RCD in two-wire: to put or not to put?

))) what the hell

with such a touch, an RCD can !! do not work both in TN-C and in TN-C-S and even in TN-S)))) or it may work depending on the transition resistance of the contact of the human body with the "ground"))

ps I installed RCDs at home on the TN-C-S system and the local PEN did the PEN separation directly in the floor shield, and not once did the RCDs fail for a year.

You cannot separate the PEN conductor in the floor shield! When the zero breaks or burns off in the ASU or somewhere below the riser, in your apartment between the PE conductor and any grounded object, such as a battery, a high potential difference appears. Well, and then making changes to the floor shield, you arbitrarily made a change to the building’s electrical wiring made according to the approved project and not yours. And you had what right? In the event of any damage or threat to human life, you will be held administratively and criminally liable.In any emergency you will be made extreme.

As for the operation of the RCD when touching the phase and zero, then it’s over there is an option that it will work. But in the article I described the most serious scenario, which is not so incredible.

sorry if offended, did not want to ..

not me, but a local electrician made changes in the floor shield, with the words I do it everywhere))

At the expense of burning off zero, vkurse ..., it will be necessary to deliver some sort of protection ...

but the situation with touching the phase and zero, you described as the arguments of people who are against the installation of RCDs, to which I said that such a situation can occur regardless of the type of grounding))

What protection? By altering the power circuit of the apartment in the floor shield, you endanger yourself and your loved ones in real danger, since the simple physical separation of the PEN conductor in the shield is very dangerous! In the place of separation, there must necessarily be re-grounding, which can be done and brought only to the ASU. And if what happens, then where will you look for your smart and skillful electrician? Even if you find it, he will be the first to say in court that you did it yourself. That he is a fool in prison? In your situation, you need to return to the TN-C system. If you have redone the wiring in the apartment, just do not connect the third wire to anything from two sides. Wait for the entire riser to upgrade, then plug in and live with the TN-C-S.

Well, the simplest protection can be a minimum voltage relay at the entrance to the apartment, which will turn off both phase and zero when the voltage decreases ...

as for re-grounding at the point of separation of the PEN conductor into PE and N, where does this information come from ?? regulatory document ?? if it `s not a secret))

This document is called Electrical Installation Rules. According to the PUE, you need to do TN-C-S and re-grounding.

PUE-7 p. 1.7.61: "When using the TN system, it is recommended to re-ground PE- and PEN-conductors at the input to the electrical installations of buildings, as well as in other accessible places."

To do this, the "main grounding bus" is made in the ASU and a ground loop is created that communicates with this bus.

nuuuu

"recommended" is not the same as "required!" or "necessary!"

Moreover, in this paragraph there is no phrase "..in the place of separation of the PEN conductor ...", it is recommended that you ground EVERYTHING and EVERYTHING if possible))) (after all, potential equalization and electrical safety increase)

In addition, the PEN conductor in a multi-storey building in the main switchboard is grounded, which is what this PUE item “recommends”.

Moreover, if you look at the structural diagram 1.7.3 from the PUE, we will see that at the separation point of the PEN conductor there is no MANDATORY grounding, but the PEN conductor on the power supply is necessarily grounded.

Re-grounding is necessary in order to reduce the voltage on the open conductive parts in case of breakage. In the absence of re-grounding, there is a danger to people who touch the equipment that has been earthed while the phase is shorting to the chassis. In the event of a break in the neutral protective conductor and a phase shorting to the housing behind the break, this danger increases sharply, since the voltage relative to the ground of the dangling section of the neutral wire and the housings connected to it can reach phase voltage.

Then, according to the PUE in the ASU, it is necessary to make the "main grounding bus" (GZSh) for the "potential equalization system". Do you have it there?

PUE 1.1.17: "The word" recommended "means that this decision is one of the best."

)))) Well, to the end, at least add the rule item))

Word "recommended"means that this solution is one of the best, but NOT MANDATORY !!!.

Well, in principle, I said, for equalization of potentials.

I agree that in the event of zero burn-out, there will be a danger, but apart from recommendations for installing additional grounding, PUE cannot offer anything.

Again, on my own I can once again propose a minimum voltage relay at the input, with phase discontinuity and zero.

amendment))

not undervoltage relay

and the voltage control relay, because the voltage of the m / y phase and zero can not only fall but also jump))

Have you checked the presence of re-grounding at the entrance to the building, the condition of the main PEN conductor in the riser, its cross section throughout? Are you fully confident in the reliability and speed of your voltage monitoring relay in different emergency situations? Then, do you have a potential equalization system? How and where did you connect it? In general, there are too many nuances and any energy inspector your initiative will turn against you at the first opportunity, I’m not talking about the danger of everything that you did with your wiring. On this, I think the question is settled. In the future, only comments are accepted regarding the possibility of installing an RCD in a two-wire system (with the TN-C system).

ok))

Based on what you have said, Andrei, the probability of the appearance of a “phase” on the case of electrical appliances in the apartment when the PE conductor breaks in the floor board even with the TN-C-S system is very high. And the RCD will not work until there is a leak, including a human touch. In this case, TN-C-S from TN-C is no different. My personal opinion is that RCDs must be set. At least in two (four) wire system, at least in three (five) wire. It really will not be worse. But it can easily save a life. And in the version when sitting on a wooden chair standing on the lacquered floor, grab for zero and phase, and with TN-C-S, the RCD will not save ...

Of the two options that are proposed for consideration (to put an RCD or not to put in the TN-C system), you need to choose the one that increases the likelihood of a person surviving when exposed to voltage. Therefore, the only right solution is to install an RCD, of course, with a clear understanding that in the TN-C system it is not 100% protection. By analogy, if you had the situation to jump with a parachute even if it might not open up with some probability and jump without it, then all mentally normal people, and this is quite natural, would choose the first, since in this case you are much more likely to stay alive. Conclusion: RCDs in the TN-C system must be set!

I agree that it is better to set and nothing better to separate any conductors. After all, we are talking about life and there’s nothing to argue about anyway, when a person touches any kind of conductor, a leakage current will appear and RCDs (if it is of good quality, it’s better not to save) will work. And the possibility of simultaneously closing two conductors, here no grounding system can save you.

What an "empty" article. In general, this is an RCD nonsense. As Zadornov said: "Well, those dumb ones." All the way they lived with the AP and grounding the current leading parts or parts that could be under U, a simple jumper. DO NOT POOL FINGERS IN THE SOCKET ALL THAT REMAINING IS REFLECTED TO THE NEWSPAPER. Oh, these Judas from scratch will suck sperm with blood from a finger.

Sergei, and even earlier people lived in caves and cooked food at the stake, and at times they also ate meat from their colleagues in the cave. Maybe it's worth returning to these times? Judas was definitely not there yet, and no one wrote "empty" in the articles.

RCD is not "nonsense", but a really useful technical device that saves people's health and lives.By the way, such a concept as protective shutdown and its technical solutions ensuring it were used in the USSR in the 1950s. True, domestic RCDs began to be used with us much later. For this, the Rossiya Hotel should first light up. So industry was set up in a large country - the USSR, that more or less normal technical developments were applied primarily in the military industry, then in industry and, by the residual principle, in everyday life.

And if you refuse to progress, then in this case you can’t use any electrical appliances and devices that require zeroing in the apartment, since it is simply absent with the old TN-C system. Where and where will you throw the jumper? So throw away your computer and washing machine, put your favorite AP and a 100-watt incandescent lamp. And everything will be wonderful - simple and reliable. Yes, and you can boast with your neighbors that in this way you are fighting with the Jews.

It is NECESSARY to set the RCD in TN-C systems, well, the voltage control relay will not hurt one hundred pounds (a friend burned out a null - the computer burned out, t.p., dvd and, by the little things, he quickly put a voltage control relay on, picked up zero, but badly, in As a result, the neighbors again got to repair household appliances, and a friend just sat with the voltage turned off)

Kak ya predstavliaju takie statji dolzny pisatsia takim obrzom ctoby citajuscij ciotko znal kak nado delat. To cto napisano mne bolshe poxoze na literaturnoe prоizvedenie. Pri tom escio s osybkami v elektrotechnike, a koe gde s yavnym neponimaniem suti dela. Na cto v obscem i ykazali komentiruescie. Tolko vot bukv mnogo - polzy malo.

