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Today’s article is called a potential equalization system.
Many probably heard this name, but not everyone understands what it is, and most importantly, what is it for?
In this article I will tell you in detail what a potential equalization system is, or abbreviated as SUP.
What it is?
In previous articles, we spoke with you from TN-C-S, TN-S grounding systems, where according to the modern requirements of Electrical Installation Code (7th edition) wiring of residential, residential and administrative buildings is prohibited without the use of protective conductors,
Also in the PUE refers to the creation of a potential equalization system (EMS).
Equipotential bonding in homes with a TN-C grounding system is prohibited.
The system of equalization of potentials (EMS) is of 2 types:
- basic potential equalization system
- additional potential equalization system
So what is it?
The SUP is designed to equalize the potential of all conductive parts of the building:
- building elements
- building structure
- engineering networks and communications
- lightning protection systems
The connection is made by PE protective conductors, which are laid separately or may be part of power supply lines. These conductors form the so-called “grid” in the building and must connect all of the above parts with a grounding device and grounding.
In case of damage to the electrical installation and potential (voltage) to the conductive parts of the building, a short-circuit current or large leakage currents occur, which lead to the disconnection of the damaged section of the circuit from the power source, by means of circuit breakers or RCDs.
Basic Potential Equalization System
- ground loop (grounding device)
- main ground bus (GZSH)
- PE Mesh Protective Conductors
- potential equalization conductors
The main earthing bus (GZSH), also known as the PE bus, is installed in the input distribution device (ASU) of the building. For more information about it, you can read in the article the main ground bus (GZSH).
To the main grounding bus (GZSH) connects the steel strip coming from the ground loop (grounding device). It looks something like this:
To the same main ground bus (GZSh) connects:
- PEN-conductor of the input lines (cable) in the grounding system TN-C-S
- PE conductor of the input line (cable) in the grounding system TN-S
Further, PE-conductors of group lines of electrical wiring, as well as PE-conductors of equalizing the potentials of the conductive parts of the building, depart from the main grounding bus.
It is important to know. Basic Potential Equalization System
1. Connection of PE-conductors with N-conductors is prohibited.
Starting from the main grounding bus (GZSH) the connection of protective PE-conductors with zero working N-conductors is prohibited.
2. Connection diagram to grounded structures
The connection scheme to the grounded structures, elements and engineering networks of the building must be radial.
The radial scheme is as follows: each grounded part of the building has its own potential equalization conductor.
Connecting the potential equalization PE conductors by a train is strictly prohibited.
3. Switching devices of protection
It is forbidden to install in the circuits of protective PE-conductors various switching devices of protection. Because the continuity of protective conductors is the most important and basic requirement.
Additional Potential Equalization System
We have dealt with the basic potential equalization system (PCOS). Now let’s look at what is an additional potential equalization system. A DPP system is required to provide additional electrical safety in rooms with increased danger, for example, a bathroom or a shower room.
- equipotential bonding boxes, abbreviated as PMC
- potential equalization conductors
How to make electrical installation of additional potential equalization system (DSPS)?
First of all, it is necessary to determine the installation site of the potential equalization box (PMC).
Next, you need to connect the PE bus of the electrical input panel (apartment, cottage) with the PE bus, located in the potential equalization box (PMC). This is done with copper wire section 6
The third step will be to ground all metal structures in the bathroom:
- cold water supply
- hot water supply
- bath or shower
Protective potential equalization conductors from grounded structures are laid and connected to the PE bus in the potential equalization box (PMC).
Fastening of protective conductors potential equalization to the pipes can be made with metal clamps.
Also, all outlets installed in the bathroom are subject to additional grounding.
The cross section of protective conductors equalization potentials are performed with copper wire with a cross section of 2.5 – 6
After carrying out the electrical installation of the potential equalization system, it is necessary to invite specialists of the electrolaboratory to conduct the following electrical measurements:
- earth resistance measurement
- checking the presence of a circuit between the grounded structures and the grounding bus PE in the box (PMC)
219 comments on “Potential equalization system”
The concept of a system of equalization potentials heard, but now I learned in detail what it is. After such a detailed description of the questions does not remain, everything is clear and simple!
