The installation of hidden electrical wiring is carried out even at the construction stage or at the very beginning of the repair, when there is only a rough finish in the room. This option is considered optimal, since it allows you to completely hide the wires from the eyes. However, the work requires effort on the walls chasing and subsequent putty. However, if there is a laying on the floor, then the scope of work is simplified. So how do you hide the wiring?
Shall or not?
The average thickness of the plaster, in which any hidden wiring could be hidden, is 6-7 mm. In most cases, the standard finish will do the job completely. However, if it is planned that the thickness of the plaster layer will be only 3-4 mm, it would be more expedient to first plaster all the walls, then make the channels of the required size and cover them again after laying the wire.
An important point: before installation and immediately after it is completed, it is imperative to check the cable for integrity. For this, a probe lamp or a special indicator is used. Remember: repairing hidden electrical wiring in the event of an error will require much more effort than unnecessary control over the process.
general description
Before starting the laying of strobes, it is required to draw in advance the lines along which they will pass, and subsequently hidden electrical wiring will be laid.
In order for the lines to be strictly vertical or horizontal, a level is used. Do not make them too high or low, so as not to interfere with the subsequent installation of the floor or false ceiling. Experts recommend making a stock of 15 cm. The places of future fastenings are also noted, the recommended step is from 20 to 40 cm.
At the second stage, holes are cut for the boxes (more often a puncher is used), and connecting grooves are made with a grinder or a special chasing cutter. It remains to make hatches in the boxes, the conductors are put into place and fixed. Further, they do the same with the cable between them. Upon completion, all installation boxes and cables are masked with plaster, and at the end of the work, switches and sockets are installed.
Gutting
If laying the cable during rough finishing is not possible or the thickness of the plaster layer is insufficient, it becomes necessary to groove. This term means making a rectangular groove for the subsequent laying of hidden wiring.
The strobes are made using a special chasing tool or an ordinary grinder. The first one is not so popular because of its high cost and rarity (that is, it is unlikely to take it from a neighbor), but it allows you to cope with the task as quickly as possible and with the least labor costs. In the absence of a tool, a chisel and hammer are used. However, this option is fraught with possible chips and damage to the plaster.
The parameters of the groove depend on which conductors and in what quantity are planned to be used in hidden wiring.
The depth should be chosen to hide the wire in the furrow with a margin. Most often, the best option is 2, maximum 2.5 cm. The width is somewhat more complicated: it is necessary to ensure a distance of at least a few millimeters between the individual wires.
Before plastering the wall again, it is necessary to thoroughly clean the accumulated debris from the strobes, and also cover them with a primer. The work with the junction boxes is carried out at the final stage, so in the beginning you just need to leave the wires hanging. This is very important as it is difficult to predict in advance exactly how deep the boxes will be installed.
Fasteners and installation
For brick and concrete walls, all experts recommend using a dowel-clamp or UW as an attachment. In common parlance, it is also often called "uveshka". To work with cords 3x1.5 or 3x2.5, you will need a mount marked 5/10. To drill the holes for the fastening, use a drill with a diameter of 6 mm. During installation, the dowel is wrapped with a cable and inserted into the hole, the antennae key in the system become a spacer, which is wedged in the strobe.
Separately, it should be noted cases when the cable needs to be rotated 90 degrees. This should be done carefully, ensuring a sufficient turning radius. The exact numbers can be found in the specifications of the cable used.
Laying cables in pipes
For greater reliability, in some cases, hidden electrical wiring is installed in pipes made of PVC or corrugated. This method is not used so often and is only in demand in rooms where temperature or humidity drops often occur: baths, buildings without heating, and the like.
There is practically no difference between the installation of conventional hidden electrical wiring in an apartment and installation in pipes. The key difference is that in the case of pipes there are concessions to the requirements, for example, overlapping of cables is allowed. However, the strobes for them will have to be done much more. The pipes are fastened in the same way in the case of a small diameter, or with brackets if the diameter exceeds 4 cm.
Fast-setting gypsum can be used as an alternative fastening approach. It will help increase the reliability and fire safety of the system, but it is much more difficult to work with it. True, if you want to remove the cable from the pipe, if necessary, it will also be much easier.
Place of laying - floor, partition, ceiling
Separately, it should be noted the options when hidden electrical wiring is mounted in floors, ceilings or partitions. For example, if we are talking about a suspended ceiling made of plasterboard with a metal frame, then it will be much easier to hide the wiring, you do not even need to gouge the walls - the conductors simply hide under the ceiling, and go down at the right points.
Also, junction boxes can be placed under the drywall, but for them you will have to attend to the embedding of hatches opposite. Hatches are used to gain access to hidden wiring if necessary. Clamps or UW are used to fix the lighting cables to the ceiling.
The best option: hidden electrical wiring is first hidden in the pipes, and they are already mounted in the ceiling. Such a solution allows to increase the fire safety of the plasterboard structure, installation is done with clips.
Installation of hidden electrical wiring under the flooring is carried out in a similar way. The easiest way is to mount cables to the floor if it is made of wood or gypsum fiber. In the case of a tree, holes are made in the logs into which pipes are inserted, along the line and a cable is laid. Alternatively, concealed wiring can also be arranged over the floor surface. First, level the surface with expanded clay or a similar mixture, apply a topcoat on top.
Some equip hidden electrical wiring in the apartment, hiding the wires in pipes, and then filling them with cement. This should not be done, especially if it is planned that the layer of solution above the pipe will be small.
An important point: if you decide to hide the wiring under the floor or ceiling, connections are allowed only in specially designed boxes. Only in this way, in case it fails, it will be possible to get to it relatively quickly.
Often, the installation of hidden wiring is carried out behind drywall and in partitions.
As practice shows, often non-specialists make a common mistake, they forget about protective shells.
In an attempt to get by with minimal effort, holes are made in the metal profile itself. Also, do not pull wires through drywall before you sew it on. In both cases, there is a high risk of damage to the insulation. It becomes very problematic to pull out the conductor for repair. This problem is solved in an elementary way. Before pulling the conductors through the holes, you should put them in the pipes in advance.
Lighting is much easier to work with. The voids in the slabs play a key role here. They remain from the stage of installing the floor. This solution is also attractive in that it does not require any gating. However, this does not affect the protection of the cables. It is enough to punch two holes: near the wall and at the location of the lamp. To pull the wire through the pipes, special probes made of rigid wire are most often used.
