How to choose a pass-through switch: device and appointment of various types + marking
To control the lighting devices on the stairs or in a long corridor, the usual scheme with one “on / off” device is not suitable. To turn off the light in such a situation, you have to go back to the only switch in the room.
Here, a practical switch is more practical, allowing control of light bulbs from two places. Such a device is more difficult to mount, but it is much more convenient to use.
Instrument selection: switches vs switches
Before you go to the store lighting for the necessary materials, you first need to understand the terminology and various devices switching electricity.
For most novice electricians, that switch, that switch is one and the same. However, they only look like each other.According to the principle of operation, these devices differ dramatically.
A conventional "SWITCH" is the simplest breaker / short circuit key. It has one incoming and one outgoing wire. Plus there are two- and three-key devices with a large number of contacts. However, it is just two or three assembled together in a single switch box.
A “SWITCH” is a switching device in which one incoming electrical circuit switches to one of several output circuits. Often, such a device is also called a “toggle switch”, since it has a key for transferring contacts from one position to another.
At a minimum, in such a single-key device there are three contacts (one incoming and one pair). If there are two keys, then there are already six terminals (a pair at the input and four at the output).
The term "ACCESS SWITCH" means several switches interconnected according to a specific scheme.Such a switch is designed to turn on / off a single light source from several points in a room or a fenced area with lighting at once.
As a result, a two-contact switch is designed to break one electrical circuit with a phase through which the light bulb is powered. A three-prong switch is used to create new individual power circuits. The first option is needed to stop the supply of current through any circuit, and the second - to switch between circuits.
Outwardly, both devices look exactly the same. This is a case with one or more keys. In this case, the switch can be used in the switch mode, but not vice versa. It is impossible to make a three-contact device from a two-contact device. But to exclude the use of one of the chains is quite acceptable. But to organize the management of light from several points, you only need to buy switching devices with three or more contacts.
Types of household switching devices
Switches arepush buttons,keyboardsandswivel. The first option is usually used only as a bell at the front door. It is not suitable for controlling lighting. But the second type for turning on / off the light in a residential building is just what you need. The rotary version is more intended for production and utility rooms. These products are not very presentable appearance.
By the number of keys switches are:
- single key;
They are divided intoordinary(walkthroughs),combinedandcross(intermediate). The first have three contacts. In the second, this triple of terminals is increased by multiplying by the number of keys. And at the third entrances and exits on two. The latter are intended for circuits not with two, but with several points of switching on the light.
Under the scheme for the supply of wires switches are foropen(invoices) andhidden(built-in analogues)wiring. The first are mounted on the wall with dowel-screws, and the second are fixed in podrozetniki using expanding legs.
When selecting switches for connection according to the circuit-breaker circuit, it is necessary to correctly select the number of keys (one for each connected group). If there are two control points in the plans, then only a pair of ordinary three-contact devices will be required. If you need more of these points, then for each such place to be included in a single system, you will have to additionally take an intermediate cross unit.
In most cases, the key of the household switch has two positions for closing one of the circuits. But there are also modifications with zero middle state. In this position, both contours are broken.
Marking on the switch housing
On the part of the switch where the contacts are located, there is usually a special marking indicating the characteristics of the switching product. At a minimum, this is the rated voltage and current, as well as the degree of protection by IP and the designation of terminals for wires.
When you turn on the light in fluorescent lamps in the circuit there is a sharp surge of starting current. If LED or incandescent bulbs are used, this jump is not so big. Otherwise, the switch should be designed for such high loads, otherwise there is a risk of contacts burning in its terminals. That is why it is so important for fluorescent light bulbs to choose special switches.
For installation in the bedroom or corridor, a switch with IP03 is quite suitable. For bathrooms, it is better to raise the second digit to 4 or 5. And if the switching product is installed on the street, the degree of protection should not be lower than IP55.
Contact clips for electrical wires on the switch can be:
- screw with pressure plate and without it;
- screwless spring.