Sorry for the Latin letters. Writing Cyrillic takes a lot of time.

siGis, What exactly do you disagree with? What mistakes did you find? It is possible in more detail, only, preferably, not in translit. I just really would like to see a more detailed and decrypted commentary, especially about the "important misunderstanding of the essence of the matter." What is the point?

Opinion: RCD + voltage relay (domestic, since industrial (for ATS, for example) has a longer response time).

Question: here they talked about the defective grounding of the protective conductor, which was obtained from the working neutral in TN-C systems. It is definitely impossible to make changes to the counter, therefore, the neutral must be grounded again after the counter. But in this case, when zero is burned off at a substation or transformer, a zero operating current will flow to your neighbors through your repeated grounding.

ps An example with a simultaneous touch (when using an RCD in a shield on a two-wire cable) to a phase and neutral lead was made (in general, like the whole article) to prepare the reader for an advertising of RCD outlets.

I do not mind such decisions, since I myself bought such “plug-and-socket-UZOs” to different people (including relatives and friends) in old apartments.

ss Thanks for the article, I used to meet only "fork RCDs". Rosette RCD also looks good.

... "Question: they talked about the faulty grounding of the protective conductor, which was obtained from the working neutral in TN-C systems. It is definitely impossible to make changes to the counter, so the neutral must be grounded again after the counter. But in this case, when the null is extinguished at a substation or transformer, through your re-ground, zero operating current will flow to the neighbors. "

Re-grounding "zero" is done on all "complex" supports, i.e. anchor, including without fail on the first and last in line. Re-grounding is also done without fail before entering the meter through a piercing clamp. It is grounding. These are modern requirements.

vitaliy, I do not understand what does the counter have to do with it? The PEN wire must be grounded at the place it is divided into N and PE: https://i.electricianexp.com/en/shemaTS-C-S.jpg

This article is not an advertisement, but a search for a simple way out of this situation. The main need to install exactly RCD-type outlets is not the danger of simultaneous contact, but the need to eliminate the constant tripping of residual current devices installed in the switchboard due to old wiring.By the way, the outlet RCD in the picture is ABB (I did not mention the name of the company in the article), but other manufacturers have such RCDs.

andy78,
I was a little mistaken, with a very good re-grounding of the working conductor, in a normal situation (without any breaks at the substation), the neighbors' working current will flow through your ground.

about the picture: now answer where the counter should be in the picture? After all, the presence of a counter is necessary, if I'm not mistaken ....

Gorynych, Requirements - requirements, Caesar - ....

Having a private house, two wires come from the pillar to the counter. After the counter, I pull three wires. Third (protective) I do not connect to working zero. That is what was meant.

In an apartment building, re-grounding is brought to the ASU, where N and PE conductors are separated. As a result of this, we get a five-wire riser on the floor shield. After the counter, three wires enter the apartment.

In a private house there are two options: separation of conductors on a support from which a branch is made (re-grounding is also applied there) or on an input device to the house. Repeated grounding is connected to the input device. The counter is set after separation of the conductors and the creation of the TN-C-S system. Why do you need re-grounding I already wrote.

Cool. The simplest theft scheme: the incoming zero bites off the counter, the zero departing from the counter bends off the zero bus, the PE jumper jumps to the zero bus ...
We started from the PEN separation and return to it: the separation does not occur on PE and N, but on two N. At the same time, one working zero - honest, the second as PE - brings zero potential to the case (in the socket to the ground contact (there are nuances, t .k. at zero, in contrast to PE, the potential is non-zero ...) and, say, gas cooking surfaces are better not to nullify ... in the house (we’re talking about old ones) there is no grounding in the ASU. Grounding occurs in the TP (cable entry), either on a support (branch from a support). Zero in the ASU comes immediately to the grounding bus (it is there alone)
vitaliy: you have a TT system - short-circuit currents - small. An RCD is mandatory, and even put at 10 mA, if the house is in the sector where the old houses are, it should be done just like that, otherwise, due to a break in the pole, your grounding may not be able to withstand currents coming from neighboring streets ...
The TN-C-S system is to see our invention (wrap shit and declare, and we have the same as you have in the West) from this TN-C-S there are one problem - the wires are the same - how to distinguish them? and who will mix up and change your S from C? basically that's why it hits ...
RCD is an ADDITIONAL protection against direct contact, it has never been a panacea. To install sockets, I think this is too much, but as adapters to the outlet - very much so.

andy78, what you need is not a question. The question is whether for many subscribers the separation is carried out on a support? A five-wire riser is the norm for "new" buildings.

If in old houses there are only three phases and a "housing" of the shield, then where to connect the protective ground?

He held out a new three-core cable for the boiler in the "old" house. He left the old wiring unchanged. RCD installed on a new cable not in the shield, but already at the entrance to the apartment (there was not enough space in the shield, the phase of the new cable was connected to the existing machine). Protective grounding taken from the shield housing. Indeed, when the "disappearance" of zero can cause an emergency. So you need to put a voltage relay.

Dear admin! In the bathroom I did the wiring and connection of the washing machine myself. The power wire, although in cambric, but goes down, where it is sometimes damp and therefore slightly "breaks" into taps and water.Not just beating, but feeling enough. In this case, I immediately turn off the 15 amp bag, facing the power outlet of the washing machine. The phenomenon disappears. Advise what else can be done?
Pihtelkin.

AlexanderIt’s best to ground the conductors and attach re-grounding to it on a support, since if you do it at the entrance to the house, then when the zero on the overhead line is burned out, all the line neighbors will be fed through the zero wire of the input cable, which can lead to the combustion of the cable itself . And I completely agree with everything else.

vitaliy, in old houses it is not advisable to take the PE wire from the shield housing. In order to remake the apartments of the old house for three-wire, you need to upgrade the switchgear and the entire riser. Protective grounding must be connected to the switchgear, and then pull five wires in the riser. But all this should not be done by the owners of the apartments and only by the organization operating the house.

Viktor, I put the corrugation into the cable in the bathroom in the bathroom on the ceiling, then lowered it into the outlet to the outlet. There are no problems yet. Yes, be sure to put an RCD on this outlet, as the presence of an outlet in the bathroom is not very safe, so if it is possible to take the outlet outside the bathroom, then this should be done.

andy78let's take a real look at things. some houses are more likely to completely demolish than make sensible grounding.

about re-grounding. if re-grounding is better than at a substation / transformer, the meter may not "wind up". This is one way to steal electricity. Although modern counters take into account phase and neutral currents. So when using working zero from the ground, a red LED will light on such counters.

1) read the PUE: 1.7.73, 7.1.87, 7.1.88, 1.7.35, 1.7.36, 1.7.39, 1.7.47
2) in the reinforced concrete wall of the apartment on a plot of 150 x 150 "dig" to the fittings.
The depth of its 50-100.
We weld-solder a contact to steel, and a wire to it.
This wire is connected to the apartment PE-network.
3) at the input, in series with the machine, we put the electromechanical RCD,
par value on a step of par rating machine.
4) in series with them we connect a voltage monitoring relay of the type
"Resanta AZM-40A" or something more "medical assistant."
With a zero cut and an increase in U more than 265 V, the apartment network will be de-energized for 2-3 minutes.
Deadly considered 100mA.
The RCD will shut off at 30 mA, that is, most likely (!), It will save your life.
If you take the phase and zero with wet hands and stand on the insulator yourself, then no RCD in any system will save you.

The purpose of the article is also incomprehensible to me. The question is whether to put RCDs the most primitive of all questions on electrical safety. To put, always and everywhere in residential buildings with any TN-C or TN-C-S power supply systems. And with two wires and with three wires. There is always real benefit from it.

There are some moments when the PUE directly prohibits the use of RCDs (or restricts their use), but this has no relation to residential buildings.

To say that RCDs need to be installed only with the modernization of the electrical wiring can only be limited and illiterate in the technical sense.

In regulatory documents, this issue has been resolved for a long time unequivocally, without any options. I can name two of them:

"GLAVGOSENERGONADZOR LETTER OF APRIL 29, 1997 No. 42-6-9-ET ON THE INTRODUCTION OF" TEMPORARY INSTRUCTIONS FOR THE USE OF UZO IN ELECTRICAL INSTALLATIONS OF RESIDENTIAL BUILDINGS "

SP 31-110-2003 DESIGN AND INSTALLATION OF ELECTRICAL INSTALLATIONS OF RESIDENTIAL AND PUBLIC BUILDINGS

In case of false positives of RCDs in buildings with old wiring, it is necessary not to disconnect RCDs, but to look for the cause of leaks, because they ultimately lead to short circuit or fire.

