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Corrugated pipe for electrical wiring

 


What is a corrugated pipe?

Corrugated pipe for electrical wiringOne of the simplest, but at the same time brilliant inventions of mankind is a corrugated pipe (corrugated pipe). Why is she so wonderful?


Corrugated pipe - this pipe with a variable cross-section. Short sections with thin walls and a small diameter are interspersed in it by sections with thicker walls and a large diameter. At the same time, thick-walled sections give the pipe rigidity in the transverse direction and the ability to withstand impacts and loads, while thin-walled sections allow the pipe to bend at almost any angle and even stretch within limits depending on the type and total length of the pipe.

The corrugated pipe can be metal, but most often it is made of plastic. The flexibility and durability of the corrugated pipe predetermined its widespread use: it is used both in the ducts of ventilation and exhaust systems, and in plumbing to connect drain siphons to sewers, and in air conditioners for condensate drainage. And for the installation of cable lines for electrical wiring and various other networks used special electrical corrugated pipe (corrugation) made of PVC.

Advantages and disadvantages of corrugated plastic pipes

Pros:

  • it is convenient to apply when laying on uneven surfaces and with turns;

  • fireproof;

  • protect the cable from mechanical damage and high humidity;

  • protect people from electric shock.

Minuses:

  • it easily bursts and breaks in the cold, so for outdoor applications it is better to purchase corrugated metal pipes.


Structural features of an electrical corrugated pipe

Structural features of an electrical corrugated pipeIf you cut the electrical corrugation along, you can make sure that its profile is rectangular. Polyvinyl chloride is a fairly tough material, and the length of small diameter sections of an electrotechnical corrugation is not very large, so it is not stretched as much as many other types of corrugated pipes. But its flexibility is literally on top, especially for corrugations of small diameter.

The main distinguishing feature of the electrotechnical corrugation is the presence in the internal cavity of the broach - a thin steel wire designed to tighten the bundles into the pipe. The color of the corrugation for wires is usually gray in various shades, but foreign corrugation can be blue, red, and, possibly, some other colors.

When purchasing an electrical corrugation, it is necessary to take into account the fact that the diameter given in the catalog is external. It differs from the inner diameter intended for placement of wires by at least several millimeters upwards. Therefore, it is very easy to be deceived by calculating the total diameter of the wire harness and choosing, without looking, a corrugation of the same diameter.

In general, the running diameters of the corrugation for wires vary from 16 to 50 millimeters. Less often you can get a pipe of a smaller or larger diameter. The construction length of the corrugation bays depends on the diameter. So the corrugation with a diameter of 16 mm is supplied in bays of one hundred meters long, and the length of the corrugation bay with a diameter of 50 mm is only 20 meters.


Installation of wiring in a corrugated pipe

Installation of wiring in a corrugated pipeDue to the fact that for the manufacture electrical corrugation Since PVC is not burning and does not emit caustic smoke, the wiring in the corrugation can be mounted on any building structures, including wooden ones. Often corrugation is also used for mounting wiring for cladding in wooden houses, although smooth rigid pipes are strongly recommended by the rules in this case.

Installation of wiring in the corrugated pipe begins with the determination of the required length of the corrugation. Then the necessary piece of pipe is cut with a knife. Steel broach is eaten by side cutters, and here it is very important not to “miss” the broach, not to let it go inside the pipe.This can happen due to the fact that the wire inside the corrugation always has some stretch. Having gone inside, she will rest against the pipe with a rigid end, and it will be possible to get it only by making a new incision in another place. In order not to get into such an unpleasant situation, the broach should be held with your fingers during a snack, and after that it should be pulled out a little and bent along the pipe.

The wiring harness to be installed in the pipe must be prepared, fastened with electrical tape along the entire length at regular intervals. It is better to use electrical tape not cotton, but PVC, since the latter is smoother and does not create excess friction.