The basic potential equalization system in electrical installations up to 1 kV must interconnect the following conductive parts: 1) zero protective PE or PEN conductor of the supply line in the TN system; 2) the grounding conductor connected to the grounding device of the electrical installation in IT and TT systems; 3) a grounding conductor connected to the re-grounding earthing on the entry to the building (if there is a grounding conductor); 4) metal pipes of communications entering the building: hot and cold water supply, sewage, heating, gas supply and
5) metal parts of the building frame; 6) metal parts of centralized ventilation and air conditioning systems. In the presence of decentralized ventilation and air conditioning systems, metal ducts should be connected to the PE bus of the fan and air conditioners power panels; 7) grounding device of the lightning protection system of the 2nd and 3rd categories; the grounding conductor of the functional (working) grounding, if any, and there are no restrictions on the connection of the network of the working grounding to the grounding device of the protective grounding; 9) metal sheaths of telecommunication cables. Conductive parts entering the building from the outside should be connected as close as possible to the point where they enter the building. To be connected to the main potential equalization system, all specified parts must be connected to the main ground bus with the help of potential equalization system conductors.
PUE 7th edition, Chapter
This is such a “cooking”. Once, it was necessary to observe the discharge of a static charge from the metal roof (S =
From your pictures you can not see the connection of the main system with communications, but only with an additional one.
In a residential building communication project we do not connect to the GZSH.
The electrical riser from which the apartments are fed should be three-phase five-wire. In the PE-conductor in normal mode, no current flows.
With a DSUP device with a four-wire riser, significant equalization currents can flow between the electrical riser and metal pipelines – due to the fact that the PE conductor to the DSUP is taken as a branch from the riser PEN conductor through which the operating current flows. The current through the DPMS can reach tens of amperes, and in case of an accident on the riser – even more.
If the pipelines from the basement do not provide electrical continuity (they have a plastic insert without a metal shunt), then there will be no significant equalization currents, but in this case there is a danger that the dangerous potential will be carried out through the pipelines or in the apartment. Even if a new three-wire line from VRU at home, with a separate PE, is carried out to the apartment, there is one more condition: the main SUP should be performed in the basement of the house.
If that is absent or faulty, then the propelling system in the apartment will have to perform its functions, ceasing to be additional, and becoming the main one without permission and equalizing the potentials for the whole house. The required cross-section of the conductors of the main SUP is much larger than that required for the projection. The main SUP must, without damage, withstand the flow of currents during various accidents on the line, with direct lightning strikes into the building and
This example shows the Verkhovna Rada of a residential apartment building. The electrical wiring of trunk lines was made with 5 wires of the ARC brand with a section of 16
Actually what is the question then? If about DSUP, then feel free to install it on your own in especially dangerous areas, for example, in the bathroom. Who bothers then? And the power supply system (VRU, OSUP) is made according to the NTD.
Why is it forbidden to install a potential equalization system in homes with a TN-C earthing system?
Got a question. My bathroom is grounded to the PMC of the cold-water and hot-water pipes (outlet from the risers to my apartment). At the same time, I am not sure whether the grounding of pipes (risers) in other apartments along my riser (11 floors) was done in the same way. Will I, for this reason, destroy the metal pipes of the cold-water and hot-water supply systems in my riser, since it turns out that the entire grounding of the riser for equalizing the potentials was performed only by me?
It is desirable to connect the risers of the cold-water and hot-water supply to the OSUP. Then there will definitely be no impact on your pipes.
In the past, when designing a propelling system, designers laid a steel strip in the project associated with GSSH in VRU, laid together with pipes (risers), and from it, respectively, threw copper wires into the bath and pipes. Now they are referring to the typical drawing in PUE and forcing to lay a separate copper wire from the fifth core through the whole apartment in the cable channel for grounding baths and pipes. No persuasion to return to the previous version of the DPCS does not help. Sockets in the bathrooms are not provided.