It remains to note the case when the hidden wiring is mounted through the insulation in the walls. It is preferable to lay through mineral wool because of the individual characteristics of the material: it is lightweight, excellently compressed and does not require any additional work. Many people prefer polystyrene, but additional pipe channels will have to be cut through it.
Installing the back box
There are also nuances here. It is worth starting with the fact that in rooms with concrete walls, it is recommended to use diamond-coated bits, since the more common models with victorious coating wear out quickly, and you will have to buy additional drills. They can only be used in houses with finblock walls. Characteristically, when working with finblocks, it is forbidden to use diamond-coated bits for the same reasons.
Before starting milling, a hole is made in the mounting center with a diameter equal to the drill, so that there will be much less difficulties during work. Experts recommend choosing boxes with a diameter of 6-7 cm, this will be enough for 6 cores. If you plan to connect several outlets in a row, the place for them is leveled.
Wire quality
It is worth remembering that the reliability of the hidden, and indeed any, wiring depends not least on the quality of the wire. There is a wide range of conductors on the market today. Their main parameters are as follows:
- the cross-sectional diameter of the conductor can be from 800 to 0.75 mm;
- core material (most often copper, aluminum or their alloy);
- the number of lived up to 37;
- wire sheath yarn, rubber, paper, plastic (more protected wires have two types of insulation at once).
For wiring at home, cables are used under the NUM and VVG markings, as well as ShVVP, PUNP wires and a number of others. It is worth briefly describing the main features.
VVG is a cable without armor, the cores of which are copper, and the insulation is vinyl. There are several varieties on the market with additional marking: VVG NG is distinguished by increased fire safety, VVG Z has additional insulation, etc.
NUM - high strength cable for the organization of hidden wiring. Poorly suited for use as the outer shell is poorly resistant to sunlight.
PVS - connecting wire for any type of work.
PBGPP and PBPP - wires for laying lighting lines. They differ in the presence of an additional flexible conductor.
ShVPP - copper wire of increased flexibility.
In general, making hidden wiring at home with your own hands is a difficult task, but quite accessible even to a layman. The main thing here is to strictly observe the above-described technology features and nuances, and then high-quality wiring will be able to please for many years.
Hidden wiring allows you to aesthetically arrange the wiring network over the area of \u200b\u200bthe room. In this case, switches and sockets protrude minimally beyond the level of the walls. Such wiring is stationary and is planned at the stage of overhaul. This article will tell you how to properly make hidden wiring
Concealed wiring device
There are two opinions as to which wiring is considered hidden. Some experts say that hidden is the one that is not visible. It is laid in a groove or mounted under the skin. Others argue that hidden wiring must also include cables placed in tubes and channels.
Consider the first, classic version, in which all specialists are similar. That is, the placement of wires in the thickness of building structures. Namely, in partitions, ceilings, floors, wall voids and suspended ceilings.
It is necessary to proceed with the installation of hidden wiring during repair work. Ideally, before applying the finishing coat of putty.
Usually the wires are placed in a specially made strobe. These grooves are made with chasers and a grinder. For household repairs and a small amount of work, a puncher or a scalpel with a hammer is used.
The wiring must have a second sheath or be placed in protective pipes or ducts.
Requirements for hidden wiring in the house
The most important requirement for hidden wiring is fire safety. Its installation in wood and flammable structures requires special care. Therefore, the wires are placed in steel or PVC pipes.
It is necessary that the elements of the cable system are easily replaceable. This rule is rarely followed. And the manipulation of replacing and adding wiring is forced to destroy the structure's coating.
Wiring is carried out vertically and horizontally relative to one of the walls. This will save materials and funds, simplify the work process. And for future repairs, it will simplify the search for a network of wires.
Before installation, plan the cable system. It will not be superfluous to indicate the location of all electrical boxes. The hidden wiring scheme is carried out and saved for the future. When it changes in the process of work, the appropriate adjustments are made to the plan.
The electrical safety of hidden wiring is important. Experts advise using three-core cables. And connect the yellow-green ground wire in the future, if it was not provided initially.
You also need to take care of the residual current device.
Hidden wiring diagram
Installation of hidden wiring is carried out in a specific sequence.
First, the type of network branching is determined: boxed or daisy chain.
First, it involves laying one cable over the area of \u200b\u200bthe entire apartment. Another wire is diverted from it to each room. This branching is done in a junction box.
The European type loopback connection involves two wires. One is for sockets, the other is for lamps. They exit from the switchboard into each room. Which contains a switch for each hidden wiring cable.
After that, the locations of the luminaires and branch boxes for the hidden wiring switches are determined.
It is necessary to consider the path of the wires. They are placed 15 cm below the ceiling or 10 cm from a beam or cornice. The distance to door and window connectors must be at least 10 cm. Routes to the sockets are laid at their level. Lifts are made perpendicular to the floor to the places for lamps and sockets.
The lined diagram on paper is transferred to the surface of the structure.
Materials and equipment for hidden wiring
When installing hidden wiring in a house, it is optimal to use a cable with a cross section of 2.5 mm for VVG sockets. It is based on double-shielded copper conductors. And for the connection for lighting devices - PBGPP with a diameter of up to 6 mm. It is a flat wire for hidden and exposed wiring, which consists of one flexible core.
All types of switchboards are suitable for wiring. The same can be said for sockets and switches. True, the socket for hidden wiring takes up less space and looks more aesthetically pleasing.
Boxes for hidden wiring are selected based on the type of walls. They are available for hollow and solid structures. Sometimes for this purpose, socket boxes are used, which are closed with homemade lids.
To securely connect the ends of the wires, purchase plastic PPE caps or terminal blocks.
A chipping tool is required to install the cable. A hammer drill is enough for a home electrician for this task. For work on concrete, you will need equipment with a capacity of 1.5 kW. You will also need a cable cutter and a plastering knife.
And to secure the wire in the grooves, stock up on dowel clamps, an assembly strip and alabaster mortar.
DIY hidden wiring
After determining the type and drawing up a wiring diagram, the stage of its installation begins.
Install a distribution box at the cable entry point into the apartment.
If the repair involves plaster of 0.9 cm or more, fix the wires in it. Sometimes wires are laid along the walls and covered with a baseboard. This does not really save money, but it puts electrical communications at risk.
It is safer and more practical to place hidden guides in furrows. In order not to stumble upon metal fittings, first check the place for the wiring with a metal detector.