The end of the harness, which will be pulled into the corrugation, must be securely connected to the broach. Electricians do it differently. Someone simply wraps a harness around with steel wire, squeezing and pulling it with pliers. And someone considers it necessary to puncture several times with a broach the outer insulation of the bundle cables for a more efficient connection. In any case, the resulting structure is tightly wrapped with electrical tape so that the ends of the cables do not stick out to the sides and do not abut the bends of the corrugation. The longer the junction of the broach and the harness will be, the more reliable it will be. Therefore, saving is not recommended.

corrugated pipe (corrugated pipe)After preparing the harness and connecting it with a broach, it is necessary to proceed to the most crucial part: tightening the harness into the corrugation. This job is easier to do together. One person holds the broach tight, and the other pulls the corrugation on top of the tourniquet. You can cope alone if you securely fix the broach, for example, winding it to some element of building structures. In any case, it is desirable to have free space for stretching the corrugation and strong hands, capable of pulling the corrugation monotonously and with great effort.

If the connection of the broach and the harness was not reliable enough, or the harness was pulled through a sharp bend, the broach can come off and fly out of the pipe. In this case, you will have to cut the corrugation and make it from pieces, connecting them with electrical tape. Such a scenario, of course, is simply undesirable, therefore it is better to observe extreme caution throughout the work with corrugation and tow.

After the harness is tightened, the corrugated pipe is attached to the wall or ceiling. For fastening, you can use an aluminum mounting strip or special plastic clips that are selected according to the diameter of the pipe and sold individually. Fasteners are located on structures at approximately equal intervals to avoid sagging of the corrugation, which has a tangible weight due to the presence of a harness inside.

When connecting sockets and switches, as well as when entering harnesses in junction boxes, it is better to hide the end of the corrugation inside, so that there are no bare cable sections. For this purpose, sockets, switches and boxes with rubber sealing devices cut to the corrugation diameter are purchased. The latter is especially true for outdoor wiring.

Despite the fact that the appearance of the wiring in the corrugated pipe is not considered particularly demanding, in the presence of skill and experience, its installation can be done quite accurately. At the same time, for such premises as, for example, a country house, or a summer cottage, the device of such wiring will be a practical solution that will save a lot of money.

Alexander Molokov

See also at i.electricianexp.com:

  • Errors in wiring in corrugation
  • How to do the exhaust gas generator yourself
  • Pipes for electrical wiring
  • Laying the cable through the air in the country
  • Installation of open wiring in the home

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    Comments:

    # 1 wrote: | [quote]

     
     
    Comments:

    # 2 wrote: | [quote]

     
     

    Not understood. But is PVC not polyvinyl chloride? Under the sheathing in wooden houses, I still advise not a corrugation, but a full-fledged pipe.

     
    Comments:

    # 3 wrote: | [quote]

     
     

    PUE, seventh edition, 7.1.38.Electric networks laid behind impassable suspended ceilings and in partitions are considered as hidden electrical wiring and should be performed; behind ceilings and in the voids of partitions made of combustible materials in metal pipes with localization ability, and in metal blind boxes; behind ceilings and partitions of non-combustible materials * - in pipes and ducts made of non-combustible materials, as well as cables that do not spread combustion. In this case, it must be possible to replace wires and cables.

    PVC pipe does not have the localization ability and can not withstand a short circuit in a cable or wire without burning out the walls.

    Understand the purpose of this PVC pipe. And here is the electrical wiring, if this pipe does not have localization ability. Only lazy people and lobsters can carry out hidden wiring on combustible substrates using PVC pipes and corrugations, in the hope of cutting down the loot and rushing away. And the customer then swells, it is good if he survives after a fire due to a short circuit. The use of PVC pipes and corrugations in a hidden electrical wiring on combustible substrates is also the same as wrapping the cable with cellophane and laying it hidden.

    SP31-110-2003
    14.15 Electrical wiring in cavities above impassable suspended ceilings and inside prefabricated partitions are considered as hidden, and they should be performed:
    - behind suspended ceilings and in the voids of partitions made of non-combustible materials of NG and the G1 combustibility group, conduct electrical wiring with wires and / or cables in non-metallic pipes that meet the fire safety requirements and non-metal ducts, as well as cables with the ng-LS index (not spreading combustion , with low smoke and gas emission);
    - behind suspended ceilings and in the voids of partitions made using materials of the G2 combustibility group, conduct electrical wiring with wires and / or cables in metal pipes and metal boxes with a degree of protection of at least IP4X;
    - behind suspended ceilings and in the voids of partitions made using materials of the G3 combustibility group, carry out electrical wiring with a cable in metal pipes and metal boxes with a degree of protection of at least IP4X;
    - behind suspended ceilings and in the voids of partitions made using materials of the G4 combustibility group, conduct electrical wiring with wires and / or cables in metal pipes with localization ability, as well as in metal deaf boxes with localization ability;
    - electrical wiring must be replaceable.
    Localization ability is the ability of a steel pipe to withstand a short circuit in the wiring laid in it, without burning its walls.