As all the same to be with the PE conductor suitable to the PE contact sockets in the bathroom from the apartment panel … Many authors categorically prohibit to connect it .. In the EIR, it seems to be necessary to connect it … As it’s right …
It is necessary to mount the projection in the picture. But, doubts about the observance of the complex of all measures (given above) are significant. (And here is another tragic message: the guy between the stove and the sink,
Connecting the potential equalization PE conductors by a train is strictly prohibited. And in the PUE in the figure
I asked the question of equalization of potentials in connection with el. corrosion of the heated towel rail (PS). It is connected through metal-plastic. There is an opinion that the PS will have a different potential from the riser, as a result – a current through the water, which leads to corrosion. Recommend copper wire connect the PS and the riser (as well as a bath, faucets). I want to connect the PS and the bath. Is there a danger of defeat email. current with this connection?
Konstantin, there is no danger, provided that the grounding system in the apartment TN-C-S. Ground the towel rail and the bath ground with separate protective copper conductors 2.5-6
Thank! This is all clear. The article really describes everything well. My question is this: what will happen if you just connect the substation, the bathtub, the mixers with the risers of the water supply (without connecting to the ground in the panel)? So they write on the forums where they discuss the problem of corrosion of PS. If this is wrong and, most importantly, dangerous, I will at least give a link to your website so that people will not do business. Thank you in advance.
How is it possible to be with the PE conductor suitable for the PE contact of the socket in the bathroom from the apartment panel … Many authors categorically prohibit to connect it … In the EIR, it seems to be necessary to connect it … How is it right … to connect the PE sockets and RE traffic system together or not?
Tell Dmitry where exactly it is possible to put a potential equalization box (PMC) and what to do if the communication pipes are made of plastic?
It is desirable closer to the communications (pipes, water pipes) that are going to be grounded. If they are made of metal, then they do not need to be grounded. Although this is a very controversial issue, and the inspectors of Energonadzor interpret it differently. For example, I was allowed not to ground them.
Real Grounding For Security does not depend on … interpretations. PE is better (and should be) inseparable.
? Why is it forbidden to install a potential equalization system in homes with a TN-C earthing system? => Sometimes (!) It burns a common N and then … 3 phases … and a queue at the SC. ? How is it right … to connect PE sockets and RE traffic propelling together or not? => Separate conductors, the socket to the PE apartment panel, the DPCS to the PE floor panel (more often it is the floor panel – PE, under different screws). (I understand this; active and passive)? As all the same to be with PE conductor suitable for PE contact sockets in the bathroom from the apartment panel … Many authors categorically prohibit to connect it .. In the EIR, it seems to be necessary to connect it … As it’s right … = => For a washing machine, storage water heater according to the instructions (No grounding through the contact, no warranty) according to the EMP (UZO required!) => For a long time pondered DSUP. You can’t have my TN-C. PE arises from the PEN in the floor shield. It leaves with two wires of 10 mm2 on the shield (inside the apartment, here the terminal block and then separately for each socket block, where there are also plugs (but, you need to solder). Therefore, all protection consists of RCDs, the choice of which must be taken seriously (speed and reliability) And not to fall between the sink and …
There is a complex of paradoxes (as we say). The water in the pipes is not a conductor (power circuits) or, in other cases, a conductor (pro safety). Metal-plastic tubes are not insulators (even if they are dry outside). Grounding is very problematic. Then, if it is correct, you should ground the drain and the faucet (they are exactly metal), the sink, the bath … those according to the EMP.
They also told the following: they made a laboratory installation with an explosive voltage.
Thanks to the author of the site for such valuable information.
And if gas supply pipes have a gap with non-conductive parts inside the apartment several times, then what should be? For example, the gas stove itself has pipes inside it, and if it is connected to a gas pipeline not by a metal braid, is it necessary to connect it with other parts of the SUP?
Do I understand correctly?
Some people from ZHKO came to our house. They had piled up three corners in a flower bed, welded a strip, and put them in a switchboard room. Probably screwed to her neutral.
Then they lifted a strip along the entrance to the top, brought a copper six from each strip into each bathroom, and attached it to each bath.
It’s all. How was the two-wire in the apartments, and left.
And now actually 2 questions.
