEN cable. After the chapter N and PE separately.

In your drawing, in the upper left corner, after taking into account the description, instead of N, there should be the inscription PEN.

Quote:

And before the separation it`s worse, because voltage will appear immediately after breaking this wire. Even when the phase does not touch the lamp.

Before the chapter - I understand that you are talking about damage to the PEN cable in the garage?

Is there anything that can be improved here for safety? (apart from adding a protective conductor throughout the installation and connecting the RCD)

Added after 1 [minute]:

slawekx wrote:

In your drawing, in the upper left corner, because of the description, there should be the inscription PEN instead of N.

I corrected it, thanks.

Added after 24 [minutes]:

I understand that the damage before the division was related to the damage to the PEN cable in the garage. Then, when the lamp is turned on, there will be voltage on the housing. It will go from phase, through the bulb to neutral and neutral to protective, and nothing will cut off this voltage, because the PEN wire will be damaged, so there will be no short circuit and the fuse will not blow.
So you have to choose which side I want to protect, or... separate the PEN earlier, i.e. at the entrance to the garage? Then it will be safe both in the garage and under the lamp?

michu-michu wrote:

I understand that the damage before the division was related to the damage to the PEN cable in the garage. Then, when the lamp is turned on, there will be voltage on the housing. It will go from phase, through the bulb to neutral and neutral to protective, and nothing will cut off this voltage, because the PEN wire will be damaged, so there will be no short circuit and the fuse will not blow.

Exactly.

wprost123 wrote:

separate PEN earlier, i.e. at the entrance to the garage? Then it will be safe both in the garage and under the lamp?

The current requirement for the cross-section of a PEN conductor is 10mm2. In old installations, it is often of smaller cross-section and more susceptible to damage. The sooner you separate it, the better, theoretically.

PEN doesn`t interrupt itself so willingly.
Break = PEN burnout due to poor connections.
The break in PEN mainly concerns old installations in the TN-C system.

Therefore, the installation should undergo periodic inspections and measurements.
Do you perform periodic inspections?
Have you commissioned an electrician to do this in your installation?

Start with this.
You can`t do it yourself because you don`t have a meter and you can`t do it.

PEN break in the garage - if WLZ 3f is there, the receivers will be damaged as a result of the PEN break.

The part of the installation in question will only power the lighting and one socket (I know that in new installations the lighting and sockets are already divided).
I connect wire-type cables on "plug-in" connectors, something like Wago, the ones that lock themselves when pressed. The package said they could withstand up to 24A. Do you trust them, or do you think classic dice are better?
Do I think it`s right that to reduce the likelihood of the wire burning, I did the right thing by turning it off?
overcurrent 10A? The above-mentioned lamp and, for example, a drill are connected there.

It`s an error. First you theorize that you want to learn, and now you present that it is supposed to be a separate installation. This installation is faulty.

wprost123 wrote:

Is there anything that can be improved here for safety? (apart from adding a protective conductor in the entire installation and connecting the RCD

You can, and even have to. If you divided the PEN cable into N and PE, it would be best to ground the place of division. Even make a ring grounding if you don`t have any foundation grounding. This is some protection in the event of a break in the neutral wire. Otherwise, in my opinion, division without grounding makes no sense. Personally, I recently replaced a lamp with a metal housing in my kitchen. TN-C installation and I didn`t connect any protection because I don`t have anything to do with it. Such zeroing is not protection. My father is an electrician by profession and he always said. There is grounding, i.e. 3 wires or 5 - connect. If not, don`t connect. No zeroing. Neither in lamps nor in sockets

Moderated By Łukasz-O:

3/1/11. Don`t send messages that don`t add anything to the discussion. They are misleading, dangerous or do not solve the user`s problem.
Warning.

Jamesbond664478 wrote:

If you divided the PEN cable into N and PE, it would be best to ground the place of division.

Why the place of division?

Jamesbond664478 wrote:

Otherwise, in my opinion, division without grounding makes no sense.

And why? Don`t think this provides protection? What do you think this grounding accomplishes?

Jamesbond664478 wrote:

TN-C installation and I didn`t connect any protection because I don`t have anything to do with it.

