Replacing ceiling wiring

Anyone who has come across the replacement of electrical wiring in an apartment building knows that the most difficult thing is to replace it in the floor slabs, where it passes to supply voltage to the ceiling lights and chandeliers. This problem does not exist for apartments where there are suspended, stretch and other types of ceilings, in their design between the slab and the decorative plane there is a space in which you can lay wiring anywhere and as you like. But in the case when it is planned to paint the ceiling, glue it on wallpaper or foam tile, this procedure can cause a lot of trouble. There are three types of floor slabs. The first two are constructions with internal channels - voids, where wires of electrical wiring pass, the only difference is that they can go along or across the slab. If you are unlucky, you will have to face a third type, with a P-shaped one, in which there are no voids, and the wires pass under the floor of the upper neighbors,then one way out - to make a false ceiling. In the first two cases, we begin by expanding the hole through which the wire goes to the chandelier. We do this with a perforator, with which we first drill holes with a drill and then with a nozzle - with a chisel we destroy the jumpers.
 replacing the ceiling wiring
Now you need to determine the direction of the channel , as it may be non-perpendicular to the walls. In order to drill control holes in the slab.
 replacing the ceiling wiring
Having determined it, we find the place where the wire exits, it can be in the same room or maybe next door, but always near the junction box, which should be looked for under old plaster and wallpaper.