Do I understand correctly that now there is a heightened danger zone between the boiler, the bathroom and the washing machine, and these people have generally done a bad thing?
Can I now do the three wiring in my apartment myself by planting PE on this our new SUP?
Stanislav, in this case, you first need to switch to the TN-C-S system (three-wire network) with installation in the group lines (especially for the bathroom) of the RCD. A PE conductor for an apartment needs to be taken from the PE main conductor, which should pass through your floors.
This article says that “it is forbidden to make a potential equalization system in houses with a TN-C grounding system. “.
In the article of the same author about the TN-C grounding system it is written that the latter “… is transferred to the TN-C-S grounding system or the TN-S grounding system, by upgrading the power supply circuits. For example, installing a potential equalization system. ”
Well, is it possible or not to do EMS in the TN-C system?
SUP in the TN-C system is prohibited. Soon there will be an article about the zeroing. First you need to transfer the TN-C system to the TN-C-S, and then install the OSUP and DSUP.
Hello! And how to further ground the warm floor? On top of it, it is necessary to mount the grid and ground it from traffic cable or just ground it twice in the installation box of the heated floor?
Nikita, this is what the EMP says about this, p.
Can’t you use a building’s armature as a ground loop?
If the armature is really grounded, then you can.
And how can you check it?
Without experts can not do. It is necessary to check the metal connection of this construction with the “ground”. Contact the Criminal Code to electricians.
Subject raised sharp. Our house was renovated by electricians, and the system was done right. But there is another situation that worries: the pipes of the hot and cold water pipes, as well as the sewers on the risers are replaced with plastic, and the bathrooms are left without grounding (seen several times in different houses). How to be in this situation? After all, with such a replacement, the tire should go along the riser from the GZSH (I saw a new building in the house), and already connect the bathroom to this tire and
I read three times that with the TN-C system it’s impossible to do the SUP, but my boss needs to do the SUP in the kindergarten at the TN-C. To my remark it requires to show a specific place in the EIR where it is indicated on this. Give me something literally — I couldn’t find it myself.
Mikhail, in no case can this be done. Any reconstruction (change) of the electrical installation must be carried out according to the new requirements of the EMP. And in the 7th edition of the EMP it is stated that the TN-C system is prohibited for use (the EMP,
Installation of SUP: (PUE,
Very often in, new homes, all these boxes of DPCS are removed, when reworking
Is it acceptable to use 2 separate grounding devices in the building? Is it necessary to connect GZSH of these chargers for potential equalization? Or is it possible to use them jointly with taking precautions to avoid potential differences? If you combine tires, how can you avoid the risk of running into the same potential difference during maintenance and measurement, when will you have to open the circuit?
Hello, Dmitry! Please answer whether it is necessary in the shower rooms to level the potential, put a metal grid on the floor with a further connection to the ground loop? Then put ceramic tile on the grid.
In PUE 7, in
Alexander, read the EIR,
Maxim, according to PUE, in electrical installations of various purposes and voltages, regardless of the number of IGUs (input switchgear) in a building or structure, should, as a rule, be wired to one common grounding device (charger).
Thank you, Dmitry! I thought so, I was just the word “local” in this paragraph
Hello! I had a question on grounding a towel dryer. If the pipes are made of polypropylene, is it necessary to ground it. And still interested in external aesthetics with the UE system. Just the wires, with a cross-section of 2.5-6, exit from the PM and openly go across the floor to the bath, up to the heated towel rail, to the risers and
Michael, according to Technical Circular No. 23/2009: when using metal-plastic pipes for bathroom equipment, depending on the technology of pipe joints, it is possible to form a continuous conductive circuit formed by pipes and fittings. Conductive elements of the plumbing system: taps, mixers, towel warmers, valves and other parts made of metal, in this case, are considered to be third-party conductive parts to be included in the system of additional potential equalization.
Choose yourself, or aesthetics or electrical safety, although if you try, you can hide the wires to the maximum.
Hello, if the mounted system TT all the rules and soil-clay. I have to invite the inspector for measurements.
