Any room, regardless of its purpose, cannot 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, the cabling is carried out directly to the place where the chandelier, socket or switch is connected.
Purpose and design
From the shield (with an electric meter and overload or short circuit protection circuit breakers installed in it), a separate cable is never laid to each consumer of electricity in the room (apartment, office, store, and so on). In places where it is necessary to equip the branching of wires, junction boxes are installed.
Structurally, such a product consists of a body and a cover. On the body (depending on the purpose), technological holes are usually provided for the input of wires and devices for subsequent fastening. The cover is attached to the case using self-tapping screws, screws or special latches.
Varieties
According to the installation site, all electrical wiring junction boxes are divided into two main classes:
- indoor products;
- for outdoor use.
According to the method of connecting wires inside, such products are divided into:
- boxes without any additional internal fittings;
- with built-in clips, screws or terminals;
with installed mount for subsequent mounting of the connection block
According to the method of mounting junction boxes (depending on the method of arranging electrical wiring), all products are divided into several groups designed for:
open wiring;
- hidden wiring;
- drywall;
- cable-channels.
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.
Marked 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 Latin letters IP (InternationalProtection) and two digits.
The first digit (from 0 to 6) indicates the degree of protection of the wires inside the box from the ingress of solid objects. 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 case is completely dustproof.
The second digit in the marking (from 0 to 8) indicates the protection of internal connections from the harmful effects of moisture:
- 0 - no moisture protection;
- from 1 to 3 - the design is protected from drops of varying intensity;
- 4 to 6 - the body of the box can withstand a direct hit by a jet of water;
- 7 and 8 are 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 junction box can be installed even in a bathroom. It has a dustproof housing. Cable glands and a sealed cover reliably protect wire connections even from prolonged exposure to a medium-intensity water jet.
Main producers
The most famous and time-tested manufacturers of junction boxes and connecting 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.
Main selection criteria
Before you purchase a junction box for wires, you need to clearly understand a few basic nuances for yourself. The first aspect of the choice is the type of wiring (concealed, open, in cable channels or behind drywall sheets). Then you need to determine the number of holes equipped on the body (or easily removed plugs) for entering wires. And the last one is the size. If you plan to connect a sufficiently large number of wires in the junction box, then you can not install a small product. Otherwise, the connected ends, together with insulators, will simply not be able to be laid inside the case.
If you still haven't found 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 according to the “thorn-groove” system.
For concealed wiring
Despite the laboriousness of the work, concealed wiring is still the most popular both in the construction of new buildings and in renovation work in apartments. Installation of junction boxes in concrete walls,bricks or building blocks requires the use of special tools and fixtures:
- hammer drill or powerful electric drill with impact mode;
- special hole saws with carbide or diamond tips.
In the equipped hole (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 finishing 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 exposed indoor wiring
The junction box is most easily installed with open wiring. Such products have either special mounting protrusions or holes on the back of the case. Enough:
- drill a couple of holes of suitable diameter in the wall or ceiling;
- install dowels in them;
- fix the box with screws.
Special for cable ducts
Recently, when arranging electrical wiring in offices, private homes, and sometimes in city apartments, plastic cable channels are increasingly being used. This technology has somemerit:
- high speed and low labor intensity of installation works;
- Ease 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 color schemes are best combined with the appearance and color of the cable channels themselves.
For external use
Boxes designed for outdoor installation have specific design features: cable entries are made in the form of tight clamping glands, and the cover 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 that are resistant to large temperature changes, or metal are used. The methods of fixing such devices depend on the material of the wall.
For drywall
Drywall has long been successfully used for interior finishing work or 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 mounting system already installed on the box, which is a long self-tapping screws (or screws) with specialexpanding petals. Mounting the junction box on a plasterboard wall or ceiling:
- make a hole in the wall that matches the dimensions of the product;
- dragging the wires inside the case;
- install the box flush with the drywall surface;
- alternately tighten the screws or screws until the spacer bars fix the product on the sheet;
- connect wires;
- install protective cover.
Methods of connecting electrical wires
To ensure reliable electrical contact, you can use the following wire connection methods:
- twisted;
- welding;
- soldering;
- screw terminals;
- connecting blocks;
- special self-clamping terminals.
Welding requires the use of special expensive equipment, so 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 rest of the methods are available for independent electrical work and do not require special technical training (naturally, with strict observance of all safety measures).
Twisting wires
One of the most common ways to connect wires in a junction box is twisting. The popularity of this method is due to the simplicity of its implementation andsufficient reliability of electrical contact between the wires. Many years of application experience has shown that properly performed twisting can properly perform its electrical functions for many decades.
Work order:
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;
- we put on special plastic caps (with conical springs installed inside), which simultaneously perform three functions: increase the mechanical strength of the connection, increase the reliability of electrical contact and provide insulation;
- carefully lay the wires in the box, while avoiding their significant bends;
install the cover
Attention! Before connecting the wires in the junction box, it is necessary to turn off the general power supply of the entire apartment using a knife switch or 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.
Connecting wires with special quick clamps
The German company Wago has developed special quick-clampingdevices 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 on their own. The device is a spring-loaded lever mechanism that performs two functions simultaneously:
- connecting electrical wires to ensure tight and reliable contact;
- Highly effective junction insulation.
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 top position;
- insert the stripped section of wire into the hole;
- lower the lever down until it clicks;
- do the same operations with all other wires.
The advantages of such devices are:
- convenience, simplicity and high speed of installation;
- high specifications: operating voltage from 220 to 450 volts, current from 20 to 32 amps;
- versatility: depending on the design of the product, from 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. These items include:
- special equipment for potential equalization;
- 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.