     
    Comments:

    # 4 wrote: Author | [quote]

     
     

    Corrugation for hidden wiring on combustible structures should not be used - I do not argue or deny it. The best and correct option recommended by the PUE is a grounded metal pipe.

     
    Comments:

    # 5 wrote: | [quote]

     
     

    Well, you, my dear, again write articles contrary to the PUE. After all, a stingy reader will do everything according to your advice, buy a cheap PVC corrugation, and make himself a fire hazardous electrical wiring. You need to be more responsible about the texts, you should not give such advice. I understand that you also want to eat, so you promote the site by collecting more and more public on it, and then post paid posts with advertisements (for example, how to repair a microwave with your own hands, or the courses of Mr. Vanyushchin), that's okay, that's all they do that. But here conscious bloggers (for example, like Sergei Dolya and many others) never give advertisements that can harm people, and write only about what they are 100% versed in. And you give advice, I'm sorry, as an amateur. Recently, the State Duma was discussing a law on the placement of harmful information on the Internet of pornographic content, which should not be accessible to children.In my opinion, sites like yours carry almost the same threat. If someone will post on your advice, where is the guarantee that he will be alive after that? And the worst thing is that anyone can advise, without understanding the essence of things, now, and anything, and as always, there will be nothing for anyone (((.
    A big request, if you do not understand something, do not consider these topics at all and do not write anything about it. Do a better review of all sorts of new products, you do it very well, I personally like such articles. But please do not give advice and do not consider topics related to a good knowledge of regulatory documentation.

     
    Comments:

    # 6 wrote: andy78 | [quote]

     
     

    Zhora, the author of the article "Corrugated Pipe for Wiring" (Alexander Molokov) has nothing to do with the placement of "paid posts with advertising" on the website. I do all the work on the selection and placement of content on the site, and naturally, I am responsible for the quality of the information posted on the site.

    By the way, do you remember that you wrote about being sent abroad for electrical wiring without a specialized education, a license, etc.? So, yesterday I read one good Western book about the design of lighting in the garden. It was written for gardeners, not for electricians. And there, the author (Peter Hagen) recommends gardeners to choose and lay cables, install control devices and street lamps on their own, as he said "this work is unlikely to be difficult for most gardeners." In extreme cases, it is recommended to consult with the seller of electrical goods in the store. According to Hagen, a specialist should only connect the cable to the shield and to the lamp itself. According to your words, it turns out that all the unfortunate gardeners who made electrical wiring in their garden according to this book should definitely be planted there.

    As for the article, yes there are always controversial issues and they can be found in any topic covered. Not for nothing in electrical forums about seemingly simple questions whole discussions are going on. Alexander wrote an article, you corrected it at some points, he agreed. What's so bad? In my opinion, an article about corrugated pipes for most site visitors will be very useful. Naturally, your addition to it makes it even better. I will be glad if you continue to criticize the materials on the site in the case. Desirable, with links to regulatory and technical documentation.

     
    Comments:

    # 7 wrote: Vladimir | [quote]

     
     

    Regarding the use of PVC corrugation in wooden houses is definitely not there, it should be used only for laying on a non-combustible or non-combustible base. Regarding combustion, we don’t suck it right, the same DKC writes on its PVC pipes not spreading combustion, so everything should be fine on the same concrete or brick wall.

     
    Comments:

    # 8 wrote: | [quote]

     
     

    About books and sellers, I do not agree with you. In my opinion, you need to trust only GOSTs and literature of the Soviet edition. Now books are published by all and sundry. And it’s not worth talking about sellers in the store. Their task is to sell their Chinese goods as expensive as possible, and electric and fire hazard are their last concern, the advisers from them are useless.

