How to connect a pass switch to control the light from 3 places
Often there is a need to control lighting from several points spaced apart in space. In many cases, several remote controls located in different places can help out. But this method is not always applicable, and has its disadvantages. For example, in the form of the need to periodically replace batteries that are discharged at the most inopportune moment. Therefore, the classic solution with wall switches has solid preferences.
Examples of light control from three points
Such a scheme can be useful in T-shaped aisles and corridors. When entering anywhere, you can turn on the light, when leaving - turn it off, regardless of the direction of movement. Also, a similar system can be useful in bedrooms or in children's rooms for two people. The switch at the door turns on the lighting, at each bed it turns off.Or vice versa - getting out of bed, you can turn on the light, and leaving the room - turn it off.
If there is a staircase consisting of two spans, then a similar principle can also be implemented on it. Lights can be turned on and off from below, above and between spans. There may also be other situations where such a scheme can be beneficial - it is impossible to predict all cases.
Applied switching devices
To create a lighting switch circuit from 3 places, you need to use three light switches that look like ordinary ones. The differences are within.
Through-hole device
To build a given lighting system, you will need a single-gang switch. It looks the same as the standard one, but is often marked with a flight of stairs or arrows, although not always. Not all manufacturers, including the world leaders in electrical engineering, bother applying additional badges. Because international standards do not require it.
The main differences are inside the device. They can be seen immediately - instead of the usual two terminals, the pass-through device has three.
This is due to the difference in the design of the contact group of such a switching device. Instead of two contacts for closing / opening, it has a changeover group for switching. In one position, one circuit is closed, the other is open. In the other, the opposite is true.
Pass-through devices are also available in two- and three-key versions.In this case, they control two and three groups of switching contacts. This property of such switching elements is used to build independent light control circuits from different points. Using two such devices, you can turn on and off the lamps from two places.
Cross type instrument
To build an independent control circuit from three points, you will need another type of switch - a cross (sometimes called reversing). Marking for it is not provided, so from the front side it cannot be distinguished from the usual one.
Like the previous case, all the differences are inside the device and are visually noticeable from the back side - such a device has four terminals and two changeover contact groups.
The circuit of any cross switch is assembled as follows:
- changeover contacts are free and brought to separate terminals;
- the normally open contact of one group is connected to the normally closed contact of the other group, the connection point is brought out to the terminal;
- the normally closed contact of one group is connected to the normally open contact of the other group, the connection point is brought out to the terminal.
If we analyze the operation of such a switch, the origin of the term "reversible" becomes clear - it can be used to change the polarity of the DC voltage, which reverses, for example, the direction of rotation of a DC motor. To build a lighting system with three-point control, you need one such apparatus.
Just like conventional devices, walk-through and cross switches are surface-mounted and internal. The first are mounted on a plane, the second - in a specially equipped recess in the wall.
Three-place lighting control scheme
With the help of two passing elements and one cross, it is possible to build a scheme for switching on and off lighting from three places spaced apart in space.
All devices are connected in series to break the phase of the lamp power circuit. Obviously, each switch individually can assemble a circuit or turn off the voltage by transferring to the opposite state, regardless of the position of the other switching elements.
Materials and tools for arranging the control circuit
First of all, you need to decide on the topology of laying cables and lighting wires. Since all switches are connected successively, it makes sense to lay conductors in a loop without using junction boxes. This option is suitable for both hidden and open wiring.
You will need a cable with a cross section of 1.5 sq. mm:
- of two cores from the switchboard to the first pass-through switch;
- three-core from the first through to the cross;
- three-core from cross to the second through;
- two cores from the second cross to the lamp (group of lamps).
In this embodiment, the neutral wire goes along with the phase wire along the entire length of the wiring. The disadvantage of this solution is the need to connect the neutral conductor at several points, which is undesirable for safety reasons - the probability of a zero break due to a multitude of terminal blocks or twists increases.You can lay this line with a separate wire directly from the switchboard to the lamp, then the number of cores in each segment will decrease by one.
If you cannot do without arranging a junction box or the control circuit is built into an existing lighting system, the gasket can be done differently.
Galvanically, this circuit does not differ from the previous one and works similarly. The connection of the first and last switch is made to the break of the phase wire in the box.
| Cable | Core material | Number of cores | Additional properties |
| VVG 1x1.5 | copper | 1 | |
| VVGng 2 x 1.5 | copper | 2 | Incombustible |
| VVG 2 x 1.5 | copper | 2 | |
| NYY-J 3x1.5 | copper | 3 | |
| VVG 3x1.5 | copper | 3 |
The names of some cables suitable for use in the arrangement of the circuit are given in the table.
Mounting switches
If the type of wiring is selected, cables with the required number of cores are laid and socket boxes are equipped with hidden wiring, linings are mounted with open wiring, then you can proceed directly to installation of switches. To do this, you need tools:
- pliers for shortening conductors;
- fitter's knife or insulation stripper for stripping the ends of the cores;
- a set of screwdrivers for tightening the terminals, screwing in the fastening hardware and tightening the expanding lugs.
You may also need other small tools.
Important! Any installation must begin with turning off the voltage in the switchboard and checking the absence of voltage directly at the work site (with a multimeter, an indicator screwdriver or a low voltage indicator).
The first pass-through device can be installed on the first floor of the house at the front door, the second - on the second at the flight of stairs, the third - on the third, also not far from the stairs. Then there is an opportunity, entering the house, turn on the light, and having risen to the desired floor, turn it off. In addition to the switches, such a circuit will require a cable for laying the wiring connecting the switches.
First you need to partially disassemble the switch - remove the key and the decorative frame.
Next, you need to shorten the conductors sticking out of the wall to a reasonable length - so that when you install the switch, they are completely removed into the recess.
The shortened cores must be stripped by 1-1.5 cm, inserted into the terminals of the electrical appliance and clamped securely.
Next, the device must be carefully installed in the place intended for it and fixed according to its design.
Some types of devices require fixing the metal frame with self-tapping screws, some require opening the petals. There are devices in which both types of fastening are combined. After that, you can put on a decorative frame, set the key and move on to the next electrical appliance. The cross switching element is mounted in the same way as the 3-point feed-through switch, but 4 conductors are suitable for it - two on each side.
After completing the installation work, you can apply voltage to the control circuit and test it in operation.
Video lesson: Connecting a through and cross switch, designed to control lighting from three or more points.
Possible mistakes
With a careful approach to installation, the probability of errors is small.But you can still mix up the type of switches when buying. It is necessary to carefully read the technical specification for the devices and pay attention to the back part - a connection diagram is often applied there.
In order to minimize errors during installation, before starting work, it is advisable to make a sketch of the wiring diagram for the feed-through and cross switches from 3 places with the designations of the terminals of the devices. If cables with colored or numbered cores are used (and this will greatly simplify the work), colors or numbering should also be applied to the sketch. If the cores do not have a factory marking, you will have to call each conductor and put a designation on it (in the form of several stripes or dots with a marker, fixing a tag with an inscription, etc.). It also does not hurt to mark on the diagram each mounted and tested circuit.
It is easy to install and connect a three-point independent light control system. It is only necessary to carefully study the material part, its principle of operation and reduce to zero the likelihood of errors in installation before the first start.