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Installation in a renovated house in plaster - how deep a furrow?

cuma67 26568 14
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Treść została przetłumaczona polish » english Zobacz oryginalną wersję tematu
  • #1 15916948
    cuma67
    Level 9  
    How deep to cut the groove for the cable, eg YDYp 2.5mm square, so that the groove with the cable is not visible on the wall after some time. I found on the net that the cable in the groove must be so laid and that it could be covered with a 5mm layer of plaster, but it is probably not enough, maybe 1cm? I remember that the groove should be primed with Unigrunt - before gluing the groove with the cable laid, e.g. with putty, although I am leaning towards Knauf MP75 plaster. Other advice is, of course, not to buy the cable in DIY stores belonging to large chains, because its external insulation may react with the used mortar and this causes streaks. Still others recommend that when laying the surface, the use of interlining tape, mesh, etc. on the grooves, although I have never encountered this solution in practice. What are your suggestions and tips?
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    #2 15917025
    piotrek22101
    Level 39  
    Hello, as I did four years ago, there is no trace to this day. Depth, centimeter, mesh on top. Then the plasterer covered all the walls with plaster.
  • #3 15917048
    brofran
    Level 41  
    cuma67 wrote:
    I remember that the groove should be primed before sticking, e.g. with putty

    What for ? If it is, then with some UNIGRUNT, so that the putty grips the substrate better.
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  • #4 15918074
    cuma67
    Level 9  
    brofran wrote:
    cuma67 wrote:
    I remember that the groove should be primed before sticking, e.g. with putty

    What for ? If it is, then with some UNIGRUNT, so that the putty grips the substrate better.

    Of course I meant priming with Unigrunt. I improved my post because it was actually understandable.
  • #5 15918407
    jas67
    Level 22  
    If you primer the furrow, you can plug it up with anything. No mesh or fleece. Then smooth it on top and it's good. As for the thickness, I never worried about it, so that only the cable would hide. There has never been a problem and I've been doing it for over 20 years.
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  • #6 15919279
    JohnySpZOO
    Electric installations specialist
    In my company, the wall chaser is set at 2.5 cm. In the previous ones, they furrowed 2-3 cm depending on the number of wires and whether the wires went in conduits.
    The main issue and it would be appropriate to ask what thickness of the plaster layer should cover the cable? And depending on the cross-sections of the cables to be laid, calculate the depth of the furrow.
    It is a good practice for the cable to be covered with a layer of min. 0.5 cm of plaster.
  • #7 15919398
    Łukasz-O
    Admin of electroenergetics
    JohnySpZOO wrote:

    It is a good practice for the cable to be covered with a layer of min. 0.5 cm of plaster.

    Both a good practice and the necessary minimum specified by the law.

    Rozporządzenie Ministra Infrastruktury z dnia 12 kwietnia 2002 r. w sprawie warunków technicznych, jakim powinny odpowiadać budynki i ich usytuowanie wrote:

    § 187. 2. Plug-in electrical cables may be led,
    on condition that they are covered with a layer of plaster of at least 5 mm thickness.


    Unfortunately, this thickness is not always respected (sometimes impossible) and the cables can make themselves felt on a later painted wall or ceiling.
    For the dressing of furrows, no ungrindings are needed. Just wet the furrow with water to get rid of particles and dust.
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  • #8 15919457
    janek1815
    Level 38  
    Łukasz-O wrote:
    wires can make themselves felt on a later painted wall or ceiling.


    My brother-in-law bought a flat in a new condition, less than two years have passed and you can go ahead and drill a drill, you can see exactly how the installation is going. Now he is struggling with the contractor to get them to do something about it.
  • #9 15919587
    JohnySpZOO
    Electric installations specialist
    janek1815 wrote:
    My brother-in-law bought a flat in a new condition, less than two years have passed and you can go ahead and drill a drill, you can see exactly how the installation is going.
    The wires are sweating :D You can tell what method they were laid and what is the thickness of the plaster.

    Łukasz-O wrote:
    Unfortunately, this thickness is not always respected (sometimes impossible) and wires they can make themselves felt on a later painted wall or ceiling .
    Now I am working on the topic in one place where it started to stain after a year - the wires are laid in the groove, covered with about 0.5 cm of plaster and min. 1 cm of plaster (straightened curved walls). Wall painted with unigrunt, 3x Dulux paint with roller.
    What is the cause?
    The reason is the cheapest market wire of unknown origin (there was only 3x2.5mm2 inscription on the insulation) because the owner bought the material (wires) because he thought that he would become the hero of the house.
    What Lord, paint three again.