This is a serious mistake. It is class I protection, there must be a protective conductor.

Jamesbond664478 wrote:

Such zeroing is not protection. My father is an electrician by profession and he always said. There is grounding, i.e. 3 wires or 5 - connect. If not, don`t connect. No zeroing. Neither in lamps nor in sockets

And that`s complete nonsense. PENa separation is much more than grounding. The metallic short-circuit loop itself is a very good protection measure.

michu-michu wrote:

Otherwise, in my opinion, division without grounding makes no sense.

And why? Don`t think this provides protection? What do you think this grounding accomplishes?

In my opinion, for example, in the case of zeroing lamps or sockets with a so-called bridge, this is no protection. All it takes is a break in the neutral wire (poor connection, disconnection from somewhere under the connector or terminal or drilling of the wire) and zeroing will not help. The voltage through the device being used is on the housing and the shock is ready. The only way to properly protect yourself is to conduct and perform the installation correctly. That is, running protective conductors from switchboards. PEN division in the switchgear and grounding. An even better division would be at the joint. But that`s just my opinion

Added after 3 [minutes]:

Coming back to the author`s post, the division you made is OK, if you ground it, you have a very good means of protection. Then, in the event of a break in the neutral wire, you will not be at risk of electric shock

Moderated By Łukasz-O:

I suggest you stop giving advice in electrical departments.

Friend Jamesbond664478, fortunately, it`s just your opinion, but don`t propagate it and don`t spread it on the forum.
Laymen read, electricians read and... they are filled with horror.

Jamesbond664478 wrote:

michu-michu wrote:

Otherwise, in my opinion, division without grounding makes no sense.

And why? Don`t think this provides protection? What do you think this grounding accomplishes?

In my opinion, for example, in the case of zeroing lamps or sockets with a so-called bridge, this is no protection.

Uneducated people have such views and are not ashamed to reveal them. Horror, indeed. Take pride in your ignorance.

wprost123 wrote:

Am I right in thinking that to reduce the likelihood of the wire burning, I did the right thing by using a 10A overcurrent breaker?

You`re thinking wrong - a fuse won`t do any good for this purpose.
Author of the topic - do not replace the inspection by adding an additional fuse or RCD.
This is a method to improve security.

Let an electrician do a 5-year inspection - it will help a lot because it will detect faults.
Such an inspection is required by law - people do not do it, because there are no controls and penalties for lack of inspection.

wprost123 wrote:

TN-C networks (I have an old installation, without a protective conductor)

The ban on TN-C reception installations has been in place for a long time.
Old installation - more than 25-30 years old.
Admit it - has such a review ever been done?
I`m convinced never.
Later there was a complaint that the connections had "coaled".

retrofood wrote:

Jamesbond664478 wrote:
michu-michu wrote:
Otherwise, in my opinion, division without grounding makes no sense.

And why? Don`t think this provides protection? What do you think this grounding accomplishes?


In my opinion, for example, in the case of zeroing lamps or sockets with a so-called bridge, this is no protection.

Yes, I think so. And I wouldn`t want anyone to experience electric shock from such installations

retrofood wrote:

Uneducated people have such views and are not ashamed to reveal them. Horror, indeed. Take pride in your ignorance.

If you experienced such things in reality, you would appreciate the correctness of installation and grounding. Let`s take care of our own safety and the safety of others. And not "because that`s how it used to be done or is still being done"

Jamesbond664478 wrote:

retrofood wrote:

Uneducated people have such views and are not ashamed to reveal them. Horror, indeed. Take pride in your ignorance.

If you experienced such things in reality, you would appreciate the correctness of installation and grounding. Let`s take care of our own safety and the safety of others. And not "because that`s how it used to be done or is still being done"

In order to teach someone how to properly perform installations, you must first learn it yourself, and not preach what "you think". And distinguish between zeroing and grounding. Therefore, please stop preaching heresy, this is not the place for such views.

Quote:

Otherwise, in my opinion, division without grounding makes no sense.

Jamesbond664478 wrote:

Yes, I think so.

Then show it on the parameters of the TN system.
Tell us what parameters will change after grounding the split point.
This is a professional forum - everyone will understand it.

