Sockets and switches have a special terminal for connecting them to the wiring. Assemble them before they set in a box, to this end and leave a long enough cable ends, releasing them through the assembly window boxes. Special care needs cleaning operation (cutting) end of the cable. First you need a sharp knife make an incision mounting along the outer sheath, taking care not to damage the insulation of wires. The length of the incision chosen to ensure the wire to be connected to the most remote terminal. Then incised part of the shell to bend, releasing core, and cut.
The most convenient way to butcher the cable brand NYM: their outer shell is a tube, not related to veins, and separated from them by not transmitting burning soft and fragile strip, therefore a danger to penetrate the insulation had lived at cutting through the shell is small. After liberation, he lived each one of them cut to length, based on the location of the terminals, and smooth out the insulation of each wire, leaving a bare end length of 6-12 mm (to the edge of isolation after connecting the wires came as close as possible to the terminal). Most responsible operation – trimming the ends of living, especially aluminum. Often do so: with a knife in the right place doing the annular incision in the insulation of wire and dragged the end of the conduit. At the same time inevitably remains circular scratch on aluminum or copper conductor.