The width of the groove must accommodate all wires. Then, due to friction, they lie firmly in the channel and do not fall out of it. The depth of the furrow corresponds to the thickness of the cable plus the space for leveling with plaster. Usually 8 - 10 mm is enough.
Places for sockets and boxes for hidden wiring are made with a perforator with a "crown". If the power of the tool is not enough, then the nozzle is replaced with a drill.
For reliability, the wires are supposed to be placed in cable ducts, which must initially be fixed in the strobe. And the wires themselves are pulled inward with a flexible wire.
If additional protection is not used, the harness is fixed in the furrows with alabaster.
Sockets and their outer frames are installed.
Wire strands at wiring crossings are connected in junction boxes. They protect the ends of the cables from dust, moisture and mechanical stress.
The strobe is plastered from above according to the general level.
It usually takes 2 to 3 business days to replace internal wiring in one room.
Wiring hidden wiring in a wooden house
Particular attention should be paid to the electrical network in a wooden house.
The ideal option is the integrity of the cable without the use of boxes. So each wire from the machine goes to a separate end to the load point.
It is necessary to remove the wiring from the flammable structure as much as possible. Therefore, laying wires over a wooden base is prohibited. And impregnation of wood with non-flammable substances is useless over time.
The wiring is laid in a metal sleeve. To avoid endangering the house in case of fire. The pipes are tightly welded together. Or fastened with bolts.
The plastic counterpart is not as durable. And rodents can feast on it. If the wiring is still in plastic pipes, protect it with non-combustible materials. For example, concrete, alabaster or plaster.
The cable should occupy no more than 40% of the space in the pipe. And the thickness of its wall is selected based on the section of the cable. So for copper wires:
- with a core diameter of 4 mm - the metal of the sleeve is at least 2.8 mm,
- from 6 to 10 mm - 3.2 mm,
- from 25 to 35 mm - 4 mm.
Requirements for aluminum wires are half as much. So with a cable diameter of 7 cm, a pipe with a thickness of 4 mm is required.
The sockets are placed in metal sockets.
Wiring is carried out using non-flammable wires. For example, VVGng, RKGM, NYM and VVGng LS.
All metal pipes are grounded. To slow down corrosion processes, the metal is covered with a special paint.
The copper sleeve is more expensive, but more durable and easier to install than the steel counterpart.
For safety, it is necessary to install two panels: with automatic devices and switches.
The electrical network is thought out so that there is access to it, without destroying the wooden frame of the house. For safety reasons, the junction boxes remain freely accessible.
1. Run the wiring during the initial repair phase. When, apart from the rough walls, floor and ceiling, there is nothing.
2. Before installing the wires, check the integrity of the indicator. After - repeat the action.
3. Trace surface wiring lines for accurate wiring. This is easy to do with a building level and / or rangefinder.
4. No lighting during wiring. An autonomous energy generator or neighbors will help to solve the problem.
5. After slitting it is necessary to clean the furrows from dust with a brush. Then treat with a primer.
6. When installing wiring in drywall structures, be sure to use protective sheaths.
7. Do not forget to leave a margin of cable length at the points of connection with sockets, switches and boxes.
8. Use the same cables: copper or steel. The connection of two different metals is more susceptible to corrosion.
9. New wiring requires permission to connect to an external power source. Therefore, you cannot do without a specialist.
10. Switches are usually placed at a height of 1.5 - 1.7 m on one side throughout the apartment. At the same time, so that the open front door does not block access to them.
11. According to fire regulations, for every 6m² there is at least one socket, in the kitchen - three.
12. If it is necessary to cross wires, their insulation is increased. For this, 3 - 4 turns of electrical tape are made around each cable.
Strobes in brick before plastering work
Attachment is carried out using plastic brackets. Of course, all electrical wires must go along those routes that are determined by the diagram (we will note the rules for placing wires below).
In addition to the installation of the wires themselves, socket boxes are immediately mounted. It should be borne in mind here that these boxes should not stick out over the plaster.
Therefore, you should decide on what thickness the plaster will have and, depending on this, make holes with a drill in a brick wall. The mounting boxes are fixed in the holes made with alabaster. The ends of the wires are brought out into these boxes.
Also, before the process of plastering the walls, junction boxes are mounted. They should be in every room. Their installation is no different from installing socket boxes. In the middle of them, cables are also brought out.
As for the type of cables, a VVGng or NYM copper cable should be installed under the plaster. The latter cable is the preferred option. They have a PVC sheath that does not support combustion and emits a reduced amount of smoke in the event of a short circuit.
If there is a desire to use other wires (PVA, APV or PV), then they need to be mounted in boxes or pipes. To pull the cable through the pipes, an elastic plastic broach is used. First, it is pulled through the pipe. Next, the cable is securely attached to it and, pulling the broach, tighten the new wiring.
Helpful advice: the most ideal option for laying hidden wiring would be to install plastic pipes on the walls of a brick house, through which the cables themselves will pass. The convenience of these pipes lies in the fact that if in the future it is necessary to replace the wiring, then there will be no difficulties with dismantling the old and installing new cables. In this case, it will not be necessary to groove the walls and the replacement process itself will be very simple.
When all the wires are laid, distribution and junction boxes are installed, then plaster is applied on top. This option of wiring is possible if the plaster layer is thicker than the cables.
In the event that you plan to apply a little plaster, i.e. its layer will not be very thick and the cable cannot be hidden in it, then strobes (channels) must be made in the brick walls. In them, the laying of hidden wiring will be done. We will describe the features of creating strobes below.
In practice, it often happens that the owners do not want to apply plaster to the walls, but instead install gypsum boards. In this case, everything is very simple, since each wire can be safely attached to the wall with brackets, and all hidden wiring will be placed behind a sheet of drywall. Of course, the placement of electrical cables must comply with the electrical circuit and the rules defined by the PUE. 
How to place electrical wires
Let's dwell on the rules for placing electrical cables. They should only be placed vertically or horizontally. Diagonal placement is prohibited. An exception may be diagonal laying in the attic, however, provided that the cable is placed parallel to the ceiling line.
Horizontal laying of hidden wiring is recommended to be done at a height of 30 centimeters from the floor level, or at a level that is 30 centimeters below the floor level. The wiring can be carried higher, however, there must be at least 15 centimeters between the floor and the wiring.