A novel, if the technical conditions for the mandatory measurement of a grounding device (charger) do not say anything, then the resistance of the charger can not be measured, but note that this will be on your conscience if the RCD in the TT system does not work, because it is the main protection against touch to live parts. I recommend reading the article about the requirements for the TT system.
I did not understand about the radial system and the train. How to understand. More in detail. Thank!
“All the sockets installed in the bathroom are also subject to additional grounding.” I didn’t quite understand, that is, do I need to pull 2 ground wires to the outlet? one in the power cable, the other from DSUP?
One is enough, either with the power cable, or from the box of the PMC.
Hello. I have a new house, the land is in the panel in the apartment and goes to each outlet, they stand in the panel.
Alexander, connect the body of the bath to the PE-conductor (“earth”), which is wound up in a shield.
Admin please tell me how to deal with the equalization potential in the grounding system TT. Which of the grounding connect the potential equalization circuit? What is the difference between simple grounding of current-carrying parts of electrical devices and potential equalization?
Alexey, in the TT system there is one grounding device, so connect it to the SUP.
Hello! I read the notes about grounding, SUPs, etc. I will briefly describe the situation. At school, the grounding system was and is TN-C. At the moment, the reconstruction of the catering unit. The input is mounted by SIP. In the shield a separate shield on the school, separate on the nutrition unit. From the counter to the dining room is a four-wire cable. Can I separately install the TN-S or TN-C-S system in the food block, make the EMS? Grounding in the food unit is available. And advise, please, how to do it all. Thanks in advance.
Is it possible (necessary) to connect the third protective contact of the socket at the same time to the DSUP and to the PE conductor coming from the shield to this outlet? and how to connect in this case the water heater? Corps on a DPMS in the PMC? or body to the third protective conductor PE coming from the shield?
Roma, for the earthing contact of the outlet is enough of something one, or connect it from the power cable, or a separate conductor from the PMC.
Please specify how you additionally (MANDATORY.) Have grounded your outlet in the bathroom (according to the last paragraphs of the SUP article).
Additionally, it is not necessary to ground it. One grounding from the power cable is enough.
Thank you, interesting article. But I have a question about equalizing the potentials in networks with voltage over 1 kV. For some reason, when considering the topic of equalization of potentials, an emphasis is placed on networks up to 1kV. It is clear that there is no fundamental difference, but I wanted to clarify the situation regarding the need for GZSH, since following the PUE it is used only in networks up to 1kV. Share your thoughts))
And if gas supply pipes have a gap with non-conductive parts inside the apartment several times, then what should be? For example, the gas stove itself has pipes inside it, and if it is connected to a gas pipeline not by a metal braid, is it necessary to connect it with other parts of the SUP?
Metal braid is strictly prohibited item.
I have a question about DSUP in the bathroom.
The article says “sockets in the bathroom are subject to additional grounding.” As I understand it, they are connected to the apartment’s RE-bus and to the bus in the PMC. It turns out the ring connection, as through the socket the apartment PE-bus is connected to the PE-bus in the PMC, and from there to itself. How permissible is this?
Or am I so stupidly epic?
If there is no OSUP, is it allowed to connect the DSUP?
Good day. I want to ask, something I can not understand what is my grounding. Entering into the house is single-phase, he made the grounding himself, he pushed three pins into the ground. Tell me please.
Good afternoon. If you make a DSUP in a bathroom of reinforced concrete, then you probably need to somehow connect the concrete fittings to PE? This is in case of a broken PEN conductor between floors. If PE is taken on the floor plate. And after all, reinforced concrete floor refers to the factors of increased danger.
Tar60, if you have zero and PE are not interconnected, then this is a TT system, and if there is a jumper, then TN-C-S.
Hello. I want to ask. We have a major overhaul in the apartment – replacing wiring, pipes in the bathroom (with polypropylene) and replacing the bath itself with a cast-iron one. The question arose whether to ground the bath. Our master did not plan to ground it at all, but after my request I made the grounding in this way: I attached a three-core wire in the bath leg (all three of its wires), and he plans to unite the second part of it with the third wire which is the “ground” in the wire to which the boiler will be connected. Is this grounding correct? Do not kill all the current?