     
    Comments:

    # 9 wrote: Author | [quote]

     
     

    But where do I recommend hidden wiring in wooden houses to perform in the corrugation? Well really?

    Something I am obscurely speaking, it seems. Yes, this is often done - this is a fact; you won’t argue with that. But I did not say that it was right.

     
    Comments:

    # 10 wrote: Vladimir | [quote]

     
     

    Auto RU. In my opinion, the article is written.
    Due to the fact that for the manufacture of electrical corrugation, non-burning and non-corrosive smoke-emitting polyvinyl chloride is used, the wiring in the corrugation can be mounted on any building structures, including wooden ones.
    And even on smooth PVC pipes, it is written on some that it is only fireproof or difficult to burn, then write more precisely so that everyone understands.
    Zhora, about books I sometimes agree sometimes they write such bullshit that the hair is on end, but about sellers it’s another question which seller, if he speaks and confirms with certificates, why not, especially if you remember that insulation is made from the same PVC for cable including VVGngLSLS, so it’s a banal truth to buy high-quality and not to save on your safety and on someone else’s.

    So I used corrugation only openly and only on concrete or brick walls, otherwise you never know what, and according to the standards if you can explain everything. But hidden or on combustible surfaces, this tin is in the end one or two defective machines and a fire is ensured, no matter how good and branded corrugation it is designed for such bullying.

     
    Comments:

    # 11 wrote: Author | [quote]

     
     

    For combustible structures, lay the cable in the corrugation CAN. But only OPEN.

     
    Comments:

    # 12 wrote: | [quote]

     
     

    Quote: Author
    On combustible structures

    Then give a link to the regulatory document in support of your words.

     
    Comments:

    # 13 wrote: Vladimir | [quote]

     
     

    I support Zhora a link to a regulatory document in the studio. I rummaged around in the DKC catalog and found a rigid smooth PVC pipe series 6UF, it can be written on it openly for any combustibility category, but somehow it does not fight against the standards. But on the corrugation only non-combustible or non-combustible base.

     
    Comments:

    # 14 wrote: Author | [quote]

     
     

    You are welcome:

    PUE p.

    2.1.37 - “With the open laying of protected wires (cables) with sheaths of combustible materials and unprotected wires, the clear distance from the wire (cable) to the surface of bases, structures, parts from combustible materials should be at least 10 mm. If it is not possible to provide the specified distance, the wire (cable) should be separated from the surface by a layer of non-combustible material protruding from each side of the wire (cable) by at least 10 mm

    You are really addicted to security. Of course, it is better to play it safe again, but according to your logic, a plastic box in wooden houses should not be used. He, too, can burn out in the event of a short circuit.

     
    Comments:

    # 15 wrote: | [quote]

     
     

    Well, where does this fad come from? It says that if you lay a cable with a combustible sheath, for example, on a wooden wall, then the distance from the wall to the cable must be protected with a layer of non-combustible material (such as asbestos). If you really want to lay the cable in the corrugation, then in any case you have to put a layer of fireproof material according to clause 2.1.37, then there will be no contradictions. And if you just lay the cable in the corrugation along the wooden base, then paragraph 2.1.37 will be violated.

     
    Comments:

    # 16 wrote: Author | [quote]

     
     

    It’s hard to communicate with you. It is precisely at the point that when using a cable with insulation of NG and LS it is enough to provide either an air gap or a layer of non-combustible material. Or both. Corrugation is quite suitable, not necessarily asbestos, which, incidentally, cannot be used in residential premises. Because it is unsafe for health.

     
    Comments:

    # 17 wrote: | [quote]

     
     

    "You're really addicted to security." - Well, you give my friend !!! Why do deliberately dangerous electrical wiring? It's one thing when you do wiring for yourself. Then of course, you are your own boss, in which case you yourself will be to blame. Another thing is when you do this wiring to someone else. Who will be to blame in this case? As a rule, everyone is trying to save money and asking some local "specialist" to quickly make wiring. Such a specialist will not bother with security, will buy cheap corrugations and make quick installation, cut down money and look for it later. And then someone will live like on a powder keg with such electrical wiring.