Helpful advice: it will be better if the distance between the overlap and the wiring hidden in the plaster or behind the drywall is 30 centimeters. This will avoid complications when installing a false ceiling.
When it comes to vertical routing, there are also some limitations. The distance from the corner of a wall, door frame or window opening to the cable should be more than 15 centimeters. If a gas pipe runs along the wall, then the wire should be located at a distance of 40 centimeters from it.
Gasket with strobes
The methods described above for laying hidden wiring concerning the case when the house is being built and the organization of all engineering systems is only being carried out.
Strobes in plaster for wiring
However, there are many cases where brick house owners want to replace old wiring with their own hands. In this case, additional difficulties already arise.
They are connected with the fact that all the old wiring is hidden under a layer of plaster, and in fact, in this layer, you will have to lay new wiring. In order to install it, you need to make channels in which the electric wires will be placed.
The peculiarities of drilling out the grooves depend on the thickness of the plaster layer. If this layer is thicker than the wiring that will be laid, or the tubes in which the cables will be placed, then only the plaster is slit.
In this case, we can say that you are lucky because you do not have to put in much effort. However, if the thickness of the plaster layer is insufficient, then you will have to chisel the brick wall. And this is much more difficult.
Slitting brick walls is also carried out with certain rules. So, the channel should not be wider or deeper than 25 millimeters. One strobe should not be longer than three meters. Horizontal channels cannot be made on load-bearing brick walls. Also, it is impossible to gouge floors (with the exception of plaster on the ceiling).
In addition, ducts should be made in such a way that there is a minimum number of corners between the locations of the switch / socket and the junction box. Of course, it is better to make only one angle of transition from horizontal to vertical strobe. Wall joints in this case are not taken into account.
Ways to create strobes
They can be done with:
- hammer and chisel;
- hammer drill or hammer drill;
- grinders;
- wall chaser.
The most ideal option is to use a wall chaser. Thanks to him, the strobe will have the required depth and width, and will also be even.
In a brick house and any apartment, strobes are made according to the routes for laying new wiring. These routes are indicated on the diagram.
According to the diagram, markings are drawn on the walls. It should be two parallel lines that extend from the location of the junction box to switches, sockets and lights.
Helpful Hint: Before applying the markings in the places where the grooves will pass, you should check for the presence of live wires. This will increase the safety of all work.
According to the markings made, the walls are slit. This process is very noisy and a lot of dust is emitted during it. Therefore, goggles, gloves and a respirator must be used for protection.
If you plan to chisel the wall with a hammer drill, then you need to use a wide and short drill, as well as a spatula. First, having equipped the perforator with a drill, holes are made along the entire length of the groove.
The distance between them should not exceed 15 millimeters. The hole must have a depth of 25 millimeters. Next, remove the drill and install the blade.
After that, the necessary pieces of the wall are chipped off. Do not place the spatula across the groove itself. This can cause most of the plaster to chip off.
If you are going to use a grinder, then it must be equipped with a diamond disc. She sawed both edges of the groove. Next, take a punch and release that part of the wall that is located between the sawed lines.
It should be borne in mind that when using the grinder, a large amount of dust will be generated. This dust must be removed with a powerful vacuum cleaner. It is advisable that a second person holds the pipe of the vacuum cleaner.
As for the chaser, it has two discs, which will cut the two lines of our channel. Of course, these discs must be diamond. The wall chaser is designed in such a way that dust does not enter the room. When the grooves are ready, they are cleaned and primed.
In a similar way, places are made for placing junction and junction boxes. They are mounted on alabaster. After that, the necessary wires are already installed.
Again, the wiring can be installed in the very grooves and applied on top of plaster, or it can be placed in plastic pipes. Cables or pipes are secured with spacers, staples or alabaster. After laying the wiring, the grooves are filled with plaster.
Some features of drawing up a diagram
These are the ways of laying wiring in a brick house using your hands. Accordingly, one of these methods must be taken into account when drawing up a scheme for laying new wiring. It should be noted that the scheme is mandatory and must be approved by the relevant authorities.
Earlier we specified the rules for posting. They should also be taken into account in the scheme. It is also worth noting that the circuit must provide at least two separate wiring branches.
One must power the illuminated devices (for this, you can use a wire with a cross section of 1.5 square millimeters), the other must supply current to the sockets (the cross section of the electrical wires must exceed 2.5 square millimeters).
There should also be separate branches for powerful consumers of electricity. Each room must have at least one junction box.
Necessary materials and tools
After you have drawn up and approved a wiring diagram in a brick house, you can start purchasing the necessary tools and materials.
Materials must be submitted:
- electric cable;
- mounting and wiring boxes;
- alabaster;
- terminal blocks;
- staples;
- metal sleeves and plastic sleeves.
As for the tool, in addition, with the help of which the strobes will be made, you need to take:
- Hammer.
- Side cutters.
- Chisel.
- Pliers.
- Assembly knife.
- Screwdrivers.
- Voltage indicator.
- Multimeter.
When all materials and tools are prepared, proceed to laying the wiring in the brickwork using one of the methods described above.
In the event that the wiring will pass through the wall, then you need to make a hole in the wall and insert a sleeve into it. Plastic sleeves are mounted on the edges of the sleeve.
At the end, all wires are connected and measurement work is carried out.
Carrying out work on laying wiring in a brick house
Owners try to create most modern living spaces with perfectly aligned walls, floor and ceiling without unnecessary protrusions, and all electrical communications are hidden inside building structures. This allows for a unique design, restricts access to electrical wiring, but complicates its inspection and maintenance.
The technology of installing hidden wiring can be performed in various ways, which are constantly being improved with any method of building construction. For each specific case, choose the best option that meets two basic requirements:
reliability of work;
safe operation.
The cost of installation should also be taken into account, but it should be considered not at the time of laying the wiring, but considered in conjunction with ensuring the possibility of long-term, safe operation, excluding the occurrence of malfunctions, emergencies, including the consequences of their elimination.
Concealed wiring diagram
Its presence is a mandatory attribute before starting electrical work. Design organizations create documentation at a professional level, take into account the rules of safe operation, the necessary protection, specific requests of the owner.
Self-drawing up a closed wiring diagram without proper experience can complicate the work, lead to unnecessary waste of material resources, the creation of serious mistakes, for which electricity punishes.
Experienced electricians can do their own installation scheme. A separate issue is devoted to this issue. We recommend that you carefully read it.