In general, I don’t understand what can be discussed here, RCD is necessary in every apartment, these are the saved lives of people.

As for the separation of PEN into PE and N conductors, it is clearly and rigidly defined in the PUE. There are two main conditions: the cross section of the PEN and its continuity. Grounding at the separation point is good and reliable, but according to the PUE is optional, and in life it is often impossible at all. But this does not mean that this should be abandoned.

RCD has a panacea for the user. Pointing out that under the rules of RCDs it is an additional protection for direct contact, you forgot to indicate that INSULATION will be BASIC in this case. In the normal case, isolation is always present, but direct touches do happen.

It should be noted that according to the rector of Rostekhnadzor V. Shatrov, this option is possible only when feeding a private house from VLI (SIP). If the overhead line is made with bare wires (ordinary old overhead line), then only the TT grounding system must be used. No PEN with OHL can be brought into the house, no re-grounding at the entrance to the house, only a separate own grounding and at the input of an RCD of 300mA for automatic shutdown.

These and other recommendations of famous experts and authors of regulatory documents can be found in the journal NET (Electrical Engineering News) and its annexes.

Bet everywhere? Hmm ... But what about the PUE?

1.7.80. It is not allowed to use residual current devices that respond to differential currents in four-wire three-phase circuits (TN-C system). If it is necessary to use an RCD to protect individual power receivers that are powered by the TN-C system, the protective PE conductor of the power receiver must be connected to the PEN conductor of the circuit supplying the power receiver to the protective switching device.

Both the ground loop and the neutral wire in the switchgear and at the substation can burn (rust), especially since in Russia they operate electric networks. But no one will ever give an absolute guarantee of your safety in terms of electric shock, at least plug five grounding conductors into the apartment. But it doesn’t seem to me to completely rely on one UZO either, if only because you buy it in a store (who produced it, how it was delivered to the point of sale where it was stored, nobody will tell the truth!). It’s good that before installation in the shield, the RCD and any other protective device must be loaded to find out if the operation of this device corresponds to the data declared by the manufacturer in the passport and whether the results obtained are in accordance with the standards. Only who will bear the extra expenses for trials in the personal economy? Moreover, the matter is not limited to testing newly installed protective devices, it is necessary to check the characteristics and then, periodically during operation, and you say an RCD to each outlet))).

"And what if, with the old wiring, the RCD will constantly de-energize the apartment?"

How to do what? !!! Search for a reason. Do you have a leakage current and you don’t know where or what? RCD in this case is generally the best special. Look for it! Where and where?

This is dangerous in all cases and with any network systems, since all power consumers are connected in this way. The presence of an RCD gives a small chance that the leakage current will exceed 30mA and it will work. So in this case, the RCD is an indisputable plus.

Old wiring is not so bad.Plaster wires as new. There are problems in the distribution boxes. It’s brainstorming, fixing.

Why??? Only here and need to be split. The shields (how many I came to see them) are iron and are always grounded. Earthed - this does not mean that for each piece of iron a stake in the ground is clogged. Zero is a separate wire and is also connected to the shield body. Those. zero is re-grounded. Grounding should be periodically measured. Burning zero does not mean burning grounding. Unless in extremely exceptional cases. When splitting, it is very important to connect the ground conductor to the housing with a separate bolt. In no case with zero. The difference between zero and grounding after splitting will be precisely that during normal operation no current will flow through the grounding wire. It will perform only a protective function and will not burn anything there.

The difference between an RCD in a two-wire network and a three-wire network is that in a three-wire network you get additional fire protection for electrical reasons.

The conclusion is unequivocal - RCDs must also be installed in a two-wire network. At least there are no serious, well-reasoned reasons for not doing this yet.

The question of whether or not to put an RCD was raised only because letters regularly come with claims that it is forbidden to put RCDs in the TN-C system according to the EMP, and you advise to put it in your articles. And then a formidable lecture "read the PUE, and then write your articles." Here, too, someone Aleksey had already noted the same type of comment with a famous quote from the PUE. Having read such formidable letters by me, an attempt was made in the article to sort things out.

andy78

It seems that in the EMP it was a question of the fact that if you divided the “fourth” conductor into two (neutral and ground) in the TN-C system, then in the future they can not be connected together.

I’m afraid the problem is not in the cable, but in the fact that when dampness appears, the potential appears on the floor from the body of your machine, when insulation is dry enough, but these are grimaces of TNTs, I already wrote - a phase is possible on the case, maybe a phase through something .. .
Try to unhook the "ground wire", pick up the washer through an RCD, this should help ...

They write about separation on N and PE on poles, what nonsense .... What in a private house does not make a simple triangular ground loop, it's easy, simple and will be real PE.

And in the floor guard, in fact, N separately comes from a nut (branch compression))), and the case is grounded, so you can use the connection to the case as a similarity to PE, and it will be correct. True, no one probably measured the ground resistance of the shield .....

It is on the PUE and set. I can tell you another point where it says when it is impossible to put an RCD, but this does not change anything. We are talking about residential buildings, about apartments, where according to the PUE UZO can and should be set. Try to carefully read the paragraph of the EMP indicated by you and find the reason why it is forbidden to do so in it. And what needs to be done so that the RCD can be set in this case too. The answer is on the surface.

Not loading :) but checking for the actual diff. tripping current. If this is the RCD concerns. It is quite easy and cheap to check the operation current yourself if you have elementary skills. The speed is more complicated here, but to make sure that the RCD works at a current of 30 mA is elementary with a resistor of about 7 kOhm. In principle, the built-in check from the "test" button also works.

Let the lot understand the PUE :), and not make claims on misunderstood items. This paragraph refers to a three-phase 4-wire system with the grounding of this 4-wire. A three-phase RCD breaks all 4 wires, together with zero, which is protective in this case. It is forbidden to break the protective conductor in all versions of the PUE. From here follows the second part of this paragraph indicating that the RCD can be applied if the protective zero is taken before (in front of the contacts) the RCD.

This debate has unfolded))

Where is it written in the regulations that requires grounding at the PEN separation point of the conductor?

Not for the sake of argument, other opinions are just interesting.

I will tell you right away that there is no such thing anywhere in the standards. There is no this in PUE, not in state standard specifications, not in SNiPs. There is a minimum PEN cross-section of 10 square for copper and 16 for aluminum. Enough - can be divided.

Re-grounding is required only at the entrance to the building and then with reservations. Even the magnitude of its resistance is not always regulated.

Another thing is that such a solution (separation at the grounding point) can provide maximum reliability, better security. Especially in the disgusting state of power networks.

But, for example, in houses with electric stoves, grounding of electric stoves was always done and at the same time they used the same four wiring in a riser. If anyone was lucky, then the shield was connected to the ASU shield not only by zero, but also through the disposition system.

Therefore, if in the kitchen there is a grounding of an electric stove, then why not ground the rest of the apartment in the same way? A cross section of zero there usually allows such an option.

But if the zero in the riser has a section below the minimum acceptable, or the general condition of the house network is terrible... then there is reason to think: do you need three-wire wiring in an apartment with grounding in sockets before overhaul or reconstruction of a common house electrical network. Then it is better to leave 2 wires with the installation of an RCD, this is how standards are recommended, as a temporary measure before reconstruction.

These are not grounding systems, but power supply systems, after this distortion of exact science and everything else does not deserve any attention. Then, when the PUE recommends an RCD, it is not mandatory, in most cases excessive stupidity. It is a favorite brainchild of fire inspectors, as is actually an insulation control device. In networks with a grounded neutral - this is a money divorce.

Stupidity rather such statements.

Protecting people's lives and health cannot be stupid in any way.

According to PUE:

A better solution cannot be "stupid."

Instead, it would be nice to hear why, in your case, you need to protect users from:

1. direct touch

2. indirect touch

What is real except RCD capable of protecting a person in these cases?

As for the fact that the RCD is only recommended in the EMP, read section

"7.1.82. Mandatory is the installation of an RCD ... "

as well as 1.7.78.

Dear users, you argue about things that really exist and protect us from our own stupidities.So far, at the moment, the application of the Uzo solution is optimal, in addition, it does not require any fantastic investments.

What is the difference between the RCD outlet and the RCD in the ASU? Nothing, the same dangers here, the same division of PEN. Maybe pull this ground into this outlet?

Arthur,
I also don’t see the difference, the topic is sucked from the finger.