     
    Comments:

    # 18 wrote: Author | [quote]

     
     

    Security cannot and should not be 100 percent. This is from industrial safety theory, if you're interested.

    Upon reaching a certain percentage of security, its further improvement becomes meaningless.

    Say, in our example, if the installation is performed on wooden structures in the corrugation, then the risk of fire, for example, is 0.03%. Putting asbestos under the corrugation, we get 0.01%. (everything is conditional, of course). Are costs commensurate with a change in security? I think no. And the theory confirms this.

    Open wiring in a corrugation on a tree is not prohibited by the PUE, which means it is allowed. When using quality and certified cable products, of course.

    And again, if I were wrong, then in a plastic box it would be impossible to pull the wiring through the tree. There are no fundamental differences. Both there and there - plastic. And in the boxes most often wiring in wooden houses and mounted. Less often - on metal strips, or on a sketch of plaster. Corrugation is rarely used only because it is not very beautiful.

     
    Comments:

    # 19 wrote: Vladimir | [quote]

     
     

    Author, in the PUE a fireproof base is written, but is it a PVC pipe? Again, I crawled through the catalogs so unloved by Zhora and all the corrugation that I dug (PVC) only on the basis of non-combustible or difficult to combust material))) does not beat with your statement. A definition of fireproof material is needed, and something on the pipe says that it is fireproof, and so it only does not spread combustion.

     
    Comments:

    # 20 wrote: Author | [quote]

     
     

    That is, you want evidence from me that the corrugated pipe can be considered fireproof? I will look in this regard for evidence at my leisure.

    Although the fact of the emergence of discussions on this topic suggests that a lot of things are not written in the rules. For me, nevertheless, the starting point for the interpretation of paragraph 2.1.37 was the unambiguous admissibility of installing a plastic cable channel in a tree that any inspection misses. Since it is possible with him, it means, in accordance with the same paragraph, and corrugation is allowed. Because there is no direct prohibition.

     
    Comments:

    # 21 wrote: | [quote]

     
     
    Comments:

    # 22 wrote: Author | [quote]

     
     

    Again, they suspect me that I suggest using any cable. What kind of misfortune is this? Not SL, by the way, but LS. Well, it goes without saying in a wooden house, after all.

     
    Comments:

    # 23 wrote: Vladimir | [quote]

     
     

    Author,
    look, you can find, I honestly also rummage, since on the one hand the corrugation in the manufacturer's recommendations goes only to a non-combustible and non-combustible base, and a smooth pipe (of the same production) is already to the base of any combustibility class, which is strange as there and there PVC . At leisure, I will look at TU and GOSTs that are prescribed for them, maybe there is something interesting there.

     
    Comments:

    # 24 wrote: Author | [quote]

     
     

    Vladimir, it’s very nice, of course, that we so quietly switched to “you”. I’ll try to search - for me, truth is more important than my own authority and ambition.

     
    Comments:

    # 25 wrote: | [quote]

     
     

    Quote: Author
    Again, they suspect me that I suggest using any cable. What kind of misfortune is this? Not SL, by the way, but LS. Well, it goes without saying in a wooden house, after all.

    Thanks for the amendment! As practice shows, the corrugation and PVC pipe is usually used for concealed laying on fireproof substrates to ensure the interchangeability of electrical wiring. And also when laying the cable on the outer walls on fireproof bases. In this case, the use of corrugations and PVC pipes is reasonable and installation is much easier and cheaper, and there are also no contradictions with the PUE.

     
    Comments:

    # 26 wrote: Vladimir | [quote]

     
     

    I apologize for switching to "you", but this topic is also interesting to me since I am engaged in the design of power supply, including internal, and I would not want to have objects burned up due to incorrect technical decisions, and I’m not willing to substitute hyphens, and all the more people in this building to drive into the other world in groups of many people at a time))) Therefore, I always drove VVGngLS and metal without corrugation, it is only in concrete (I’m silent about the installers here).

     
    Comments:

    # 27 wrote: | [quote]

     
     
    Comments:

    # 28 wrote: | [quote]

     
     

    .