Requirements for highways for laying wires
In hidden wiring, current-carrying conductors of cables and wires must provide two functions:
1.current flow through the elements of the electrical circuit with minimal power losses and voltage drops;
2. Reliable isolation of the formed chains between themselves and the ground contour, excluding the occurrence of short-circuit currents and leakage.
The choice of wire for metal core
To solve the first problem, the trade provides the consumer with a choice of wires and cables with metal conductors from:
aluminum;
or copper.
The advantages of aluminum conductors include:
1.lighter weight;
2. reduced cost.
However, they have disadvantages:
underestimated mechanical strength, providing fracture after several bends, twists and tensions;
increased ductility of the wire in the clamped terminal. When it is heated from a current load, additional deformation of the metal occurs due to the expansion of the contacting steel parts. After cooling, the steel returns to its original dimensions, while the aluminum remains in a reduced size. The contact weakens, and the resulting oxide film layer on aluminum further degrades the electrical resistance at the junction, which leads to overheating, arcing, fire, and fire.
In a closed modern wiring, even at rated loads, a high heating of the wires is created. Heat removal from them to the external environment is limited. Plastic and weak aluminum in such conditions is prone to malfunction, is prohibited.
Choosing copper.
Insulation dielectric properties
The outer sheath of current-carrying conductors can have one dielectric layer on the wires or several on the cables.
Trade provides cable products intended for the transmission of electrical energy of various voltages from low-current circuits of several tens of volts to high values \u200b\u200bmeasured in kilovolts.
In a household network, it is sufficient to use conductors with insulation that can withstand 0.4 kV. They cope well with loads arising from short-term emergency situations associated with overvoltages in the power supply circuit, which are eliminated by appropriate protections.
However, when choosing a cable, you should pay attention to its fire-fighting qualities. In a closed version, the wiring can be exposed to high temperature loads. It must be non-flammable.
This parameter is indicated in the marking with "ng" symbols, for example, VVGng cable 3x1.5. Simple insulation of conductors during overloads in the network can ignite, sustain combustion, and cause a fire.
About flat wires PUNP, APUNP
Cable products of this brand, deciphered as flat wire with universal properties (the letter "A" denotes aluminum inside a conductive core, not copper). PUNP wires have long since become a household name.
They are produced not according to state standards, which are law, but according to the local technical conditions "TU" of the manufacturer's enterprise. The cross-section of the conductors indicated on the nameplate can be reduced by up to 30%. The insulation layer made from low-quality materials is also understated.
Even with a double sheath of insulation, PUNP wires do not meet safety requirements, they are the cause of numerous fires in household electrical wiring.
The use of wires of the PUNP and APUNP brands in closed or open household wiring creates increased risks for the life of people, the safety of property.
Directions of hidden wiring highways
It has long been a rule among electricians to orient the wires in a monotonous manner within building structures with maximum observance of horizontal and vertical lines located at right angles. They correspond to the main directions of architectural structures.
This technique makes it easier to find faults in closed electrical wiring, allows the owners to better navigate with the drilling of walls when installing fasteners for furniture and accessories.
Features of the installation of electrical wiring in panel buildings
In older houses made of reinforced concrete panels, the method of placing wires horizontally and vertically was often violated in the past in order to save materials. In the slabs for walls and ceilings, during their casting, special tubeless voids and recesses were created for laying electrical lines. These channels were located at arbitrary, but typical angles for the entire series of buildings.
It is not required to be engaged in marking the places of installation of electrical appliances and laying cables with this method. Recesses are created at the joints of building structures for connecting electrical wires. At one of the wall panels, niches have been prepared for placing the apartment switchboard and low-current circuits.
You can get acquainted with a similar arrangement of cable lines in the construction technical documentation or check the passage of the routes from neighbors or service electricians.
When pulling wires in such channels, check the cross-section of their free space by pulling the gauge, as well as the absence of cutting edges that can damage the outer insulation when winding the cable.
The tightening force of the wires into the prepared cavities is limited to 20 N per 1 sq. Mm of the total cross-sectional area of \u200b\u200bthe conductors used. When the free channel diameter is 20 mm, then it is permissible to place 5 wires with a cross-section of 2.5 mm square in it, and for 25 - 8.
Features of the installation of electrical wiring in buildings from building blocks and bricks
Concealed installation is associated with the performance of a large amount of dirty, dusty work on the processing of wall material and building structures. It is better to carry out it before finishing the premises.
The work begins with the marking according to the design scheme and the execution of electrical points - the places where the cables are switched with wires and where sockets, switches, lighting devices, junction boxes, shields and other electrical equipment are located.
Then all electrical points, starting from the lead-in or apartment panel, are marked with lines for laying cables between the electrical points. According to the markings made, recesses are created in building structures.
For indoor installation in a plastered wall, the cable can be placed inside tie joints, under a layer of plaster or in.
When chasing, pay attention to the thickness of the wall and the required depth of its processing. You can not go beyond the permissible limits. Otherwise, the weakening of building structures occurs, which can cause the collapse of the supporting element.
It must be clearly understood that chipping of load-bearing structures and ceiling plates is not allowed, it is prohibited.
The cable can be placed:
1. into a pipe or corrugated hose, which is putty directly into the groove;
2. or mount without it.
In the first case, it is possible to quickly remove the damaged cable in this section from the corrugation and replace it with a new piece. In the second version, a non-separable connection is formed, which requires dirty work during repairs.
However, with the correct choice of a cable with additional protection of the sheath from mechanical damage and the exclusion of its emergency operation modes, the second method is economically justified. It is most often used in practice.
But, in this case, first, local fixation of the cable inside the groove is done, for example, with plaster or alabaster, and then the final electrical installation of the circuit is performed, the quality of its work is checked. After eliminating the errors that have arisen, the plaster of the cut line is finished.
Concealed wiring on plasterboard partitions
Plasterboard sheets are used for leveling walls, dividing rooms into zones, creating false ceilings and multi-level structures. Sockets, switches, light sources are installed on them.
The technology of installing wires and cables in this situation is less laborious. There is no need to make strobes. All communications are hidden behind the sheet. At the same time, attention is paid to the exclusion of damage to the outer layer of insulation during installation on reinforced metal structures for fastening drywall. Otherwise, leakage currents and the appearance of a dangerous phase potential on the mounting device can occur.
The best protection option is considered to be the placement of wires inside a corrugated pipe, which is attached to metal profiles and protects a layer of external insulation.