You can share pins in a floor board!
How do you think all electric stoves are grounded?

please tell me - I changed the old wiring to copper (3-wire) the question arose where and how to connect PE. The house is old, the system, as I understand it, is TN-C (4 wires in the shield). Is it possible from the basement, having scored a separate pin, to organize PE in your dashboard. What to put on the washing machine of an UZO or Dif if you still have to leave the two-wire version

Sergei, Yes it is possible, BUT if you have plastic pipes and with the same PE conductor connect all conductive structures that may be energized (bathtub, faucets, batteries, etc.), thereby making your own potential equalization system, and PVC pipes are necessary to isolate your grounding from external possible loads.

Andrew, in no case, it is impossible, firstly, none of the inspectors of energy supervision will allow this, and secondly, it is a time bomb, sooner or later an accident may occur before your separation of the PEN conductor and then the same plate will be energized. Such grounding is DANGEROUS FOR LIFE !!!!

Already answered this question that there is no such requirement in the standards. It turns out to be wrong. There is such a requirement, but it has been voiced ... somehow it's not bold))). Here is GOST 50571.1-2009

https://i.electricianexp.com/en/main/voprosy/426-uzo-v-dvuhprovodke.html

See 312.2 Types of system grounding, TN-C-S network diagram and description. I quote:

So there is such a requirement in GOST, but it is not clear why it is still not in the PUE.

I'm wondering how you will divide zero in old houses where fungal plugs still stand :-), it’s dangerous to touch them), and in the floor board I still don’t understand how you divide zero? or even I didn’t finish), if I'm still a beginner in electrics)

There are so many talking places, but for a simple person nothing is clear !!! I do not understand why this boltology? You can simply write: When two-wire is allowed, the installation of an RCD is allowed (although the PUE on this occasion is quite contradictory information. It can be seen - the same "specialists" wrote like this article). For this, in extreme cases, the neutral wire BEFORE the RCD is divided into N and PE. Phase and N go to the RCD, and PE goes around the RCD to the installation ground terminal. Of course, this method is not very reliable, but as an option to install an RCD in a two-wire installation. I have been working for 3 years, no complaints.

Something is not very clear the essence of the issue. When you take up the zero and phase wire, and even stand on the insulator, this means one thing - you voluntarily agree to become a TV or a washing machine, or, at worst, a coffee grinder!
Why should an RCD work? Then it should work when any load is plugged in and exclude, in principle, the possibility of using electricity. And what's the difference, what is your grounding system ....
As for the false positives of the RCD. I agree with those who believe that in this case it's time to repair the wiring. Or, at worst, again, by checking the circuit. Because if the RCD trips "false", then there are leaks, then there is a problem.

As for the installation of RCDs, I have no doubt - to put, of course, it is necessary, God saves the safe.
But the TN-C-S system is not entirely clear, since many talk about mandatory additional grounding at the PEN splitting point, so it is cheaper and easier to do this in the ASU. Probably, this is more correct, moreover, the PUE recommends this approach. However, he does not insist. On the other hand, what to do with the millions of residents who live in Soviet houses and who are the majority? Wait for the modernization of the power supply of these same houses? I am sure that many people will not at all wait for the moment when, changing their wiring in their apartment and cleverly leaving the third wiring in yellow-green isolation, they will throw it on a normal PE-conductor. This is not an unfounded statement: the house was capitalized, the filling of the ASU was changed, the risers were replaced, the machines were all as expected, with copper, and the line remained the same four-wire. The question is, why didn’t they throw the fifth PE-wire, didn’t clog the circuit? They answer: and so a lot of money has gone, do you have a bad life before that? But in the PUE there are lines about the mandatory departure from the TN-C system (when possible), and these lines are not advisory in nature. So you watch how people save expensive equipment, which, in order not to break, must dump part of the currents into the PE conductor, by connecting the so-called ground to the bolt on the floor plate, directly to the working zero, that is, breaking off from it.
In this regard, the question to the author: I saw in the comments the proposal to ground as well from the shield, but not on a bolt with zero, but under a separate terminal (bolt). How do you look at this, is the shield grounded, is it worth it to fear the occurrence of a phase when zero is burned out, and does it change anything at all?

Mandatory requirements and recommendations for the use of residual current devices (RCD) are given in Chapter 1.7, Sections 6 and 7 of the Electrical Installation Rules of the seventh edition. Clause 7.1.84 of the Electrical Installation Rules states that “in order to increase the level of protection against fire when shorted to grounded parts, when the current value is insufficient to trigger the maximum current protection, it is recommended that an RCD be installed at the entrance to the apartment, individual residential building, etc. with tripping current up to 300 mA. " In the Moscow city building codes MGSN 3.01-01 "Residential buildings" the requirement to install an RCD at the entrance to the apartment is mandatory. In the annex to these standards, various variants of schemes of apartment panels with the use of RCDs at the input and on individual group lines are given. It is advisable to use RCDs at the entrance to wooden residential houses and cottages, to apartments of residential buildings, the structures of which (beams, floors, etc.) are partially made of wood, while fire and burglar alarm devices should be connected in the circuit diagram after the counter to the RCD through the circuit breaker. Examples of the implementation of schemes of apartment panels with various connection options for RCDs are shown in the appendix to GOST 51628-2000.

TN-C set it off, during the repair connecting the lamp forgot to take off.

I stood on a stepladder on an insulated floor, grabbed the phase and zero, I know that I was bogged down, I always need to start working with one hand, I wanted to straighten the wires from the cable, it worked clearly, but I managed to grab a portion of the energy boost.

The author wrote everything correctly, the article explains well to morons electricians why it is impossible to separate PEN in the apartment panel. Only a moron can throw some jumpers from scratch to protect equipment.
READ CAREFULLY ONCE AGAIN (especially for jamshuts and any morons that cause fires) AXIOMS:
1) In electrical installations of residential buildings with the TN-C subsystem, PE separation from N can NOT be done. When zeroing off in the main floor, one floor below, etc., the phase potential will be on the metal. the case of the connected equipment, while the voltage relay does not counteract this.
2) RCDs must be installed everywhere in any grounding system.When two-wire RCD will work no worse than in three-wire (despite the fact that the device is of high quality)
3) From direct contact with the phase and zero coming from the RCD, the operation of the RCD will not occur, because RCD will consider a person a normal load.
Author, write more of these articles and explain to the jamshuts how to do it.

2 Afftor

It seems to me that you need to republish the article, taking into account all the above comments, that is, write so that there are no unnecessary questions, and, judging by the comments, there are too many of them.

I propose to understand the following:

1. Why PUE forbids RCDs in TN-C.

2. How the phase voltage gets to the case when the zero burns out (one floor below, for example). It is better, of course, to illustrate.

3. How to upgrade / connect RCDs in old apartment buildings, in private houses.

I drew a diagram of possible situations in an apartment building, where protective grounding is taken from the shield housing in the front door, where there are only four wires (three phases and a combined PEN).

Indeed, when zero burns down a floor below, the phase enters the housing through the load of a neighbor (the bulb is turned on).

The voltage relay will trip (since there will be a potential difference of 380V) and protect the equipment, but the phase on the case will remain (from a neighbor). The RCD also does not help, since it interrupts the zero-worker and phase (which could also be interrupted by the same voltage relay).

More about RCD:

30mA is a graded tripping current, that is, it actually trips earlier. I didn’t check on myself, but they said that it hits 30mA very much. For a child, such a blow can be critical. So on the "30mA" is better not to wear too much. 16mA is considered a pain (or "non-releasing") current. There was a case when I was "pinched" "strongly", but the RCD did not work.

Sorry, if formally, not quite on the topic of the article, but since the issue of re-grounding is already touched ...

Source:

Two-wire wiring in a village house (TN-C?). In order to increase operational safety and protect against breakdown of network cards and for the correct operation of the equipment’s built-in network filters, grounding was made at the connection point (that is, at a socket): the grounding contact is connected by a copper two-wire wire driven into salted ground underground to a depth of 1 , 5 meters with a metal rod. Measurement of the voltage between the ground and the phase in the outlet showed the same voltage as between the phase and zero. There is no voltage between the “zero” and the “ground”.

Questions:

1. Does it make sense to connect the “zero” (PEN) and the grounding terminal in the socket with a jumper (to “ground”) in order to increase the reliability and speed of operation of the RCD (in case the grounding resistance increases over time)?

2. Will such a circuit be considered safe and consistent with the TN-C-S re-earthed circuit at this local consumer connection point (outlet)?