     
    Comments:

    # 29 wrote: Vladimir | [quote]

     
     

    Zhora,
    coordinates scribbled see mail. Regarding PVC, the corrugation is in accordance with the standard of air safety standard 246-97, but the rigid pipe is GOST R 53313-2009 (source catalog DKS).Now I read the test methods described in them.

     
    Comments:

    # 30 wrote: Author | [quote]

     
     

    So, what I want to say on a topic that has remained unclosed.

    The rules of PUE, as practice shows, regarding the issue are somewhat vague and are interpreted by different electricians in different ways. I dare to speak on this subject to the developers of the rules: in terms of plastic pipes, it was necessary to speak more clearly. Maybe there are some other norms or circulars, unknown to me, in which clarity is introduced into the question. If anyone knows - please unsubscribe.

    On the other hand, indeed, many manufacturers of PVC corrugations make a mark on the part of the scope: "for open installation on fireproof and fireproof structures."

    Therefore, for mounting corrugations on wooden walls, it is better to use special clipsproviding a gap between the cable and the wall of just 10 mm or more, which already clearly enters into agreement with clause 2.1.37 of the PUE.

    I still think that the main danger of laying corrugations on wooden walls with ordinary brackets is that the excessively picky inspector can "screw up" your object, and you won’t be able to give unambiguous arguments in your favor. Therefore, only clips.

    Good luck to everyone, and many thanks to my tireless critics.

     
    Comments:

    # 31 wrote: Dmitriy | [quote]

     
     

    Trying to logically think about this topic. He took the corrugation into his hands, tried to set it on fire - it does not burn without an open flame. In the army, the battalion commander laid the whole bath in it under the lining. The bathhouse burned down (I’ll say right away not because of the wiring). I’m wondering what happened to the wiring. It turned out that in those places where the temperature was the highest, but without an open flame, this corrugation contracted and wrapped the cable (VVG cable, I don’t remember with or without ng), thereby the fire did not touch the wiring at all. The only shorty was in the fixtures, where the insulation on the cores simply melted and passed through the body of this lamp itself. But in this case, an automatic machine worked for me. This is one point. The second, opened the first price list on galvanized electrical pipes. The most popular 16, 20, 25. Their price is 110 rubles, 135, 197 for three meters, respectively. The price of corrugation for internal laying (for the same 3 meters): 15, 20, 25 rubles. Third, based on logic: the weak point in the wiring is its connection. Why do I have to take the whole cable and shorten it (if there is a switching protective device). Fourth, well let the pipe be good. And what ... At my place of production or I live in a seismically dangerous zone ...

    I don’t understand why the iron pipe protects. From short circuit, electric shock? The pipe, in my opinion, primarily protects against mechanical stresses on the cable.

    At the expense of cable, guys, designers, you saw the market for electrical products in real life, and not on a computer monitor. Here you will not guess with the cable section (you buy one, actually another), and you talk about LS and ng. Everything burns and everything melts. No offense and respect for the PUE)

     
    Comments:

    # 32 wrote: Ruslan | [quote]

     
     

    Corrugated pipe material - self-extinguishing PVC composition - eliminates possible cable ignition from short circuit and flame propagation through the pipe and cable; is an additional insulator.

    It's just that some people speculate on their work.

     
    Comments:

    # 33 wrote: ohhh | [quote]

     
     

    I'm going to make hidden wiring in the steam room ... I got to the site, read a lot of interesting things about corrugation. I'm not an electrician, I want to figure it out. For me, the response of the participants to Dmitry’s comment is VERY interesting. Indeed, what can happen with wiring without connections in the corrugation under the lining (taking into account the definition of the corrugated pipe 32 of Ruslan's comment). For information, I want to connect two lamps in series.

     
    Comments:

    # 34 wrote: Digbyest | [quote]

     
     

    PUE 2.1.36, table 2.1.3

    Open installation on a combustible base only in a non-combustible pipe.The DKC website explicitly states that the PVC pipe is not combustible (it is metal, asbestos-cement, etc.). You can use non-combustible FRLS insulation without a pipe at a height where fur protection is not needed.