The first are more reliable, and the second greatly simplify the implementation of electrical installation. Moreover, the best option is screw clips with the addition of a pressure plate. When tightening, they do not destroy the core of the wire with the tip of a screw.
Also in the labeling of the switches there are terminal symbols:
- "N" - for the zero working conductor.
- "L" - for the conductor with the phase.
- "GROUND" - for the protective conductor, which is zero for grounding.
Plus, usually with the help of "I" and "O" indicates the position of the key in the modes "ON" and "OFF". More on the case may be the manufacturer's logos and product names.
Lighting control from multiple locations
There are several schemes for mounting switches for switching on the light from different ends of the corridor. The simplest of them implies the presence of the keys of switches in two distant places of the room and one power line of the lamps. If it is necessary to make more than two switching points for lighting, then the wiring of electric wires will come out a little more difficult. But there is nothing special wise here either.
If it is planned to apply a voltage to a chandelier with two or three separate sets of light bulbs using a pass-through switch, the circuit will become somewhat more complicated.Here it is necessary to mount switches with several keys, and there are much more terminals for wires there.
Scheme # 1: to turn on the light from two points
The easiest way to organize the management of the lighting device from two different places in the room. All you need is a pair of standard switches and a few meters of electrical wiring. Plus, you will need to follow the simplest rules of wiring to eliminate electric shock and guarantee the safety of operation of the entire system in the future.
When implementing such a wiring, the output of both switches are connected by a pair of cores to obtain two separate supply circuits. Then a wire with a phase is connected to the input of one switching product, and a branch to the light bulb is connected to the input of the second one.
As a result, at any position of both keys, the common power circuit of the “feed-through switch” will turn out to be either broken or connected. The light can be turned on and off from two different points.This solution allows you to power up the lighting device when you turn on only one key. The second, on the other side of the room, always commutes one of the existing lines.
Scheme # 2: for two lamps
The first scheme is the simplest and cheapest to implement. It is used most often. However, if there are several luminaries in the room or light bulbs in the chandelier are divided into two groups, then this variant of the walk-through switch will not work.
According to the technology of installation and the devices used, this scheme practically repeats the first basic version. Only wires in this case will have to lay more. And in order to save at least a little on them, it is recommended to make the power cord to the first switch in the circuit with a jumper. Pull a couple of individual cores from the junction box will be too expensive.
If there are three lines with lamps, then the two-button switches are changed to three-button analogs.In all other respects, the wire connection scheme remains the same, only their number increases.
Scheme # 3: for multiple switches
With two points of inclusion of light and one or several groups of lighting, everything is quite simple. They need wiring and a pair of switches. But if necessary, to organize the management of several places will have to acquire another type of switching devices.
In such a scheme, the extreme switches are placed with the usual walkthroughs, as in the first case. And between them is then mounted cross analog with four terminals connecting the electrical wiring. When you press a key in such a switching device, the connected contacts open and immediately cross-lock them into a new supply circuit.
In addition to single-key cross-switches, there are devices with a large number of keys. They are intended for circuits with several groups of light bulbs.However, in this case, the lived to the terminals would have to be connected much more. And here it is extremely important not to mess up anything. For proper wiring with such a wiring should be monitored very carefully.
Electricians recommend connecting switches to each other through a junction box. However, it is much easier to do this directly through a twin wire.
Practice shows that such a connection is more appropriate and does not violate the norms of electrical engineering. And the consumption of electricity with him is reduced seriously.
Conclusions and useful video on the topic
There are a few nuances of connecting the switches so that the lighting can be controlled from several points. But they are. And to miss them out of ignorance of their appearance when performing installation is impossible. To make it easier for you to understand all the intricacies of the schemes described above, we recommend that you definitely watch the video below.
All about pass-through switches - principles of operation and installation:
How to connect a two-button switch:
The wiring diagram of the loop-through switches through the junction box:
Using pass-through switches greatly simplifies the control of lighting in a large room, making this process more convenient. Self-mount such a system of several switches and wires is easy. It is only necessary to choose the right set of necessary switching devices.