3. Will the grounding and “zero” with such a connection (and with the condition of maintaining the minimum resistance of the grounding loop over time) actually duplicate the functions of each other if one of them breaks?

1. Doesn’t, 2. Will not, 3. Will not

Jacob, it is formal, but in fact?
And - why, (if not difficult).

The PUE prohibits the installation of RCDs in the TN-C system, except when there is a third wire in outlets that is connected to the RCD. But then the connection point of this wire actually converts the wiring in the apartment into the TN-C-S system. But where to connect? On the landing there can be a shield, or maybe a box with branches to the apartment - to connect suicide to them, especially if it burns out zero on the riser, it is even worse and more useless to connect to the water supply system or to the fittings in the wall, there is only a connection to the pot with a cactus. The reason for the prohibition of the use of RCDs in two-wire is simple.There are international standards and norms and GOSTs developed on their basis. According to them, the response time of the RCD is no more than 0.3 seconds. RCDs can work faster, but the worst case scenario is taken into account. According to GOST - a conditionally safe touch voltage for household electrical installations with a power off time of 0.3 seconds corresponds to a touch voltage of 70 volts and a current of 70 milliamps. In the absence of a protective conductor, the case can be all 220 volts or more, and this corresponds to a current of 220 milliamps and a shutdown time of 0.02-0.08 seconds. RCDs do not have time to disconnect so quickly, and therefore it is forbidden to use. It is especially difficult with a washing machine installed in a bathroom, a particularly dangerous room. Yes, here UZO is not a defense, but a desperate attempt to save a life. But on sale appeared special UZO for washing machines - UZO-DPA-16V. You can use TWO RCDs - one for 10 milliamps for a washing outlet and one for 30 milliamps for the entire apartment. But always two in view of the particular danger. Moreover - such a measure of protection may even be sufficient and comply with regulations. But here everything is individual. It is necessary to measure the resistance of the leakage current of 220 volts through water and the sewage system to which the washing machine is connected. If the leakage resistance on a washing machine not filled with water is measured on a drum with a ballast from an outlet — about 1000 ohms — everything is in order. If the insulation is reduced before RCD tripping, the contact voltage according to GOST-12 is 12 volts and the current is 2 milliamperes, and the response time can be more than 1 second. At 220 volts on the case, it trips in 0.3 seconds, but the bottom line is that the participation of the human body in This process, as it would be in the absence of a creepage path, is not necessary. It will work on its own. Or 30 milliampere RCDs may work - it is designed so that it triggers a little earlier than the setpoint, plus leaks in the apartment - it may be 2-3 milliamperes before it trips. In general, security should be considered as a set of measures. For example, they put a protective screen on the heating battery, and the room is already without increased danger. Here, for each apartment, everything is strictly individual. But it is better to put an RCD - there will be no harm from it, it can at least protect it from a fire.

Dear! To consult ...

I plan the wiring in the new big bathhouse. I read all these discussions with grounding issues and I think that in my case it’s easier to galvanically get rid of the collective farm network. In addition, the voltage in this network can drop to 175V, which is not good.

Therefore:

Immediately after the input machine and counter - a 5kW stabilizer (it’s not very expensive right now, 3-5 tr), and then to group machines and dissolve it. The lighting in the steam room and shower room is 12V (LED? Halogen?) Through a power source located close to the input panel. RCD or differential automatic devices are not provided. The grounding device is optional (?). Yes, the reliability of the stabilizer and IP is a question. Campaign must be reserved.

I sincerely ask you to express your opinion.

knotik,
if a person touches both the “0” and the phase at the same time, then the RCD will in principle not work, since there will be no differential current! The currents in the zero and in the phase conductor receive the same increase - the leakage current through the human body.

Hello. I would like to know your opinion. I work in a high-rise building of 360 apartments. The house is only 8 years old from the date of construction. In each apartment is el. shield with summed up three phases and is divided by a group of machines including RCD. For 3 years we have 4 fires of electric guards and the guards are burning with RCDs. How can this be explained and have you heard of similar cases?

Semen Deruzhinsky,

and RCD, of course, with a clear understanding that in the TN-C system it is not 100% protection.By analogy, if you had the situation to jump with a parachute even if it might with some probability not open up and jump without it, then all mentally normal people, and this is quite natural, would choose the first, since in this case you are much more likely to stay alive. Conclusion: RCDs in the TN-C system must be set!
I completely agree! Loved the parachute example! I will now cite your text as incontrovertible evidence to especially stubborn opponents of RCD!

andy78,
I have a 3-room apartment (I don’t count stoves), ASTRO UZO F2111 25A 10mA is on a two leash (TN-S)! It is already 9 years old! House and wiring since 1974! Nothing in vain did not work !!! THIS IS AT A SENSITIVITY 10mA !!! It worked twice when the electric heater in the electric titanium burst-burned out from old age and scale. Water is terribly hard! It requires cleaning of the heater and titanium 2-3 times a year! IF IT WASN'T THIS UZBE, IT IS POSSIBLE WHO ANYONE FROM HOME NARROWS, OR EVEN THAT WAS NARROWED DURING WATER PROCEDURES !! ONE TIME NEIGHBORHOOD WAS FILLED WITH HOT WATER. WE HAVE NO HOUSE! IF THERE WERE NOT A UZO, THERE WOULD THE CARDYK COME TO THE WIRING! And so they came home to a wet apartment - there is no light. Of course, they didn’t turn it on, dried everything in five days and turned on the RCD. Everything has been working for 3-4 years! I know from experience that in such cases, wiring without an RCD closes and even burns out in several places !!! UZO IS USEFUL IN ANY EVENT !!! EVEN WITH THE "IT" SYSTEM, AND IN THE "TT" SYSTEM JUST REQUIRED! ONLY WHEN WE ALLOW A KIOSK FROM A METAL, IT IS NECESSARY TO MANDATORY A SELECTIVE UZO AT A SUPPORT OR IN THE PLACE WHERE THIS METAL Kiosk IS WATERED !!! And then they put it after passing the input cable through the metal roof, metal pipe stand (gander), through the metal case of the kiosk, through the SHU-RSH case, through the opening sealed automatic machine and counter !!! AND ONLY THEN RCD !!! Everywhere along this path, insulation with phase closure on the kiosk case may be violated, and the RCD will be with such a distribution on the side !!!!!

There is one jamb on my part. - I can’t do any overhaul. Well, the new wiring, respectively.

Alexander,
Paul. For example, I could recommend in the SHU-RShch or on a support, before combining the earth with zero, put two or four pole input circuit breaker for example 25A. This is not the PUE of course. Take a moment !! In this case, the short-circuit current to the ground loop (without a working zero) should be more than 25A. THEN WHEN THE "MAIN" WORKING ZERO TURNS OUT IF THE EARTHING CIRCUIT WILL NOT CONTROL THE LOAD FROM OTHER HOUSES - THE AUTOMATIC CIRCUIT WILL DISCONNECT THE PHASE AND THE ZERO AND HIGH ON THESE ARE EMERGENALLY EMPTY! LEAD THEM AS A RULE, NO EARTHING, NO RCD, AND NO PROTECTION FROM OVERVOLTAGES DO NOT NEED !!! The main thing is that they are not judged by current, God forbid! And it may be wiser. At the same time, you will not get electric current from electric equipment cases, and your equipment will remain intact.

My invention.

pvp,
and RCD, of course, with a clear understanding that in the TN-C system it is not 100% protection. By analogy, if you had the situation to jump with a parachute, even if it might with some probability not open up and jump without it, then all mentally normal people, and this is quite natural, would choose the first, since in this case you are much more likely to stay alive. Conclusion: RCDs in the TN-C system must be set!
THROUGHOUT THE ROUND THINK ...........! BE MY WILL - I WOULD NOT ALLOW ALL THOSE TO ELECTRICIAN !!!
ME ALREADY TWO TIMES THE UZO MUZZLE FROM TAKING HAND HAND FROM PHASE TO THE GROUNDED SHIELD !! STILL NOT KNOWN - COULD I HAVE UNDERSTANDED UZO? YES WITHOUT CONSEQUENCES ???

Vasiliy
I think we need narrowly and three-wire with real grounding. RCDs need in your case a mechanical type A. It reacts to both alternating and pulsed leakage currents. UZO lush probably after the stabilizer. Earth can not be connected with zero. Let it be TT. Especially if grounding is crap. Paul.