Concealed wiring in wooden buildings
Now construction companies massively produce houses from logs, glued and rounded beams. They are in demand due to natural, environmentally friendly materials, and the owners want all the comforts of modern civilization and want to operate the electrical wiring installed in a hidden way.
In carrying out such a plan, three important conditions must be observed:
1. wood, even impregnated with special fire-fighting compounds, is a combustible material. In case of damage to the electrical wiring, sparks or an arc arise, causing a high temperature, which the impregnation layer cannot withstand - a building fire is inevitable;
2. wood products contain moisture in their structure, which dries out or accumulates during operation. In the first few years after construction, houses reduce their dimensions - they shrink;
3. At low temperatures, condensation occurs in the internal conduits.
Let's analyze them in more detail.
1. How to protect wood from fire in hidden electrical wiring
On this issue, clause 7.1.38 of the current seventh edition of the PUE clearly defines three important points for our case:
1. to carry out hidden electrical wiring exclusively inside metal pipes and boxes that have a localization ability of fire;
2. use only flame retardant cables;
3. to realize the possibility of replacing damaged cables.
Features of cable protection from wood
The rules of the PUE unambiguously indicate the way of performing concealed installation of electrical lines in environments that are liable to fire, focusing on the fact that the protective sheathing of the cable should prevent the development of a fire and localize it.
The fact is that the electrical wiring can be operated with overload, when the protective devices have not yet had time to eliminate it. In this case, the insulation undergoes small but irreversible processes, gradually deteriorating its dielectric properties.
As a result of its premature aging, a short circuit occurs over time, an electric arc is formed with a temperature of about five thousand degrees. It instantly burns through the outer shell. If the cable is located near wood, then the latter will ignite.
When the highway is hidden inside a wooden wall and a fire has begun, it is very difficult to extinguish it because the fire source is hidden, it is problematic to get to it with simple fire-fighting means. The situation is aggravated by the accumulation of dry wood dust, which ignites in an explosion along the entire length of the line in a fire. When the fire flared up well and broke out, it immediately engulfs most of the structure.
Therefore, the cable must be protected from wood reliably. Since the corrugated hose burns out from the high temperature, like thin-sheet pipes, it makes no sense to use them.
On the forums of electricians, there are disputes on this issue. But, when a short circuit occurs, the cable fencing must withstand the temperature flash of the created electric arc, exclude the burnout of the metal protection, and therefore ensure the tightness of the volume.
Then there will be no supply of fresh air to the place of ignition, and the fire of the electrical wiring will self-destruct due to the lack of oxygen, as an oxidizing agent of the combustion process.
It is important to emphasize that the metal channel with the cable must be reliably sealed from the ambient air. Otherwise, self-extinguishing of the fire is excluded. For this purpose, individual pipes are connected to each other in advance in one of two ways:
1.welding;
2. sealed threaded connection.
In the second case, it is necessary to provide an electrical connection between the individual pipes. After all, the entire metal pipeline will also need to be connected to a protective grounding device in the potential equalization system to eliminate arcing or breakdown.
Cable entry into switchgears, junction boxes, sockets and switches is also sealed, and they are installed in a metal socket box.
Features of flame retardant insulation
Since the short-circuit arc current is of the same nature as that of welding, it is proposed to conduct a simple experiment with two pieces of normally insulated non-combustible cable: subject them to a high temperature.
As a result, you will see that in both cases, the outer protective coating will become burned through. But in one case, the isolation will continue to burn, and in the other it will stop.
This will help to understand that the cable marked "ng" does not protect against burnout of the emergency short circuit current, but only does not aggravate the fire. Its insulation collapses and requires subsequent replacement.
Ability to replace damaged cables
This PUE requirement also complicates the installation of hidden electrical wiring in a wooden house. In the design of a metal pipe, it is necessary to provide for hermetically sealed windows through which the faulty cable is removed and a new one is installed.
Without the technical implementation of this possibility, a clear violation of the rules for the installation of electrical installations is created.
2. Taking measures to protect hidden wiring from building shrinkage
A building built of wood with natural moisture can dry out in 3 years and settle up to 15 ÷ 20 cm per floor with its height of about three meters.
A thick-walled metal pipe mounted inside the wall will not change its dimensions. It will be affected by external mechanical loads of contiguous building materials.
To exclude deformation of the pipe, it will be necessary to introduce compensating devices into its structure, which will eliminate vertical compression forces, prevent the destruction of the sealing of the internal cavities and the violation of the integrity of the cable.
The technical implementation of this method in each specific case requires calculation and justification.
3. Taking protective measures against condensation
Let's say that we have created a house made of laminated veneer lumber, in which we want to preserve the natural color of natural wood and therefore, from the inside, we emphasize its natural appearance with various design techniques. Hidden electrical wiring was placed inside the walls in accordance with all the rules of the PUE, placing it in sealed metal pipes and even provided for devices to compensate for the shrinkage of the building.
If the house is located in a warm area where low temperatures are excluded, then you can calm down on this. When in winter outside the temperature drops to minus 25 degrees or lower, then condensation will appear in the metal pipe with the cable, caused by the temperature difference from the outside and inside of the walls.
Moisture from it will flow from top to bottom to where the sockets and switches are located. With an increase in the thermal drop, its amount will increase. When the minus temperature inside the pipe is reached, the accumulated water will turn into ice.
To prevent the formation of condensation, it will be necessary to apply a layer of thermal insulation on the outside and inside of the wall. How effectively it will start to work remains a question, but the design idea for decorating the walls with natural wood trim will have to be violated.
It remains to consider the option of installing hidden electrical wiring only in internal walls or to think over other technical solutions, for example, placing it in the floor and raising it to a small height to the sockets.
As a result, it turns out that safe hidden electrical wiring can be performed for a wooden house only in compliance with all the requirements of the PUE. However, this will have to provide for the shrinkage of the building and prevent the formation of condensation in the winter.
Violation of any of the above safety requirements, of course, will not immediately lead to a building fire. But the owner must clearly understand that an accident in the electrical circuit can occur at any time. Automatic protections prevent it not instantly, but with the shortest possible time delay. An interruption in the load current is often associated with the formation of an arc, the flame of which is not extinguished immediately.
Dried wood is quite flammable from damage to electrical wiring. To live in a house built in violation of the current rules is to put yourself at risk, to repeat the path of those who have already experienced the consequences of a fire.
