Any room, regardless of its purpose, can not do without the use of electricity, the arrangement of which involves the presence of numerous switches and sockets. In order for the wiring to be organized correctly, junction boxes are used in which the electrical wires are interconnected in accordance with the diagram. Further cabling is done directly to the connection point of the chandelier, socket or switch.
Purpose and design
A separate cable is never laid from the dashboard (with an electric meter and circuit breakers installed in it) and to each consumer of electricity in the room (apartment, office, store, etc.). In places where it is necessary to equip the branching of wires, junction boxes are installed.
Structurally, such a product consists of a housing and a cover. On the case (depending on the purpose), technological holes are usually provided for the entry of wires and devices for subsequent fastening. The cover is attached to the body with screws, screws or special latches.
Varieties
At the installation site, all junction boxes for electrical wiring are divided into two main classes:
- products for indoor installation;
- for outdoor use.
According to the method of connecting wires inside, such products are divided into:
- boxes without any additional internal devices;
- with integrated clamps, screws or terminals;
- with mounted mount for subsequent mounting of the connection block.
According to the method of installation of junction boxes (depending on the method of arranging the electrical wiring), all products are divided into several groups intended for:
- hidden wiring;
- drywall;
- cable channels.
By geometric configuration, distribution boxes are:
- round;
- square;
- rectangular.
For the manufacture of such devices, mainly various high-strength polymer plastics or (much less often) metal with an anti-corrosion coating are used.
Marking according to international security code
In accordance with international requirements, manufacturers indicate the security code on the box body or in the accompanying documentation. It consists of the Latin letters IP (International Protection) and two digits.
The first digit (from 0 to 6) indicates the degree of protection of the wires inside the box from getting solid objects there. 0 means no protection at all. The numbers from 1 to 4 indicate the maximum size of foreign objects that can get inside through the technological holes (from 50 to 1 mm, respectively). The number 5 indicates that the device is a dustproof design. 6 means the housing is completely dustproof.
The second digit in the marking (from 0 to 8) indicates the protection of internal compounds from the harmful effects of moisture:
- 0 - no moisture protection;
- from 1 to 3 - the design is protected from dripping drops of various intensities;
- from 4 to 6 - the box body can withstand a direct hit of a stream of water;
- 7 and 8 - special boxes that can withstand temporary or prolonged immersion in water.
That is, the higher the number in the marking, the better it is protected. For example, an IP55 distribution box can even be installed in the bathroom. It has a dustproof housing. Cable entries and a sealed cover reliably protect the junction of the wires even from prolonged exposure to a medium-intensity water jet.
Major manufacturers
The most famous and time-tested manufacturers of junction boxes and connection accessories for them today are:
- Russian: TDM Electric, "DKS", Ruvinil, Gusi Electric, "Apis", "Promrukav", "Provento", "Contractor" and "Electropromplast";
- German: Schneider Electric, Rev Ritter and Wago;
- Norwegian Hegel;
- Swiss ABB;
- Turkish: Luxel and Greenel;
- French: Legrand and EKF.
Key selection criteria
Before you purchase a junction box for wires, you need to clearly understand for yourself a few basic nuances. The first aspect of the choice is the type of wiring (hidden, open, in cable channels or behind sheets of drywall). Then you need to determine the number of holes equipped on the case (or easily removable plugs) for inputting wires. And the last one is size. If you plan to connect a sufficiently large number of wires in a junction box, you can not install a small product. Otherwise, the connected ends together with the insulators will simply be impossible to lay inside the housing.
If you still have not picked up a suitable device, then you can connect the junction boxes. The design of some products allows you to do this quite easily: they are simply “fastened” to each other with the help of special protrusions and recesses in the spike-groove system.
For hidden wiring
Despite the complexity of the work, hidden wiring is still the most popular both in the construction of new buildings and in the repair work in apartments. Installation of junction boxes in concrete, brick or building blocks requires the use of special tools and devices:
- punch or powerful electric drill with shock mode;
- special crowns with carbide or diamond tips.
In an equipped hole (with a size slightly larger than the dimensions of the product), such boxes are usually fastened with quick-hardening mortars based on cement or gypsum. The main thing is that after installing the protective cover, the housing is flush with the wall surface. Then the branching point of the wires will be invisible after wallpapering.
Important! Before proceeding with the arrangement of the finish wall covering, it is necessary to draw up a detailed drawing with the location of all the installation locations of the junction boxes. This will greatly simplify the subsequent repair of electrical wiring if necessary.