Now there are many standards about RCD. Russia in this issue switched to Euro-standard. In projects of new and reconstructed buildings at the entrance to the apartment and outlet groups without an RCD, not one examination will not miss. Conclusion - RCD is required, because the safety of people depends on it. RCD also performs the function of fire safety, and this is not a little, since 50% of fires are due to wiring. During major repairs of apartment buildings, everything changes according to TN-C-S from the input to the apartment panel, with the installation of an RCD, then in the apartment the tenant changes himself or hires those who have a license for these works.

Sergei, with RCD or AVDT? The protective shutdown device is installed together with the circuit breakers in series., With rated parameters exceeding the parameters of the circuit breaker (current). Or the "hybrid" is used - AVDT.

I have a house of an old building, the 9th floor, we live in a communal apartment, when I made repairs in our room, I changed all the old aluminum electric. wiring from the floor electric. shield on the landing to the room 4mm2 on a three-wire copper according to the PUE and installed an electrical panel on the room with an RCD, it turned out TN-CS zero is divided into N, PE when entering the room (although this is not supposed to be according to the PUE), 2mm2- wiring around the room (sockets ) and 1.5mm2 (lighting) VVGng. When the second child was born and started walking, then an UZO helped (after all, peeping, he’ll fit everything), in general, at 1.5, he plugged into the socket with tweezers from the manicure and hit him, but The RCD tripped and cut off the voltage, which I’m overwhelmingly happy, then for 2 weeks I went around the socket, pointed at it with a finger and uttered UUUUUUUU with a frightened look. In general, it is necessary to put an RCD, and then in a similar case, how will you blame someone for yourself that you did not watch, that you did not put the RCD, your wife, that she removed the tweezers badly, or all the household, because you relied on them that they will look after ........

Correctly not a "grounding conductor", but a "protective conductor". And you can separate the PEN conductor with a cross section of at least 16 mm aluminum, or 10 mm copper.

I serve several cooperative houses built in the 70s of the last century. Moreover, all houses are equipped with electric stoves. Of course, there is TN-C. Moreover, for the grounding of electric stoves, the 3rd wire (PE) is laid (by builders), connected to the building in the floor switchboard, i.e. to N. In addition, the cable (primary and backup) supplying these houses is 3X120 mm2 in the sheath. this shell is used as an N - conductor. In addition, the houses were built, in fact, on a covered swamp, i.e. the depth of the groundwater is somewhere between 70 and 80 cm. In other words, the cables lie directly in the water. And the cable insulation over the sheath is tarred hemp. Those. I, as the electrician of these houses, have constant "meningitis" - sometimes it takes 2 hours to prove to the dispatcher of the RES that the sheath has dissolved in the cables and N. doesn’t come to the house. The questions are “How did you determine this?” etc. The previous head of RES had already promised to replace the cables with 4-wire, and the new head, pleasing to the top management of oblenergo, did not want to hear anything about it. The only thing they did was replace the terminal pieces of cables (10 meters each) that go into the input electrical panel with 4-wire ones, and the main body of the cables lying in the swamp remained old. So now I can’t even prove to anyone that there are three-wire cables in a sheath. And of course, regularly, every 3 to 4 months, he is forced to call an emergency gang, explaining to the dispatcher for hours that there is no N. on the house. It is especially scary when one of the phases burns out along with the shell. Then, between the N wire in the house and the water tap, the voltage is up to 60 -70 V. During one of these outbursts in one of the apartments, all the apartment wiring burned out (suspended ceilings were installed, and when installing the spotlights, wire N lay on the profile). Well, now about the RCD. Even in such conditions, I recommend tenants to put RCDs on outlet chains. (I think that putting an RCD on the lighting circuit makes no sense). It must be said that the energy inspection inspectorate issues prescriptions for mandatory installation of RCDs after meters that supply elevators and stairwell lighting. However, they do not care about the health and life of an electrician. The reason is simple - to prevent theft of electricity. And one more thing. Then one comrade in "Comments" complained that there was voltage on the washing machine. So, there is a voltage of about 110 V. there because a filter is installed at the input of the washing machine circuit, in which capacitors of 0.022 mF are connected to both sides of the washing machine after the plug, thus forming a capacitor divider that forms on the machine’s body voltage equal to half the mains voltage. Therefore, the PE wire of the washing machine must be earthed, or at least connected to the water pipe. (The current there is small, there will be no electricity to neighbors.) But I do not advise putting a jumper in the outlet on N.

While touching the phase and the working zero with different hands, at least with TN-C, even with TN-C-S (if the legs are well-insulated shoes), the RCD will not help here. For UZO there is no difference where it passes through the human body or another electrical device. If only there was no leakage in the amount of 30 mA to the ground electrode.

But do I have a triangle 220 at the entrance to the apartment, still a Polish trance, and what not to put a diffrel at all?

If you use a voltage monitoring relay in case of ZERO burning off, it immediately cuts everything off, I personally did it, five times it saved all household appliances with jumps above 252v, then RCDs can be used as an addition to safety in the TN-C system, at least least turns off the water heater with a broken ten, the washing machine with a broken ten I personally when the machine was working and the RCD was knocked out, I immediately realized that it was TEN and it’s exactly OH, or an electric stove with bursted comfort — I tried the RCD in practice, but if the hair dryer is working, drop it in anna water RCD may not work especially if the bath acrylic and drain made of plastic and not all hair dryers have PE Explorer even most do not have. Once, by chance, changing the outlet at home, I closed ZERO with PE, the RCD worked, despite the fact that I have a TN-C system.
I’ll get a little off topic, in general, it’s better to put old trouble-free calibrated inserts fusible instead of fancy circuit breakers, not in vain in all German machines and even new industrial washing machines I saw only one automatic machine (introductory), and the rest only fusible inserts and nothing more. Three times I witnessed when the machine did not work and the carrier turned into a Betford cord with all the ensuing consequences. It would not be bad for manufacturers to live. technicians install plug-in fuses designed for the cross-section of the wire to which this device is connected, imagine what will happen in the case of a short circuit with a 2x0.5 wire from an electric lighter for a stove that is connected to a socket that sits on a 16a machine, I saw it with my own eyes, the wire is just melted and caught fire emitting corrosive smoke, and the machine did not even work, well everyone was at home. Just doing the wiring, you need to carefully select everything according to the current loads and where what will be connected, and not so on the 16a sockets! Even shovel automatic traffic jams are more sensitive than some modern automatic machines, and why only Group-C machines are in stores, groups B or A are more relevant for life. Sorry, I moved a little off topic - I personally have an RCD working with the TN-C system as an extra. security.

About the washer, it really doesn’t pinch, but the plug must be inserted correctly, and the fact is that all real Euro plugs and Euro sockets are POLARIZED, that is, if you look at the socket on the right side of terminal L, on the left side of terminal N, top bottom of the PE terminal and no other way! in them you can’t just simply physically stick the plug in on the other side and the pin in the outlet that is strictly aligned with the plug will not give, but this is only in real Euro outlets, which in our case is the phase from the right, zero from the left, PE you know where, and insert the plug so that the recess in the middle intended for the PE pin is in the upper half of the plug - this applies to all washing machines, microwave ovens, refrigerators, computers, and everything that has a euro plug. It is not necessary to insert the plug on the other side of anything, if it has a radial cord approach directed downward, and because it is not convenient, it is inserted into the revolution, and then they say that it pinches me with electric current and most importantly I will reveal a little secret on some imported heating boilers if plug the wrong side to insert it, you’ll start the horse-radish - stop on the flame control, the plug is turned over as it should and everything works. I myself encountered such problems in the field of work Instrumentation and automation, people of the Hurls will invite - mullahs of electricians to replace the sockets, and those phases with zero will be interchanged in the socket by knowledge, and then people call that the boiler does not start, and it's only right to make the connection in the socket.

Pike
It is advisable to put an RCD even in the "triangle", since one of the phases can still be grounded - either directly on the transformer (as a rule, ground the phase "B"), but if the phase "B" is not grounded on the transformer, then the "ground" can come from other consumers.

Vitaliy,
As a rule, Chinese carriers are transformed into “Bikford cord” - extension cords bought on trays. If the carrying is real, then the wire there is at least 1.5 mm2, and there the machine will certainly work earlier than the carrying cord heats up a little. Personally, I make myself carrying myself: I put 2x2.5 mm2 on a more powerful load, in all other cases 2x1.5 mm2 is enough. Therefore, I repeat once again: do not "save" by buying Chinese electroheat on fake trays - fakes. More than once I had to reject Chinese carriers from customers - fakes they bought on trays. Externally, the wire is thick, as if there is 2.5 mm2, and in fact it turns out to be no more than 0.1 - 0.2 mm2. There was a case when the sewing machine included in the carrier "set" the voltage to 100 volts, and the motor did not spin. All this is really fraught with fire.