Electrics is an exact science - it deals with numerical values of parameters.
Literature works on words - electricity works on numerical values.
I will give my friend the output data for discussion - IPZ on the 0.3Ω connection

retrofood wrote:

In order to teach someone how to properly perform installations, you must first learn it yourself, and not preach what "you think". And distinguish between zeroing and grounding. Therefore, please stop preaching heresies, this is not the place for such views

I happen to be an electrician and I work with a team. Maybe not too long, 4 years, but actively and on an ongoing basis. So I`ve seen and done a bit. Zeroing is performed in installations, but I try to avoid this type of connections if possible

CYRUS2 wrote:

Then show it on the parameters of the TN system.
Tell us what parameters will change after grounding the split point.

I didn`t say that the parameters would change. Will they be better or worse. Grounding the PENa split point is intended to ensure safety in the event of a break in the neutral wire. Regardless of whether the break occurs before or after the split point. Then there will be no voltage on the PE wire - including on the housing. In the author`s case, this is the best solution, because the lamp is in front of the garage. Exposed to weather conditions (snow, rain) and more susceptible to possible punctures on the housing. SAFETY COMES FIRST

Jamesbond664478 wrote:

retrofood wrote:

In order to teach someone how to properly perform installations, you must first learn it yourself, and not preach what "you think". And distinguish between zeroing and grounding. Therefore, please stop preaching heresy, this is not the place for such views

I happen to be an electrician and I work with a team. Maybe not for too long, 4 years, but actively and on an ongoing basis. So I`ve seen and done a bit. Zeroing is performed in installations, but I try to avoid this type of connections if possible

You don`t have to "try to avoid", but perform zeroing where it is necessary and necessary and do not perform zeroing where it is prohibited! .
And learn to distinguish one situation from another.
The "trying" you have shown so far is pure ignorance.

Jamesbond664478 wrote:

I didn`t say that the parameters would change. Will they be better or worse? Grounding the PENa split point is intended to ensure safety in the event of a break in the neutral wire.

So what`s the "miracle" method?
Without parameters?
You wrote without any sense, my friend.

Jamesbond664478 wrote:

I happen to be an electrician and I work with a team. Maybe not too long, 4 years, but actively and on an ongoing basis.
Zeroing is performed in installations, but I try to avoid this type of connections if possible.

Zeroing has been banned for a long time.
My young electrician friend has no choice in principle "I can, but I avoid it."
The method of protection is determined by regulations.

CYRUS2 wrote:

My young electrician friend has no choice in principle "I can, but I avoid it."
The method of protection is determined by regulations.

That`s exactly right! The electrician is obliged to use a protection method that results from the existing situation or - in the case of a new installation - from the power supply network system. And he`s not doing anyone any favors!

So please post here a link or a PDF with an article that would explain in what situations you should not use zeroing when dealing with a TN-C installation.

Quote:

The protective-neutral conductor (PEN) may only be used in permanently installed electrical installations, have insulation appropriate to the nominal voltage of the system and, due to mechanical strength, should have a cross-section of at least 10 mm2 Cu or 16 mm2 Al.

(although it is not a PDF) https://bezel.com.pl/2018/08/01/przewody-ochronne/
This is among other things. However, if we have a situation with the existing installation, we can allow a lower PEN cross-section, corresponding to the standards at the time the installation was performed.

wprost123 wrote:

So please post here a link or a PDF with an article that would explain in what situations you should not use zeroing when dealing with a TN-C installation.

In what cases should they not be used? If the TN-C power supply system is in force in your area, i.e. the power supply supplies 1F/3F and PEN to your connector, it used to be standard to perform zeroing in sockets and devices that had a separate terminal/conductor for N and PE because people only put it in the walls two wires - this is still a very important means of protection in old installations, when we are talking about class I devices.

When not to do it? So you are simply asking when not to connect the protective conductor of the device to the installation - generally NEVER. I see a theoretical case when you have an ungrounded socket and there will always be a class 2 receiver plugged in there - in practice, however, this is a utopia, because you cannot guarantee that no one will plug in a kettle there in a moment, so to sum up - in my opinion, in the mentioned metal lamps - they should be replaced sockets with a pin - you should and perform zeroing - you should.

