Flush mounting – design and installation




Author: source: 2021 Installation Guide
Installation of a socket in a recessed installation


In a recessed installation, the cables are routed in sheathing pipes, which are placed entirely under the plaster in grooves cut into the walls of the building. Flush mounting is one of the most labor intensive and costly due to the need to forge grooves along the entire length of the cable route and openings for junction boxes and accessories.

Concealed installation how to design?

Electrical installations in a residential building should be designed and made in accordance with the requirements of regulations and standards, taking into account various technical, operational, economic and other requirements. They mainly stem from the Building Act and its most important implementing decree – the regulation of the Minister of Infrastructure of 12 April 2002 concerning the technical conditions that buildings and their location must meet.

The applicable regulations do not clearly define how the electrical installation in a residential building should be carried out in specific circumstances. The designer therefore has to consider many different factors that influence the correct way to execute it.

Electrical installations in residential buildings can be built-in, built-in or surface-mounted. The following must be taken into account when designing the installation:

  • construction technique, type and size of the designed residential building, as well as the type and properties of the building materials used,
  • type and number of power receivers supplied,
  • environmental conditions,
  • electric shock and fire safety,
  • service security,
  • the ability to perform inspections and repairs,
  • expandable,
  • reliability,
  • installation costs.

Installation of concealed installation

In a recessed installation, the cables are routed in sheathing pipes, which are placed entirely under the plaster in grooves cut into the walls of the building. Flush mounting provides complete protection against mechanical damage and relatively easy replacement of damaged cables.

However, it must be admitted that recessed installations are among the most time consuming and expensive due to the need to forge grooves along the entire length of the cable run and openings for junction boxes and accessories. Therefore, they are most easily applied in relatively soft materials (e.g. aerated concrete).

If this is not possible along the entire route, e.g. with particularly hard materials, or where the concealed installation can weaken the wall structure, it is used in small sections, when it is necessary to limit easy access to wires (e.g. lines ). ).

Plastic installation pipes, both rigid and flexible, are used to create a concealed installation. They are mainly rigid and corrugated flexible wine pipes (the so-called Peschla hose). At the same time, due to ease of use and price, the latter are used much more often.

Single and multi-strand stranded conductors can be laid in the pipes, and their diameters are selected depending on the cross section and the number of conductors to be pulled into them. The relevant tables on the manufacturers’ websites will be helpful here.

Installation of a recessed installation in a residential building requires::

  • routing,
  • forge forward,
  • go through walls and holes for boxes,
  • installation of installation pipes and boxes,
  • wires are pulled in,
  • make electrical connections,
  • mounting accessories,
  • checking the correctness of its operation.

The first step when assembling an electrical installation is always following the route. Designate locations for mounting connectors, wall outlets, lighting outlets, junction boxes, and other accessories, and then route the connection cables.

Of course, the cable routes may be rigidly imposed by the project requirements, then the routing should be carried out in accordance with the construction documentation and electrical installation engineering design, taking into account the building structure and ensuring that there is no collision with others used in the building.

It is also important that there is as little passage through walls and ceilings as possible and that no power cables for other rooms are routed through the bathrooms. Also try to keep the length of the circuits as short as possible, but this should not have a negative influence on the deterioration of the operation of the installation.

Literature:

  1. The Act of 7 July 1994 – Construction Law (i.e. Journal of Laws of 2019, item 1186, as amended).
  2. Regulation of the Minister of Infrastructure of April 12, 2002 on the technical conditions to be met by buildings and their location (ie Journal of Laws of 2019, item 1065, as amended).
  3. W. Dołęga, “Characteristics of electrical installations in residential buildings”, “Elektroinstalator” 2017, no. 6.
  4. W. Dołęga, “Electrical switchboards in residential buildings”, “Electric sector 2016”.
  5. W. Dołęga, “Selected aspects of designing electrical installations in multi-family houses”, “Elektroinstalator”, 2013, no. 6.
  6. S. Kołodziejczyk, “Electrical Installations”, Wydawnictwa Komunikacji i Łączności, Warsaw 2016.
  7. S. Kołodziejczyk, “Installation and maintenance of electrical installations”, Wydawnictwa Komunikacji i Łączności, Warsaw 2017.
  8. H. Markiewicz, “Electrical Installations”, WNT, Warsaw 2014.
  9. S. Nieępski, M. Parol, J. Pasternakiewicz, T. Wiśniewski, “Electrical Installations – Construction, Design and Operation”, Publishing House of the Warsaw University of Technology, Warsaw 2011.
  10. A. Wolski, K. Pazdro, “Electrical Installations in Residential Buildings in Questions and Answers”, WNT, Warsaw 2009.

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