The installation of hidden electrical wiring in everyday life, after it has been completed inside the house from any materials, must be inspected and checked by electrical measurements before connecting it under voltage:
for compliance of the assembled circuit with the continuity of the sections of the mounted circuits;
Between all phase and zero wires, as well as to the ground loop.
Without taking measurements, short circuits and leakage currents are possible, which will manifest themselves due to mistakes made immediately when the assembled circuit is turned on under load.
Regardless of what material the walls of the structures are made of, a project is drawn up for all buildings, which indicates the power supply diagram with the locations of all wiring elements:
- Switchboards;
- Junction boxes;
- Socket boxes for sockets and switches;
- Places of installation of lighting devices (chandeliers, shades).
In addition, the power supply diagram indicates:
- Power of circuit breakers on each group in the network;
- Wire type;
- Section of wires;
- Distances between individual wiring elements, between junction boxes, to sockets and switches. From the distribution board to the first junction box and the connection points for high-power household appliances, to which separate lines are laid (heating boilers, electric stoves, pumps, and others).
This information can be used to calculate the required length for each type of wire, taking into account the cross section. The selection of the cross-section of the wires is made according to a separate methodology, which requires detailed consideration, we will proceed from the data specified in the project documentation.
Marks of wires laid in walls
The characteristics of the wires laid along the walls of various structures depend on many factors:
- The functional purpose of the building;
- Equipment operating conditions;
- From the type of building materials from which the walls are built;
- The requirements of the PUE and other guiding documents defining the rules for the installation of electrical installations.
Taking into account these requirements, manufacturers make various brands of wires; PPV is considered one of the most demanded wires by consumers.
PPV -a flat wire, where the conductors are arranged in one row, has an insulation layer on each conductor. The cable is intended for supplying power to socket and lighting networks, withstands voltage up to 450.
It is laid in the walls in residential premises using grades with a cross section of up to 6 mm 2. There are 100 coils in standard packages; 150; 200m, permissible operating temperature from -50 to +70 ̊С.
VVG -the wire has several models, there is a flat design, similar in appearance to PPV, with double insulation.
There are designs of round, square and triangular shapes.
| VVG cables with round conductors | ||||
| Number of cores and nominal cross-section (mm²) | Outer diameter (mm) | Weight of 1 km of cable (kg) | ||
| 660V | 1000V | 660V | 1000V | |
| 2:1,5 | 7,5 | 8,1 | 71 | 80 |
| 2:2,5 | 8,2 | 9,6 | 95 | 116 |
| 3:1,5 | 8,1 | 9,4 | 92 | 116 |
| 3:2,5 | 9,3 | 10,2 | 136 | 150 |
| 4:1,5 | 9,2 | 10,1 | 127 | 142 |
| 4:2,5 | 10,1 | 11,0 | 171 | 186 |
| 4:4 | 11,7 | 13,1 | 243 | 273 |
| 4:6 | 13,1 | 14,1 | 325 | 357 |
Size table of outer diameter and weight of VVG wires
In some products in the insulation there are additives that prevent combustion, such a wire is marked VVGng.
Cable (NYM) NUM -analogue of German wire DIN 57250, flexible, with stranded wires or with rigid monolithic wire, ideal for hidden wiring in walls in residential premises. This is justified by the composition of non-combustible insulation with reduced emission of toxic gases. The round construction has three layers of insulation, on each wire, an intermediate layer of chalk-filled rubber and an outer, non-combustible PVC jacket.
Flat installation wire PUNP -the most common and affordable cable in retail chains. A flat shape with double PVC insulation can have up to 5 wires in the structure.
Tip # 1. Experienced electricians do not recommend using PUNP for wiring, due to poor quality. Statistics show that 60% of fires due to poor-quality wiring occurred in networks with a PUNP wire. 80% of the market is of poor quality products, many manufacturers do not follow the technologies, the discrepancy is revealed in many parameters:
- Insulation thickness and composition;
- Alloy composition of wires;
- Section of veins;
It is safer to buy a more expensive cable and be confident in safety.
Wire selection criteria
First of all, it is necessary to be guided by the project, it also takes into account the brand of the wire and its section, taking into account the operating conditions of the room. In the absence of a suitable wire, its analogue or a product suitable for technical characteristics is installed.
In most cases, PPV can be replaced with VVG, flat wires are often installed under plaster on concrete and brick walls. They reliably adhere to the plane and do not require a thick layer of plaster to hide the network.
Tip # 2 For lighting networks in areas from a junction box to a chandelier or hanging shade, it is recommended to use a flexible stranded wire. At the point where the contacts are attached to the lighting fixture, the chain section is movable and the rigid wires can break off, the flexible ones in this case last much longer.
According to the requirements of the PUE, in rooms with high humidity, wires with rubberized insulation with moisture-proof properties of all elements with a degree of at least IP 54 are installed. As a rule, such wires have a round shape and, before laying, pierce grooves in brick or concrete walls. In wooden log cabins, they fit into a non-combustible corrugated pipe.
For operation in high humidity conditions, wires are used:
- PRHO is laid in non-combustible pipes;
- PRI is a universal wire, can be used in dry and damp conditions.
Laying wires in plasterboard walls
The construction of plasterboard walls provides a large number of screws for fastening various elements. Therefore, special attention is paid to the wiring method, so as not to damage the insulation and not to short-circuit the wires.
Plasterboard sheets are attached to a pre-assembled frame made of galvanized metal guides.
Size table of diameters of plastic corrugated pipes
| Outer surface diameter (mm) | Inner surface diameter (mm) |
| 16,0 | 10,7 |
| 20,0 | 14,1 |
| 25,0 | 18,3 |
| 32,0 | 24,5 |
| 40,0 | 31,5 |
| 50,0 | 39,6 |
For laying wires in such structures, technological holes are provided in the metal profile, the wire must be laid in non-combustible plastic corrugated pipes.
In this case, the places with the sharp ends of the self-tapping screws are bent, before fastening the drywall sheets on the other side of the frame, the cable passage zone is marked, into which the fastening elements are not screwed.
For the installation of socket outlets and junction boxes, holes of the appropriate diameter are drilled with an electric drill with plasterboard crowns. Plastic cups for flush-mounted boxes have a special design with strips that press the case against the wall plane from the inside. To do this, screw the clamping screws clockwise until they stop. Wires are inserted into the technological holes of the socket boxes 15-20 cm to the outside for cutting and connecting sockets and switches.