Vitaliy,
You are right in one thing that euro plugs are polarized, and you can’t insert them otherwise. However, the circuitry of most electrical appliances is made in such a way that it does not matter where to feed L and where N. These are household electric stoves, washing machines, most boilers, etc. In general, this is all the equipment manufactured in the CIS and for the CIS. Such equipment is supplied with unpolarized plugs, which can be inserted into the outlet, as you wish. I came across a technique with polarized forks only if this unit was brought from Europe by someone, and was not bought here. Typically, this is a technique that was picked up by junk collectors in European landfills, repaired and sold here at half price. As for the boilers, the problem here is really the polarity of the inclusion, since the flame control circuit in the electronics board of the boiler is taken not from L and N, but from L and PE. I ran into this, because I have a "triangle", and there’s simply no place to take PE in the apartment, they offered to install an isolation transformer, but I just redid the flame control circuit.

And still, I would like to adhere to a certain uniform standard when installing electrical wiring, and it’s even pleasant to yourself when you know which side the phase is on and which side is zero, maybe someone will have a household appliance for which it matters. Yes, it’s tin with carrying, although at work I recently received a carrying of our RUSSIAN production and was just surprised, really cool as you can say as before with a fivefold power reserve. There were no such stores in our area.

The best solution is to install an RCD together with the DPN (overvoltage sensor) especially in the breech. I have a private sector and then saved 8 times.

And if you use such a scheme? In the floor shield, everything remains as before: three phases, zero, opening switch, counter, opening machine (disconnects the phase during short circuit), wire to the apartment. In the apartment: The voltage controller controls a two-channel contactor, and when the zero breaks “somewhere below” it leads to the disconnection of both zero and phase, saving our devices. Then we divide PEN and put an RCD, connect the device with three wires. Breakdown on the case, leak, etc. lead to the operation of the RCD. By the logic of the devices, we cover all possible standard situations: both zero burning and any leaks. In fact, we took the "UZO outlet" and included the whole apartment in it, and we were safe from the burning of zero before.

I will add that the operation of the voltage controller with the contactor is similar to the fact that in the event of a sudden loss of energy (for example, when zero is burned out), we instantly go to the site and turn off the input switch. And no phase at zero or PE does not wobble us.

At the summer cottage there is a two-wire line. The separate room has a shower and a washing machine. I plan to establish the grounding of this room using the TT system. Question: will RCDs constantly operate in this room with such a grounding system, given the fact that there is some voltage on the washer housing due to the filter?

A week ago, I sent requests to clarify the ban on installing UDT in the TN-C system to the Ministry of Architecture and State Standard of the Republic of Belarus, now I'm waiting for an answer. I consider this ban a complete absurdity. Interestingly, even the candidate of sciences read the scribble on this subject, which was later referred to by an entire EFI laboratory. The main argument (with the calculations) is that if there is an RCD in the TN-C system at the time of leakage through a person, the current will be fatal and not the fact that the RCD will work. Kapets, and if we remove the RCD, then everything will immediately become normal.))) From their words it turns out that a simple machine will protect a person better than an RCD.))) How? Will kill him right away? Exactly the same references are in the Muller and Schneider Electric catalogs. In general, I am waiting for an answer from the drafters of the standards, how will they argue this. And then suddenly we don’t know something, don’t understand.

Sasha,
The RCD responds to a leakage of current in the phase-zero circuit, and the protective conductor has nothing to do with it. The main thing is that there should be enough short-circuit current to the machine body to turn off the machine, if the RCD turns out to be faulty, otherwise it’s a disaster.

andy78, Hello!

I am familiar with these paper traps for a long time! Indeed, all dogs can be hung for one.

Once I had to bring grounding to the 4th floor in one apartment. We made in the courtyard where the beds are the contour of the memory, and then through the basement and pipes of the panel riser they raised the insulated core PV3-1 by 6 mm to that apartment and into the apartment panel. There it means a metal shield in the apartment for 12 modules. There he combined with zero the reduced earth on the grounding bus. Well, the shield body from this bus is grounded the same as all socket lines and lighting lines. The OPS delivered categories D. Well, ASTRO UZO mechanical type A and Iskra-Zes category B automatic machines installed.

What is most important, the electric meter and two-pole input circuit breaker of category C, MARK IEK VA 47-100, remained in the floor plate. at 32A. The trick is that the union of zero with the earth occurred after the passage of this zero through this machine! The trick is that there is a break of this zero to the counter and that machine, then all the neighbors in the riser after this break will all hang on this ground !! And if the current from neighbors' consumers exceeds 32A (which threatens to overvoltage and the dangerous potential to be grounded), then the machine will cut off both phase and zero into this apartment! And then let all the appliances of the lazy and indifferent to the protection of neighbors burn later !!! We tried to make grounding good. 10 two meter stakes were driven in after 2 meters and scalded with an iron ten. But his possibilities are of course limited. I doubt that it would be able to withstand the load from all neighbors in the event of a zero break in a three-phase distribution.This is why I came up with this scheme with a two-pole machine, with the union of zero and earth after it. So I gave my chip to everyone! Now think everything. By the way, I just can’t understand how WHY RE-EARTHING WITH THREE-PHASE DISTRIBUTION IS NOT NORMALIZED BY RESISTANCE! ?? What a madhouse! Not really this abnormality does not threaten anything ????? !!!!

Alexei,
If it were my will, I would put authors and editors of these stupid PUE for the clause of the PUE 1.7.80 !! Still there is no less idiotic paragraph 7.1.78. which does not carry sound instructions and priorities for the use of RCDs of different types !! Honestly, the fifth column from the inside harms Russia!

Not. Honestly this stupid check to scoff !!! After all, I correctly enter these stupid Latin letters and numbers, AND SHE DOESN'T LIKE EVERYTHING EVERYTHING !! Do whatever it is with this muck !!!!! Zadolbala already !!!!

Let them learn to understand the PUE :), and not make claims on misunderstood points. This paragraph refers to a three-phase 4-wire system with the grounding of this 4-wire. A three-phase RCD breaks all 4 wires, together with zero, which is protective in this case. It is forbidden to break the protective conductor in all versions of the PUE. From here follows the second part of this paragraph indicating that the RCD can be applied if the protective zero is taken before (in front of the contacts) the RCD.

So then it is, but RCD can and should be set so that this protective zero is not torn by it. That is, we conduct 3 phases through the RCD, but we do not conduct the zero through it, we just give the RCD a separate conductor to power its terminal N. This is so that the test button works. This option is suitable for protecting 3 phase motors and the lines themselves up to these motors. In this case, if the insulation is violated, the current will flow past the RCD to the zeroed motor housing or to that zero protective core inside the cable. If this cable is damaged. Well, or the current will simply flow not at this zero but simply into the ground. And this also happens often. In ANY THESE CASES, the UZO WILL WORK CORRECTLY! I tried it myself. Unlike the scribe of the PUE, I first experiment, and then I write !! These authors PUE for such moronic flaws need to be driven into the wipers without the right to rehabilitation !! Pure water pests !!! And it’s better to plant them on stakes - so that others don’t have an age !!

But for people like you need stakes sharper and longer! Do you even think about what you write ??! Although you have in this statement, plus the truth that sdes has not yet been mentioned. Namely, the fact that the RCD to everything else mentioned here is also in some cases a fire fighting tool!

You would read, think, and then write! The author correctly writes that there are many fools who refer to the stupid clause of the PUE. And at the expense of outlet RCDs - the author tried to get around the problems in old wiring. When it is impossible to put an RCD at the beginning of the circuit, due to large current leaks, it does not reach the sockets themselves. It just happens in some cases. I had to find leaks under the plaster where the cable insulation was demolished for almost a meter, and then plastered. Naturally, this is not always easy to find, and this search is fraught with dust and dirt due to broken-down plaster. But then it is also necessary to plaster and ennoble it! Here the author offers as an option to install a RCD. Although it is best to try to find and isolate all leaks and protect all lines from the very beginning! And then, after all, electric shock from the walls also beats people and fires from such cases are not excluded.Yes, plus everything else, these are increased electromagnetic fields. The same is not for the good of health.