Tatyana! If you have a complete replacement in your apartment
Is photo of the Shield in the photo №3 showing the GZSH from aluminum?
Dear Dmitry! Thank you for such a useful resource where you can get information on electrics … Please help with the choice of solutions from this situation. Apartment house. TN-C grounding system. Electrical flat wiring is made with two-wire cable. Connecting a washing machine (CM) and dishwasher (PMM) machine, also a two-wire cable.
When the indicator screwdriver touches the SM and PMM cases, the neon lamp on it glows. The water distribution in the apartment is made with metal pipes, the counters of hot and cold water are connected through metal-plastic pipes. When taking a shower, there is a “tingling” of electric current.
The measured voltage between the SMM housing and the metal water pipes at the entrance of the apartment is 60 volts, the current flowing through this section is 3 mA. (RCD does not disconnect the circuit)
When using the potential equalization circuit (SMM, PM and baths and all (input and internal) water pipes, the current does not beat. But the PMC cannot be used,
Hello, help me figure out how to do everything according to your mind. The problem almost coincides with the problem of Yuri, only I have polypropylene pipes and a bus bar next to me for grounding. He himself spent about 5 years ago metal wire for grounding sockets in the apartment, but he connected it to the main inter-apartment panel (when he connected the spark a little bit), now I understand a little that I didn’t do it right, I just wanted to know whether I was right or not. And you can use, as the land for the apartment, the bus, which the workers held when installing the pipes? UZO is not installed, there is an old meter and 2 machines for 25 A. I wanted to completely change the wiring in the apartment, now there is an aluminum one, and without grounding there is a problem at all. Thanks in advance for your reply.
Hello! In the adjacent object with a steel sink there is a dishwasher, is it necessary in this case to ground the sink and, if so, is it possible to manage the dishwasher outlet ground so as not to pull a separate wire from the dashboard? Thank you in advance.
It is possible only for protection it will be necessary to install a difavtomat or RCD
Thanks for the article, everything is clearly shown. But the question arose, do the showers in the locker room for the hockey team. Is it necessary to lay a grid on the floor in the shower room itself? What material? What step?
Dmitry, hello. Is there a risk of electric shock when touching, for example, radiators or a faucet during a thunderstorm (at the moment when the lightning passed through the lightning protection system of a private house) if the SUP system is installed according to all the rules (considering that the grounding of the lightning protection and the grounding circuit should houses be interconnected)?
Anton, to your question: is it possible to use the fixtures in the house and how to check it – the answer is: take the control lamp for 220 volts and at least 100 watts and connect one control wire to the phase of your apartment, and the other to the home fixture. If the light bulb is fully heated, then this ground is excellent. If there is no such lamp, then it can be connected in this way. A 1000 watt iron is working normally, so everything is fine. grounding is very good, you can use it. if the light bulb is barely lit, then grounding is weak – it is not suitable for work. Look for another ground.
And how to find the phase in the electrical outlet, then it is necessary to probe the voltage indicator with both holes in the outlet, in the hole where the indicator is lit, there is a “phase”. It is possible and a light bulb – one wire from the light bulb to connect to ground, and the other to insert alternately in both holes of the outlet in your apartment, and where the light is on, there is a phase. Check the ground together and where is your phase. Good luck to you, just follow the safety instructions. Bulb carefully isolate and all connections are well wound insulating. The edges of the wires (probes), take it carefully, do not take bare ends with bare hands. There is a high voltage – 220 volts, life-threatening.
Tell me please, there is a mobile base station with a radar in which there is a bus that connects with a wire with a cable that hangs on the wall of the room. The headphone connects all stationary equipment, and the re ppc bus connects the protective conductors of sockets and air conditioners. The question is where is SOUP and where is DUP?
Dima, tell me, do you have an article on how to read electrical circuits correctly? Such, for example, as the top scheme. Searched your site, did not find.
Is it possible, or it may be necessary, to connect a concrete floor in the bathroom to the DSUP? Just now at the repair stage there is access to these fixtures. In theory, because it will not be worse?
