Installation of hidden wiring

In the practice of electrical works, hidden electrical wiring is performed by APPVS and APV wires by laying them directly in the thickness of building structures: in plaster, concrete partitions, under plaster, in cavities and channels of ceilings and walls.

Hidden wiring of wires is carried out, observing the following requirements: wires in thin-walled partitions up to 80 mm or under a layer of plaster are laid parallel to architectural and construction lines; the distance between horizontally laid wires and floor plates should not exceed 150 mm; in building structures with a thickness of more than 80 mm, the wires are laid along the shortest routes.

In the premises of brick buildings, as well as in large block buildings with partitions of small plates, hidden wiring with flat wires is carried out as follows: in brick and plastered walls - directly under a layer of plaster; in walls of large concrete blocks — in the seams between blocks and individual sections in channels; in slab ceilings with tiles — in slab cavities.

The installation of electrical wiring begins after the completion of construction work and work on laying a clean floor.

The installation of hidden electrical wiring is carried out in a certain sequence.

First, they mark the wiring route, determine the places for installing junction boxes for switches and sockets, hooks for lamps. Marking begins with determining the places for installing shields, lamps, switches and sockets according to the project.

Then mark the wire traces. The flat wires are laid at a distance of 100 — 150 mm from the ceiling or 50 — 100 mm from a beam or cornice. The wires can be laid in the slots between the partition and the ceiling or beam. The lines to the contacts are laid at the height of their installation (800 or 300 mm from the floor) or in the corner between the partition and the upper part of the floor plate. Descents and ascents to switches, lamps are performed vertically.

When laying wires and cables in channels of prefabricated building structures, marking of routes and places for installation of devices is not required.

Before tightening the wires with a pressure gauge, check the suitability of the channels. The diameter of the gauge must be at least 0.9 of the design diameter of the channel. Particular attention is paid to the presence of swellings and sharp edges at the junctions of the construction elements of the buildings.

Then check the condition of the connecting niches of adjacent connecting panels. The niche is made of a semicircular shape with a radius of 70 mm. wires are drawn into the channels from the device to boxes and niches. The clamping force should not exceed 20 N per 1 sq. Mm of the total cross-section of the wires.With a channel diameter of 20 mm, you can tighten up to 5 wires, with a cross section of 25 mm — up to 8 wires with a cross section of 205 mm square.

With a limited number of wires and a short length of the channel, tightening is done manually, with a large number - with the help of steel wire pre-tensioned in the channel.