     
    Comments:

    # 35 wrote: Roma | [quote]

     
     

    PUE 2.1.36, table 2.1.3 ALLOWS an open cable routing in a sheath of fireproof materials. Hard combustible (difficult to combustible) - substances and materials that can burn in the air when exposed to an ignition source, but are not able to burn on their own after its removal. An ordinary VVG cable is just that (with a single installation). In the pipe or not is not important. About saunas - see GOST R 50571.12-96

     
    Comments:

    # 36 wrote: | [quote]

     
     

    I observed the consequences of one fire, though not internal (from electrical wiring), but external (closed an expensive generator control unit, which, thanks to good traction, burned out completely (the material is clearly not NG)). The corrugation put on the self-supporting insulated wire tightened, but the polyethylene wire itself was not damaged.

    And on the account of “lazy people and squabblers”, it’s hard to convince the customer that his electrician should be in metal, with plastic plumbing (that is, more expensive). So what follows is no further warning of incorrectness.

     
    Comments:

    # 37 wrote: | [quote]

     
     

    From fires caused by the thermal effects of short circuit currents, incl. overload, should protect the protective equipment, not the corrugated pipe.

     
    Comments:

    # 38 wrote: | [quote]

     
     

    And the cable channel also seems to be made of PVC, but at the same time it is laid on a piece of wood, although it does not have localization ability.

     
    Comments:

    # 39 wrote: | [quote]

     
     

    I read everything, a very interesting discussion! But most agree with # 31 wrote: Dmitriy | !

     
    Comments:

    # 40 wrote: | [quote]

     
     

    Zhora, our theorist. Yes, if everyone did as you advise, then half of the electricians would be left without work, and half of the customers would be without money
    Often in private housing construction, combustible walls are sewn up with drywall - logs, timber, frame houses. And you think that they do hidden wiring in metal pipes? Yes, no one even thinks about it! They make it in the corrugated pipe and that's it.
    Yes, of course not by the rules! What is there to do? You compare the estimate according to the rules and not according to the rules! Yes, the client will send you the rules, and hire another who will do a little not according to the rules but cheaper at times!
    To argue on this topic with such theorists, designers like Zhora does not make sense and is useless, but the author is well done. I wrote it right. I read with great interest.
    And Zhora and the like, let them design a second water supply system in the house from metal pipes for electrical wiring and sell the "right projects" to customers. That's just who will implement them in life - to look at such clients.
    And there’s nothing to teach Andrey what to publish on the site, you Zhorochka try to make such a site and fill it up, and then advise it.

     
    Comments:

    # 41 wrote: Denis | [quote]

     
     

    Quote: Polyvinyl chloride is used that does not burn and does not emit caustic smoke, not exactly like that, yet hydrogen chloride, etc. stands out, but how much it already depends on the brand of PVC, just as there is a cable VVG-ng and VVG-ng LS (Low Smoke) there are corrugations from different brands of PVC. As an option - anyone who wants to reinsure, put on a metal corrugation over a PVC corrugation, it is possible with a PVC coating (from corrosion). Of course, it is better to lay on combustible substrates even in such a “sandwich”, but if it’s open, then as an option: high-quality VVG-ng / ng LS or another self-extinguishing cable, then PVC corrugation (better LS) can be reinforced and metal corrugation (it can also be reinforced) ) with poly. coating, underneath all this, lay a layer of non-combustible material throughout the corrugation so that on both sides from such a “sandwich” they protrude by 1 cm or better a little more (for example 1.5 cm) and of course high-quality machines and RCDs, and not exceed the loads for this section and automatic / ouzo.Or another option - the metal-plastic pipe is not made of polyethylene, but of course made of self-extinguishing PVC, well, as I described above, put a non-combustible gasket on it. In short, there are different “sandwiches”, but only if not hidden wiring. it all depends on the condition of the laying and destination and the load on this network. but you can be 100% sure that the arc from the KZ will not be able to burn such a sandwich and what the consequences can be shown only by a dozen field experiments with corrugated PVC and metal of different thicknesses, different combinations of "sandwiches" made of PVC and metallophore, cable of different brands and cross-section and different loads with different short-circuit currents. In short, experimenting is necessary and this will only give an approximate idea; for more accurate data, 1000 such experiments are needed.