Dear administrator., Tell me, from KUP, to a block of 3 sockets, you need to drive, 3 wires, or will it be correct to make jumpers?
Hello. In which systems TN-S, IT, TN-C, TN-C-S, TT, can a potential equalization system be made, and in which systems is it not?
Can you please tell me, is the metal floor of the room (boiler room), connected by welding to the metal frame, the bus I LIE and to the ground loop, can it be used as an SUP bus or do you still need to drive a separate strip along the inner perimeter? The second question – if the electrical equipment with its metal base is installed on this metal floor and is additionally welded to it, is it still necessary to separately connect this equipment with a separate visible conductor to the metal floor?
Oleg: 1. In paragraph
Good day! In my opinion you have a mistake. In the third figure in a row, it is shown that the PEN conductor was mounted on the N bus on the input cable. From your article, I understand that the PEN conductor is screwed to the PE bus.
Dmitry, please tell me, what is the minimum cross-section that a grounding lead from a 18 kW bolter should have, if the cross-section of the power cable is 3×6 + 1×4 mm2?
Well well. It seems that everyone around them has completely forgotten that the TN system (no matter, -C, -C-S, or -S) requires mandatory ZANULATION (
Or rather not “PE or PEN”, but “N or PEN”
Victor, then a question for you as an advanced electrician:
Please tell me, what is the minimum cross-section that should have an earthing lead from a boller of 18 kW, if the cross-section of the power cable is 3×6 + 1×4 mm2?
Nikolai, good day. PE conductor must be at least 6
Victor: “… Or rather, not“ PE or PEN ”, but“ N or PEN ””
Wrong. “N” is never used for this purpose. Only “PE” at TN-S or “PEN” at TN-C.
I never wrote that in the TN-C system there is a conductor “PE”. In the TN-C system there is a conductor “PEN”. Metal structures are connected to it. (cm.
2. In the TN-C system there is no “N” conductor, but there is also no PE conductor. 3. Why there is no your comment about single-phase two-wire systems, do you think we have a second PE or N wire? 4. For automatic shutdown, you must have a PE conductor, as well as N conductor, depending on the power supply system. 5. Answer why we measure current.
1. Automatic shutdown for leakage current (RCD) does not apply to any of the TT, IT, TN systems and does not determine what the system is. The physical possibility or impossibility of such a shutdown also does not determine which system it is. 2. A strange point … I after all wrote that TN-C has PEN, but no N and PE … 3. In single-phase two-wire systems, if you need to realize TN, one wire is L (phase), the other is PEN (combined zero work and zero protective). (If there is a zero conductor at all. In other cases it may be a PEL or PEM conductor.) 4-5. The resistance of the “phase-zero” loop is measured in order to make sure that in case of a short circuit IN THE LOAD CHAIN the protection will work (an automatic shutdown will occur). This does not apply to TT, IT or TN. Loop resistance must be measured in any system. In a TN system, an automatic shutdown should occur in case of a short to metallic conductive parts. This is solved by connecting these same parts to the zero point with a PEN or PE conductor. By the loop “phase-zero” is irrelevant. 6. The PE protective conductor “zero” was born at the time of the invention of the TN system. Together with zero worker N and combined PEN. Neither before nor later. These are components of one system. The presence or absence of a RCD, actuation or failure of the RCD does not determine TN, TT, or IT and does not relate to “zeroing” …
Admin: Please join the discussion on this topic, since this is one of the very important and interesting topics in the electrics section after the introduction of the OLC 7, I consider such topics should be discussed first. People do not understand how to figure out and what to do with these most common single-phase two-wire networks in the old housing stock mounted in accordance with EIR 6 (Ch.
1. Consider the item you have mentioned the following code:
2. You write: “… I consider grounding primary. If there is no grounding, how will you organize a deaf-grounded neutral … “My comment from
3. You write: “… to ensure the full operation of the automatic shutdown, the TN-C system is not suitable in certain cases, it will not work when the phase closes to zero …” That matter is not at all in the organization of the grounding or grounding system. Even when designing, the source power, conductor cross section, circuit breaker tripping currents, insert melting currents and type of fuses and
4. ПТЭЭП Annex 3