By the way, I`m too young to remember it, but what was it like in the past? Devices (back then) were grounded locally? My grandfather once told me that, for example, a saw was used to stick pins into the ground, a TN system, but what about the first electric irons? Someone tell this, please

wprost123 wrote:

So please post here a link or a PDF with an article that would explain in what situations you should not use zeroing when dealing with a TN-C installation.

Buddy, in your situation, the best solution will be to ground yourself and perform PEN divisions. This is the safest option due to the location of the lamp

Jamesbond664478 wrote:

wprost123 wrote:

So please post here a link or a PDF with an article that would explain in what situations you should not use zeroing when dealing with a TN-C installation.

Buddy, in your situation, the best solution will be to ground yourself and perform PEN divisions. This is the safest option due to the location of the lamp

I would stop calling the cable PEN, because I don`t think there is a minimum required cross-section, but ok, I`m nitpicking. However, my colleague still hasn`t proven with numbers/drawings what this grounding will bring/deliver to him?

Please forgive me, but if you are challenging the same view as your father - oh, horror, also an electrician - then I suggest you go to SEP together and hand over your qualifications, or humbly verify your knowledge. and there should be a temporary ban on the forum, because you are also read by amateur electricians and young people in the profession. Anyway, have a nice day

The basic mistake is mixing eras.
The old zeroing is not today`s TN-C, although the method of protection against shock remains the same, although the names are different. It is based on a metallic connection of parts accessible to the N point of the network.
Today, the basic difference is the requirement for a minimum PEN cross-section, which was not the case for the neutral conductor, and in order for this system to be used in receiving installations, the PEN (formerly the neutral conductor) was separated into a protective and neutral conductor, creating TN-S/TN-CS.

PBUE required the sockets in the kitchen and bathroom to be reset. The remaining sockets in the apartment did not have a protective contact. It was assumed that the high resistance of the substrate would prevent electric shock even if the insulation of the receiver made in (no longer produced) class 0 or class I protection was damaged.
Today, the type of room does not determine the presence of a socket with a protective contact. Today, all sockets must have such a contact. An exception may be sockets whose construction allows only plugging in a receiver plug with protection class II.
Of course, the PE conductor must be connected to this socket.

And these old rules when they come into contact with today`s standards cause confusion.
In my opinion, great caution is required when our intervention in old installations is limited only to replacing sockets.
First of all, we apply the principle of existing protection, i.e. installing a socket with a protective contact is an interference with the previously applied anti-shock protection. And we will be responsible for the consequences of any possible damage.
It`s not a big deal if the old installation has copper wires. But if it has aluminum conductors, in my opinion it is better and safer to replace the installation than to use sockets with a protective contact. But that`s just my opinion.
And secondly, you must follow the rule that there cannot be sockets with and without a protective contact in the same room.

So caution is required when adapting today`s standards to old two-wire installations.
The corpse does not resuscitate.

kkas12 , thank you, it clarified the topic more for me. :)

In fact, with an aluminum installation, zeroing is the last thing I would think about. However, I see that your statement goes to the other extreme compared to the user theory Jamesbond664478 , which does not use zeroing, because NO, and does not connect the PE cable.

kkas12 wrote:

The basic mistake is mixing eras.
The old zeroing is not today`s TN-C.

Today there is no TN-C in residential buildings.
A TN-C distribution network only means that a PEN cable can be used for protection.
That you can make N+PE from a PEN cable.

What he preaches here Jamesbond664478 it`s pure heresy, nothing more.
Only complete ignorance, ignorance of the rules, standards and everything on which we rely can be its basis. Well, I know they`re calling, but I don`t know where.

My friend does not know that equalizing connections, and therefore the grounding of the neutral wire, have been in force in this country since 1968.
My friend also does not know that it is not about the grounding (in new installations) of the PEN division, but about the grounding of the PE conductor. However, this should be done at the beginning of the installation, not at the end.
My friend also does not know what will happen if the PEN in this case is damaged at the beginning of the installation and this garage earth electrode will try to take over its role.

My friend also does not know that making local equipotential connections is unacceptable if the facility does not have main connections.
And what I propose here is exactly the same.