    I buy cables from TFKable paying a few pennies more and I have not noticed any spotting.

    PS We're a bit off the topic :D
  • #10 16027756
    cuma67
    Level 9  
    Grooves made with a chasing tool in aerated concrete blocks "siporeks". The discs cut like a knife with butter, so the furrow is deep. After laying the cable, there is about 1 cm for the layer of plaster / putty, etc.
  • #11 16029409
    ernest90s
    Level 10  
    Gentlemen, I have been asked about the ELPAR company. Does anyone have experience with these cables? How is the quality and can you see them after some time on the plaster?
    I have put a new installation in my apartment and I am currently at the stage of sealing the furrows. Except that I do it this way, first I put ordinary plaster on the furrows and only then cover it with putty. Of course, before such a procedure, all walls and furrows are dust-free, washed and primed. By the way, I just use plaster to straighten the walls and, unfortunately, some cardboard gypsum boards will be used, because the walls are very crooked here and there (even 2 cm is missing from the vertical). Usually in the middle of the wall height there is the recessed point, as if someone kicked the wall in the middle.
    When it comes to the grooving technique, I cut about 2.5 cm with a wall chaser (I recommend using a vacuum cleaner because without it it is terrible to sneeze) and obligatory glasses, gloves (hot dust, especially in reinforced concrete), earphones (high frequencies, damage to hearing), mask ( for the patient, because the steam from the mouth will steam over the glasses if you furrow the ceiling).
    The wall chaser alone is not enough and you must have a jackhammer, a large flat screwdriver (for breaking furrows, the deeper it is, the easier it is to break it), a chisel with a hammer for small corrections. In addition, you need to cover the windows because if you hit a metal rod, it can result in sparks that will melt into the glass and black dots will appear from pitting. In my case, the bars in the ceiling were shallow, so I had to break off the jumps over the bars, which was a troublesome issue.
    It is worth informing the neighbors, especially if you are furrowing the ceiling, because in my last 2 days there were accusations for application to the cooperative :D
    The jackhammer in particular is annoying.
  • #12 16029464
    Elmont
    Level 26  
    Dear colleague in the slab block has a permit to "pry" the walls from
    cooperatives read real estate managers, what about the construction law .....?
  • #13 16029470
    JohnySpZOO
    Electric installations specialist
    ernest90s wrote:
    Gentlemen, I have been asked about the ELPAR company. Does anyone have experience with these cables? How is the quality and can you see them after some time on the plaster?
    Not with cables, but with wires - the cable is black.
    Like any wire, like a wire, it will sweat unless you lay it deep in the furrow.

    ernest90s wrote:
    By the way, I just use plaster on the walls and, unfortunately, some cardboard gypsum boards, because the walls are very crooked here and there (even 2 cm from the vertical).
    Come to Silesia for a trip - while driving you will see the deviations of some blocks on the facades.
    A friend has recently lived in Chorzów - a deviation from the vertical at a height of 2.4-2.6 m - 30 cm :)
  • #14 16029928
    kosmos99
    Level 38  
    JohnySpZOO wrote:
    I buy cables from TFKable paying a few pennies more and I have not noticed any spotting.


    And this "visibility" of concealed cables is certainly influenced by the insulation of the cables, is it not that the plaster layer is too thin?
    It looks like when there is moisture, it is partially absorbed by the wall, and where the wires (insulation) are, the vapor does not soak up?
  • #15 16938097
    cuma67
    Level 9  
    To sum up, 0.5-1 cm is ok. Proven in practice.

Topic summary

The discussion centers on the appropriate depth for cutting grooves in walls for cable installation, specifically for YDYp 2.5mm² cables, to ensure they remain concealed after plastering. Recommendations vary, with some suggesting a groove depth of 0.5 to 1 cm, while others indicate that 2.5 cm may be necessary depending on the number of cables and their arrangement. Priming the groove with Unigrunt before applying plaster is advised to enhance adhesion. Concerns are raised about the quality of cables from DIY stores, which may lead to visible streaks on walls over time. The use of mesh or interlining tape is debated, with some professionals advocating for their inclusion to prevent future visibility of the cables. Overall, a minimum plaster thickness of 0.5 cm over the cables is emphasized to avoid issues with visibility and moisture absorption.
Summary generated by the language model.
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