For open wiring indoors
The easiest way to install the junction box with open wiring. Such products have either special mounting tabs or holes on the back of the case. Enough:
- drill a pair of holes of suitable diameter in a wall or ceiling;
- install dowels in them;
- fasten the box using self-tapping screws.
Special for cable channels
Recently, when arranging electrical wiring in offices, private houses, and sometimes in city apartments, plastic cable channels are increasingly used. This technology has several advantages:
- high speed and low labor input of installation works;
- convenience of subsequent maintenance or repair.
For this method of wiring, special distribution boxes are used. Structurally, they are in many ways similar to products for open wiring. However, their design and colors are best combined with the appearance and color of the cable channels themselves.
For external use
Boxes intended for outdoor installation have specific design features: cable entries are made in the form of tight clamping glands, and the lid is equipped with a special gasket. All this contributes to increased protection of the wires inside the box from moisture. For the manufacture of such products, only impact-resistant plastics, resistant to large temperature extremes, or metal are used. The methods for attaching such devices depend on the wall material.
For drywall
Drywall has been successfully used for a long time for interior finishing works or for the manufacture of interior partitions (both in private houses and in city apartments). Products intended for installation on such walls have their own technological features. In appearance, they resemble standard boxes for hidden wiring. A distinctive feature is the fastening system already installed on the box, which is a long self-tapping screw (or screw) with special expandable petals. Mounting a junction box on a wall or ceiling made of drywall:
- make a hole in the wall that matches the dimensions with the dimensions of the product;
- we drag the wires into the case;
- install the box flush with the surface of the drywall;
- turn the screws or screws one by one until the spacer bars fix the product on the sheet;
- connect the wires;
- install the protective cover.
Methods for connecting electrical wires
To ensure reliable electrical contact, you can use the following methods of connecting wires:
- twisting;
- by welding;
- soldering;
- screw clamps;
- connecting blocks;
- special self-locking terminals.
Welding requires the use of special expensive equipment, therefore it is used mainly in industrial construction. Soldering is much easier even at home, but you must have at least a gas soldering iron (after all, when carrying out such work, the electricity in the house will have to be turned off). The remaining methods are available for independent electrical work and do not require special technical training (of course, with strict observance of all safety measures).
Twist wire connection
One of the most common methods for connecting wires in a junction box is twisting. The popularity of this method is due to the simplicity of its implementation and the sufficient reliability of the electrical contact between the wires. Years of experience have shown that properly performed twisting can properly perform its electrical functions for many decades.
Work procedure:
- we clean the ends of the wires from insulation by 18-19 mm using a special stripper (manual or automatic);
- using pliers tightly twist (clockwise) the stripped ends of the wires;
- put on special plastic caps (with cone springs installed inside), which simultaneously perform three functions: strengthen the mechanical strength of the connection, increase the reliability of electrical contact and provide insulation;
- carefully lay the wires in the box, while not allowing their significant excesses;
Attention! Before connecting the wires in the junction box, it is necessary to disconnect the general power supply of the entire apartment using a knife switch or an automatic machine (usually installed in the switchboard on the landing). Professionals recommend additionally making sure that there is no voltage with a multimeter or a special probe.
Connection of wires with special quick-clamping devices
The German company Wago has developed special quick-clamping devices for connecting wires in a junction box. The convenience of their use was appreciated by both professional electricians and numerous "home craftsmen" who are engaged in arranging electrical wiring independently. The device is a spring linkage mechanism that simultaneously performs two functions:
- connection of electrical wires with a tight and reliable contact;
- highly effective isolation of the junction.
The algorithm for using such devices is simple:
- we clean the end of the wire by 9-10 mm;
- raise the orange lever to the upper position;
- insert the stripped portion of the wire into the hole;
- lower the lever down until it clicks;
- We perform the same operations with all other wires.
The advantages of such devices are:
- convenience, simplicity and high speed of installation;
- high technical characteristics: operating voltage from 220 to 450 volts, current from 20 to 32 amperes;
- universality: depending on the design of the product, 2 to 8 wires with a cross section of 1 to 4 mm² can be connected.
Highly specialized devices
There are a number of highly specialized junction boxes. Such products include:
- special devices for equalizing potentials;
- boxes for branching and connecting computer wires CAT5 and CAT6;
- products for switching telephone wires;
- boxes for branching and connecting fiber optic lines;
- interface splitters.