     
    Comments:

    # 42 wrote: a drop | [quote]

     
     

    Here, many write about the inadmissibility of asbestos in residential premises.
    So here. Asbestos dust is harmful by inhalation. And in horse quantities.
    Moreover, there are many asbestos in the world, and the chrysotile asbestos used in Russia is the least harmful.
    So from the asbestos gasket under the wiring there will be no harm.
    Unless you specially rub it into dust and inhale.

     
    Comments:

    # 43 wrote: Paul | [quote]

     
     

    Corrugated pipes - yes, in the kitchen inside the headset or in the barn, you can use this solution, but if you lay such pipes in the apartment in full view - it will be very aesthetically pleasing, in extreme cases, the corrugation will again have to be masked with a special casing.

     
    Comments:

    # 44 wrote: Nikolay | [quote]

     
     

    For lighting devices, electrical installation is usually carried out by a corrugated hose with a diameter of 16 mm with a wire of 3x1.5 mm2

     
    Comments:

    # 45 wrote: Anatoly | [quote]

     
     

    PVC corrugation (lightweight, for indoor installation) can be of two types - from new plastic and from secondary plastic, for example, corrugation with an outer diameter of 25 millimeters from new plastic has an inner diameter of 20 millimeters, from secondary plastic - 18 millimeters, corrugation with an outer with a diameter of 20 millimeters from new plastic has an inner diameter of 14 .9 millimeters, from secondary plastic - 14 .1 millimeters, a corrugation with an outer diameter of 16 millimeters from new plastic has an outer diameter of 13.2 millimeters, from secondary plastic - 10.7 millimeters Measuring the internal diameter of the corrugation, you can immediately understand what plastic the corrugation is made of. Moreover, for laying a copper three-core cable, one core of which serves as a protective conductor, with a cross-section of a 2.5 mm square core from the VVG series, according to NTD, only corrugation made of new plastic with with an outer diameter of 20 millimeters on short sections of lines and corrugations with an outer diameter of 25 millimeters, both from recycled plastic and from new plastic. The main purpose of the corrugation is to ensure the constancy of the nominal cable current and the condition of its cooling, when laying it on various building materials with different thermal conductivity, due to which it is possible to clearly protect the cable from overload currents and short circuits So for a cable from the VVG series with a cross section of a 2.5 mm square core, the rated current when laying in light PVC corrugation with the outer diameter of 25 millimeters is 21 amperes, while the temperature of the cable core is + 60 degrees Celsius at an ambient temperature of +20 degrees Celsius. The cable can store this current to a temperature of + 30 degrees Celsius with a core temperature of + 70 degrees Celsius. However, commercially available cables from the VVG series according to GOST, even with the addition of lead to the commercially available insulation of conductors of grades I 40 - 13A, with an average core temperature during operation of + 50 degrees Celsius , have a real life, according to control tests, only 14.5 years instead of 30 years provided by the technical documentation, and the cable sheath from a commercially available OM plastic hose compound is 40, with an average sheath temperature during operation of + 50 degrees Celsius, It has a real life of 25 years, the service life of cables from the VVG series, manufactured according to TU, is even shorter, and their technical characteristics are even worse. It is very risky to lay these cables directly into the stucco under the plaster without corrugation. However, a properly laid cable corrugation allows you to have corrugations on the surface,at a nominal cable current of 21 amperes, have a temperature equal to + 20 degrees Celsius at room temperature. In this case, the air temperature in the corrugation reaches + 25 degrees Celsius, due to convection of the heat flux of the cable into the air and the corrugation, as a result of its heating by the current flowing through it. Taking into account the transitional convection resistance of the cable, the temperature of the outer surface of the cable sheath is + 45 degrees Celsius, and the temperature of the cable core + 60 degrees Celsius. An automaton for a rated current of 13 amp should be used as protection p, which at room temperature already has a nominal current of 14.5 amperes, and the maximum continuous current of the cable, taking into account its dead zone of 13%, is 16 amperes, the current of 1.45 rated current is 21 amperes. At the maximum continuous current of the cable, its core temperature is + 45 degrees Celsius, which provides sufficient thermal stability of the cable to short-circuit overload circuits and its long and reliable operation