In most private houses and in almost all apartments, the wiring is hidden. When installing hidden wiring in plastered walls and ceilings, shallow grooves are punched into which electrical wires are laid. After completing the installation of the electrical wiring, the grooves are plastered with cement mortar or alabaster. If the installation of hidden wiring is carried out in a house under construction, then the need for punching furrows disappears. First, the wiring is installed, the wires are fixed with nails driven into the solution between the bricks, or by attaching them to the wall with alabaster at several points, then plastering of the walls and ceiling is done, and the wires are under a layer of plaster.
In the places where the wires are connected, branch boxes are installed, in which all the twists of wires are hidden. The junction boxes should be installed flush with the wall surface, flush with it. The boxes are closed for security reasons and aesthetic plastic lids. The same junction boxes are used to install sockets and switches. They are made of steel or plastic. Sockets and switches are also used for installation in the version for concealed wiring. After installation, they practically do not protrude above the surface of the walls.
For the installation of hidden wiring, copper and aluminum wires in polyvinyl chloride insulation are used, copper – with a cross section of at least 1 mm2, aluminum – at least 2.5 mm2. In apartments, installation of hidden wiring is carried out in channels pre-made in concrete walls and ceilings. Therefore, those living in apartments need to be very careful when switching various electrical wires and replacing switches and sockets. To replace or even grow an electrical wire that you inadvertently broke off, you will have to knock down a tile that you may have recently laid, otherwise you will not get to the place where the wires are connected.
Open wiring is done along the surface of walls and ceilings. For its installation, use copper or aluminum wires with rubber insulation, covered with a layer of polyvinyl chloride. It is also possible for installation to use copper and aluminum wires with insulation from one polyvinyl chloride, but only if the wire has a separating base that separates one core of the wire from another. Electric wires of open wiring are fixed on the walls and ceiling using rollers made of insulating material – porcelain. Each roller has an axis of a hole through which a nail is threaded, securing the roller with wires on it to the wall.
The smallest cross-section of the wire used for mounting open wiring: copper – 1 mm2, aluminum – 2.5 mm2. When installing a horizontal section of wiring along the walls, the wires are laid parallel to the intersection lines of the walls and the ceiling at a distance of at least 100 mm and not more than 200 mm from the ceiling or cornice. The vertical part of the wiring (descents, ascents) is performed perpendicular to the plane of the ceiling. Near doors and windows, the wire is laid at a distance of 100 mm from the edge of the door or window frame. The rollers for fastening the wire are located at a distance of 50 cm from each other.
Switches and sockets with open wiring are not attached directly to the wall surface, but on special insulating pads made of dry wood and called socket boxes. The socket is attached to the wall with a long screw, and a switch or socket is screwed to it with two small screws. The switches and sockets for surface wiring themselves differ from those intended for hidden wiring both in appearance and in the method of mounting on the wall, since due to the specifics of the installation they are located not in the wall, but on its surface. In the basement of the house, due to dangerous conditions (dampness, conductive floors and walls), the switch cannot be installed, it is installed on the kitchen wall. Nowadays, open wiring in houses is rare, but it depends on where. In a house with wooden walls, other wiring is simply impossible.