In the same way, wires are laid and socket boxes are attached in walls made of plywood, chipboard and OSB, in any structures with a hollow interior. For drilling holes in wooden sheets, appropriate crowns and other elements are used.
Laying wires on brick and concrete walls without chipping
In these cases, it is very convenient to use flat wires. Along pre-marked routes, the wire is attached to the walls with plastic clips with heavy-duty nails or plastic dowels from clamps. Previously, the fastening was carried out with tin plates, which were screwed to the wall with self-tapping screws on a plastic dowel or simply shot against the wall with a construction gun.
For socket outlets and junction boxes, holes are drilled with a perforator with special concrete crowns. The body of the socket is inserted into the hole and fixed to the plaster mortar, before that wires are inserted into the side technological holes.
Tip # 3 It is recommended to drill holes for flush mounts after the wall surface with wiring lines is plastered. This technique will ensure the installation of the upper edge of the flush-mounted glass flush with the wall surface.
If you install the socket earlier, it will be difficult to achieve a clear coincidence of levels, and differences lead to problems when installing outlets. With a deeply recessed socket, the bolts for fastening the front panel of the outlet may not reach the thread on the case. With a protruding glass of the socket, there will be a gap between the wall and the front panel.
Junction boxes and socket boxes are manufactured to specific standards. The diameter and depth are selected depending on the size of the switches and sockets; for junction boxes, the number of wires that are inserted into it is taken into account. With a large number of wires with a large cross-section and an outer diameter of a round cable, it is recommended to make grooves in the walls.
Laying strobes in concrete and brick walls
The grooves are punched with a depth of 1-2 cm with a hammer drill in percussion mode with a chisel-shaped attachment. Closer to the sockets and junction boxes, the strobes are made a little deeper, up to 3 cm, so that the wires freely enter the technological holes of the glass of the socket boxes.
Outer diameter and weight of the cable (kg)
| Cross section | Diameter (mm) | Weight of 1 km of cable (kg) |
| 1:16 | 12.3 | 288 |
| 1:25 | 15.3 | 460 |
| 1:35 | 16.5 | 568 |
| 1:50 | 19.0 | 778 |
| 1:70 | 21.8 | 1094 |
| 2:1,5 | 11.2 | 172 |
| 2:2,5 | 12.7 | 224 |
| 3:1,5 | 11.8 | 201 |
| 3:2,5 | 13.4 | 268 |
| 3:1,5+1,5 | 12.7 | 223 |
| 3x2.5 + 1.5 | 15,5 | 350 |
| 3x4 + 2.5 | 16,8 | 437 |
| 3x6 + 4 | 18,5 | 641 |
The width of the groove is made taking into account the number and size of the wires laid in this area.
The wires are fastened in the same way as when laying without strobes. After laying the wires, they are covered with a layer of plaster.
In installation organizations where chasing is performed in large volumes, industrial chasing chasers are used. This tool provides for the adjustment of the depth and width of the chasing; in some models, dust extraction with a vacuum cleaner is provided. The performance of chasing chasers is much higher than when working with a conventional perforator, the channels are smoother, but the price is high, it is not advisable to use it for one-time work.
Tools and nozzles used when laying wires in walls
Grooves and holes for socket boxes can be punched with an ordinary hammer and chisel, but in the 21st century, this is done only with small volumes in the absence of power tools or from scuda, for sports interest.
Puncher is a versatile tool. It can be used as a drill for drilling wood and drywall, in perforation mode, you can drill concrete and brick walls, punch grooves.
Drillswith speed control is used for drilling only wooden and plasterboard surfaces, as a screwdriver with appropriate nozzles. The number of revolutions is set depending on the material being processed, for wood more for metal less.
Attachments for drills and hammer drills are very diverse in design and purpose:
- Conventional drills for wood, metal, with diamond points for drilling concrete and brick;
- Crowns for drilling wood and plasterboard sheets;
- Bits with falfram, diamond and victorious teeth, for drilling brick and concrete walls;
- Falfram-coated titanium tetrahedral bits for screwing in self-tapping screws.
Tip # 4 When buying square bits, do not save on cheap Chinese metal products, they wear out quickly.
Errors when laying wires in walls
- When laying wires in concrete or brick walls without drifting, they forget to make a short strobe near junction boxes or socket boxes. It is imperative that the wires freely enter the technological holes in the lower part of the glass.
If you lead the wire through the top or make a hole in the top, there is a risk of short circuit or breakage. When installing the socket, its body will break the insulation or transmit the wire;
- It is not necessary to install wires on lighting and rosette groups with a larger cross section than indicated in the project, usually 2.5mm 2. With a cross section of 4-6mm 2, the conductors are difficult to place in the contact group of a socket or switch, especially when the alloy is hard and elastic. Sometimes in such cases, contact groups break under the elasticity of the wires, a ceramic or plastic case bursts.
- In order not to be mistaken in the width and depth of the groove in a separate section, fold the width of all the wires that are laid there and make it 1 cm larger with a margin.
- When drilling with a punch with a drywall crown, do not forget to turn off the perforation mode, otherwise the sheet may simply break in this place.
Frequently asked Questions
- In the areas between the junction boxes, the width of the groove turns out to be 10 - 12 cm, I cut the boundaries with a grinder with a disc on concrete, but it is still difficult to knock out the middle part by hand. How to speed up the process?
Cut another line down the center and punch out with a chisel puncher, it will be faster and easier.
- Which wire and switches should be installed in the steam room?
Moisture resistant with rubber insulation NUM or PRI, switches and lampshades with a degree of protection not lower than IP-54;
- Can a flat PPV wire be laid in a bathroom under a layer of plaster and tiles?
It is practically possible and even everything will work, but in order to ensure your own safety and fulfill the requirements of the PUE, it is better to lay NUM or another moisture-resistant cable;
- The electric stove is powered by a copper wire with a cross section of 6mm 2, the main wire between the junction boxes in the socket group is 4mm 2. Can I put a 6 mm 2 wire between the boxes and power the electric stove from the nearest box so as not to pull a separate line?
No, PUE is strictly prohibited, powerful heating devices, electric stoves, heating boilers must be powered from separate lines, through separate machines in the distribution board. In addition, in the option you offer, in addition to the stove, the line will be loaded from the devices connected to the sockets. This could exceed the rated capacity and cause a short circuit and fire.