Yes, really, it's dangerous. Especially if you score one stake and even in the basement, where the soil may not be very wet! Now, if you gag the deep grounding by 15 meters - then it will be grounding and not a parody with one two-meter peg! Or such two-meter need to score at least a dozen, and preferably not in the basement, but from the outside along the foundation. You can combine this business with reinforcement in the foundation and with all kinds of metal structures in the ground. I DO NOT UNDERSTAND! WHAT A FREAK DECIDED HOW NOT TO RENOT THE REPEATED GROUNDING !! In this regard, people do not depict grounding, but pornography !!!

He’s been working for 3 years already and haven’t said any complaints? .... But when the zero breaks off in the three-phase distribution of apartments and houses before your separation, BECAUSE IT IS POSSIBLE TO GENERALLY COMPLAINT ABOUT NOTHING !! God forbid of course! And the author of the article is not so bad - for your information !!! WHAT ARE YOU REALLY RIGHTS, SO THOSE OF THE AUTHORS OF SOME ITEMS OF THE PUE - LONG TIME FOR SOAP !! A PUE FOR THESE REASON IN FURNACE AND IN SARTI. HOW TO SPEAK - DIRECTLY FOR USE! Until the normal edition is released!

You need to think wider and understand that some suggested putting the relay protection against overvoltage before separating the REN conductor. In this case, there really is a chance that the voltage relay will cut off the phase and REN through which a dangerous potential is carried out, which then gets on the case of devices "grounded" in this way in the house. BUT I ARE NOT AN ARCTIC SUPPORTER IN SUCH A WAY! It’s better, of course, to hammer GOOD grounding into the ground! But as one of the extreme possible options - you can also resort to using a voltage relay to prevent the removal of dangerous potential through the REN. But it is precisely this protection that cannot fully guarantee it, since in some cases, when the zero (REN) breaks, the voltage may be normal for some time, AND THERE IS A HAZARDOUS POTENTIAL MAY ALSO APPEAR ON THE TORNED ZERO!

But to resort to such a method of protection against ELECTRIC SHOCK is nevertheless better than stupidly without all to split the REN and use it as grounding even with an RCD - even without !!

Twenty five again !! How many times has this been said here? !! Yes you forget about these moronic points in the PUE !! BETTER THAN EVERYTHING FORGET THESE PUEs (preferably with a hard cover) TO THE AUTHORS OF THESE PUEs IN ONE PLACE !! AND CERTAINLY FLASHING !!!

Oh and wrote a lot. There is nonsense here, which I would have smashed to dust but once !! Take care of this a bit later. Your last conclusion, although it speaks of increasing fire safety, but I do not quite agree with him. UZO saved me and one of my friends in the TNC system !! The shortest and most convincing could teach you a direct and simple way. That is, spoil the nature test. Both would grab onto wires or housings while energized while standing on unpainted metal heating pipes. Only I would have a RCD, but you would not! This is the same thing that I would jump from a plane with a parachute, and you would have no parachute!

I had to see REN conductors 25 mm square cross-section from poor contact! And he saw the same consequences !!

andy78,
They check it narrowly like this: at the end of the work, I take any phase wire in the apartment and touch it with a wet concrete wall (as an option, a freshly plastered wall socket), a small spark runs through and then the Uzo cut-off, the second option is to connect ground to ground, if any. Thanks.

In residential premises, I propose to use the TT system with the mandatory use of RCDs. In this case, protection is guaranteed with direct or indirect contact, but there is no increased danger in the event of a break in the working N-conductor.

To protect against increased voltage when the N-conductor breaks, you can plug in a gas spark gap to operate the circuit breaker.

SP 31-110-2003 "Design and installation of electrical installations of residential and public buildings":

"A.1.7 The use of RCDs for existing housing facilities with two-wire networks, where the electrical receivers do not have protective grounding, is an effective way to increase electrical safety. RCDs when a circuit is closed on the housing in such networks occurs only when a differential current occurs, that is, with direct current touching the case (connection to the "ground"). In accordance with this, the installation of RCDs can be recommended as a temporary measure to increase security until a complete reconstruction is carried out. the decision to install an RCD must be taken in each case after receiving objective data on the state of the wiring and bringing the equipment into good condition.

TN-C network.
Separate the PEN in the shield, N goes to the counter and then does not merge with PEN (although all the meters in the shield are connected with 3 wires input = output = PEN). together with the phase pass through the differential automat. We take the earth from the PEN bus (with a known result at a break of 0 - the phase through the consumers of the neighbors appears on my PE / earth) And here the most interesting ...But what if you take and pass through another diff N from the first diff and the earth at the opposite courses (like). In theory, while there are no consumers, there is no potential difference and the differential is turned on ... At a break of 0, the phase appears on the earth contact and on N (equality) ... but if the device case is accidentally touched under the phase from our formed PE, the potential difference appears on the diff between N and PE. both turn off ... There remains the working phase (if after the previous operation of the ground d-automaton the first does not work) which will certainly work for any leak because N is disabled by the second.
How do you like this ???

Oh yes ... You can’t put a differential on the Pen line ... ((((

Guys, how are you going to include an RCD in TN - C? Can I have a circuit? In our country, what, such problems with literacy or with logic?

If the outlets do not have a grounding contact, this (in the part of such outlets) is not TN-C, but simply "electrical wiring without grounding". Class I electrical appliances cannot be included in such outlets (and it will not work if you do not drill out the sockets or use Chinese adapters). To use such devices, grounding is necessary at least for some system (all provide electrical safety, but to a different extent).

If the instrument housing is wired to a ground bus, which is also tightly connected to N, this is TN-C. No one completely forbade it, it is still used in production facilities. And before, it was even used in medical institutions (perhaps still somewhere else). That is, in normal execution - it is quite safe, but worse than TN- (C) -S. RCDs cannot work with such a system.

If we have separate PE and N lines from the outlet to the shield, and then the general PEN is already a TN-C-S variant. Also widely used. For example, this is how electric stoves are connected in old houses. It should not be used in NEW electrical installations of residential premises (separation should be performed in the ASU), but this does not mean that all those where such a connection will die from "burning zero" :). RCD can be used.

As for the rules, the scope of the PUE is new or reconstructed electrical installations. What to do with a "partial reconstruction" (replacing the apartment wiring, and the riser is old) - it’s not explicitly agreed anywhere. Some professional electricians prefer PE to not connect anywhere, so as not to be responsible. Meanwhile, sockets with an unconnected grounding contact are a direct deception! The user of such wiring, of course, will connect class I devices to them, which is DANGEROUS. Logically, in case of electric shock, the one who installed such outlets will also be responsible. But, perhaps, there is some legal nuance, such as a power outlet, in the consumer’s apartment, and connecting PE to PEN is a common area. In any case, it is a matter of protecting your ass, not the user.

About "burning off zero." Yes, this happens, and with any grounding system. With TN-C or the above-described defective TN-C-S, there is a risk of voltage on "grounded" cases. The magnitude of this voltage depends on the imbalance of the load in phases and only with a strong imbalance it will be dangerous. This situation cannot be overlooked, because in some apartments the voltage will be greatly underestimated, and in another part it will be overstated. This will cause a massive failure of electrical appliances, a fire is possible. Naturally, such an emergency mode will not continue for a long time, the network will be disconnected and the likelihood of electric shock during this accident is quite small in comparison, for example, with an ungrounded washing machine with a phase breakdown in the housing, which can wait a long time for someone to grab at the same time for her and the water pipe. In the latter case, the situation is aggravated by the fact that even serviceable modern electrical appliances have a leak to the case through noise-suppressing capacitors, so those who live without grounding are used to the fact that washers, computers, etc. are always a bit “pinched”.

By the way, even TN-S, made in accordance with all modern rules, does not fully guarantee the inability to get dangerous voltage on the case. For example, somewhere in PE there is a bad contact (they forgot to tighten the terminal). It is almost impossible to detect this while there is no current. But then there is a short circuit to the case, a very large current flows, and in this place PE burns out. And again, nothing is noticeable. Even if the machine has time to work, how many will carefully check the wiring, and not just turn it on again? But it’s all from the area “I won’t fasten my seat belts, turn off the airbag, because I read that someone had broken their ribs or neck with these things.” In most cases, grounding (even "grounding") is still better than its complete absence.

In general, everyone decides for himself, but it is safer to use all means - grounding + RCD + overvoltage relay.

People, but is it possible to put ouzo on a null electric device, for example an electric stove?