Schematics for switching incandescent lamps
When installing the lighting device, for safety reasons, it should be remembered that the neutral wire must be connected to the threaded contact of the outlet; the switch must be included in the phase wire. If these rules are followed, accidental contact with the base of the socket (for example, when changing a lamp) will not cause an accident even when the switch is on, since the neutral wire is grounded.
In the switching scheme of an incandescent lamp (Fig. 1, a), the neutral wire N is connected to the lamp 3, and the phase wire Ф to the switch 1. The lamp is connected to the switch with an open wire 2. Until simultaneously turn on several lamps with one switch, the lamps are connected in parallel. The phase voltage is always supplied to the contacts, that is, they must be connected to the phase and neutral wires (Fig. 1, b).
Rice. 1.Schemes for turning on incandescent lamps: a — with one lamp, b — with a lamp and a socket, c — in a chandelier with a double switch, d - in a chandelier with a switch, f — corridor circuit for turning on incandescent lamps
To turn on 2, 3 or 5 lamps, two conventional switches or one switch with two keys are used in the chandelier control circuit (Fig. 1, c). The operation of the chandelier can also be controlled using a brightness switch (Fig. 1, d). In the diagram, the switch is shown in the position where all the lamps are on. If you turn it clockwise, 2 lights will light up, counterclockwise - 3 lights.
For lighting extended rooms with several entrances (galleries, tunnels, long corridors, etc.), the schemes are very convenient, allowing you to turn the lights on and off from several places. In fig. 1, e shows a scheme for controlling a group of lamps from two places using switches. In the figure, they are shown in a position where the lighting is turned off, when you turn each switch 90 °, the lamps light up, and when you turn any of them by 90 °, they go out.
In fig. 2. shows a circuit diagram for turning on incandescent lamps using a single switch.
Rice. 2. Wiring diagram for turning on an incandescent lamp