One of the main difficulties arising in the process of installing electrical wiring with their own hands is the need to connect the wires in the junction box for electrical wiring. In order to prevent common mistakes, and, as a result, malfunction of switches or sockets, consider each stage of the independent work.
What is an electrical junction box for?
Virtually every person, one way or another, has an idea of what a junction box looks like. But here about why it is really needed, and how it is arranged, not everyone knows. Consider the general data that we know about this element of the wiring.
Junction boxes differ depending on their shape, as well as the characteristics of the application. Some of them are rectangular and some are round. This parameter does not affect the functionality.
As for the features of the application, there are distinguished:
- flush-mounted junction boxes;
- junction boxes for open wiring.
They differ from each other by fastening method, some features of the device, and in some cases by size. In any case, they have one single purpose – the separation of wires from the panel to separately located points of energy consumption, for example, switches, lamps, sockets. In this case, the distribution of electricity should be uniform to avoid disruptions in the operation of devices.
To achieve this goal, the wiring is divided into separate lines or so-called groups. Separate wires are laid in each room that will power the devices, ensuring their operation. It is at this stage that junction boxes appear. They are installed in the nodal points where the wires are interconnected.
To buy a junction box for electrical wiring is necessary, first of all, for reasons of fire safety. So how exactly at the junction of the wires the risk of the source of fire is greatest. If the contact is broken, the resistance increases and the connection begins to heat up. In some cases, this may cause a fire.
External distribution electrical boxes serve as an insulating layer between a potential source of ignition and surrounding objects. In addition, they have a significant aesthetic role, hiding not always beautiful connections of wires from the eyes.
Some argue that the presence of junction boxes in the house is not necessary. But in fact, in order to do without them, it is necessary to lay a separate wire from the panel to each place of electricity consumption. To do this, you need to make a set of sufficiently deep and wide gates in the wall in order to lay wires in several rows. All this entails additional costs of finance and effort.
If, in case of refusal to use junction boxes, to be guided by the fact that the laying of individual wires eliminates the presence of connections in the wiring at all, and therefore is safer, then there is a good answer from the experts. Connection of wires, carried out in accordance with all standards and the scheme of connection of wires in the junction box, is not dangerous. In any case, you can always ask for help from specialists.
Each mounting junction box has a number of its characteristics, among which size and price play a special role. Consider the three most popular options that are usually set in residential buildings:
- Distribution box 100x100x50 mm IP54.
- Distributive box of 80х80х40 mm for external installation of IP55.
- Distribution box IP65 88x88x53 mm.
The first option – one of the most affordable and at the same time common. For example, a Tyco junction box can be purchased for as little as 50 rubles. Its low cost is due to domestic production, as well as the minimum configuration (body and cover).
The second option also has a minimum cost – 46 rubles. It is made of propylene and LDPE. Of course, it cannot be said that he will ever be able to compete with metal distribution boxes, but he more than fulfills his function of protecting wires from precipitation and wind.
The third option, made in Germany, will cost you a little more, about 211 rubles. In this case, the characteristics and dimensions of the junction box are not much different from the first two options. However, according to the manufacturer Hensel, plastic, which is used for the manufacture of their products, is of very high quality and meets all the requirements for electrical wiring elements.
Of course, all this is quite simple and cheap options. Electrical junction boxes with terminals cost much more. But here we can say that their price is justified by the ease of connecting the wires and their further maintenance.
Helpful advice! If you do not want to save on security, you should consider purchasing an explosion-proof junction box.
Terminals occupy a special place in the arrangement of electrical wiring. Installing a junction box of this type is the most simple and does not require special skills. The bottom line is that the box is already equipped with special clips that are designed to connect wires. Compared to conventional, such junction boxes have a number of advantages:
- assembly and disassembly of conductors is carried out several times faster, without the need to use any additional tools;
- thanks to the use of special paste, you can interconnect the wires from different materials, for example, copper and aluminum;
- a special wire placement system helps maintain order in the box, which reduces the risk of a short circuit to zero;
- The special design makes it easy to measure current without the need to remove insulating materials from wires and does not affect the integrity of the system at all.
For open wiring, junction boxes of this type have become the most popular option. After all, the absence of the need to self-twist and connect the wires made the use of terminals very convenient. Today there are many different options on sale, including an explosion-proof terminal box.
It is generally recognized that good contact is the result of proper connection of the wires to each other. If the work was not performed with sufficient quality, it will immediately become noticeable due to weak contact or its complete absence. In addition, problems may arise at the moment when you plug in a sufficiently powerful device.
All this, of course, delivers a lot of discomfort. And it is much easier to take care of this in advance, even at the stage of installing electrical wiring, than to try to solve this problem over time. Consider the most popular ways to connect the wires to each other:
- twisting the wires in the junction box;
- pressure testing;
- welding;
- spike;
- use of screw terminals;
- bolted connections;
- self-tightening.
All these methods are simple enough to implement and do not require special skills. Let’s take a closer look at each of them in order to get an idea of how best to connect the wires in the junction box.
In order to independently carry out all the work correctly, you should consider only one main requirement that applies to the installation of junction boxes: it is necessary to provide free access to all wiring points. This is necessary in case of failure of one of the sockets or switch.
Note! If during initial installation the junction box is hidden behind the finishing coating, then at the first malfunction it is necessary to completely remove it in order to carry out repairs.
Not always the problem may be hiding there, but it will never be superfluous to check the presence of a contact. Therefore, think over everything in advance so that any repairs can be carried out as quickly and easily as possible. In this case, the connection of wires in the junction box can be made in any way convenient for you, which will be discussed below.
Almost everyone knows how to twist the cleaned tips of the wires. However, if we are talking about connecting the wires in the junction box, it is worth recalling the regulatory documents that cover this issue.
Stranding is considered an unreliable connection option, since the contact area is very small, and you cannot count on full contact between the wires. In addition, over time, even this small contact tends to weaken, which makes it impossible to use powerful instruments that give a serious load to the system.
Crimping is considered to be a more reliable method, for which a special connecting sleeve is used. The main parameter of her choice is the thickness of all the wires that will be placed into it. Both copper and aluminum can be the material of manufacture, and the choice depends on what material the wires are made of.
In order to ensure fixation, use a special tool with which the sleeve is compressed. This can be done only with a press tong. To use for this passatizhi categorically not recommended. Otherwise, this technology fully complies with all the norms and requirements stipulated by regulatory documentation.
Here is how the wires are connected in this way:
- insulation is stripped from the wires taking into account the required length, that is, the length of the sleeve used;
- stripped tips of wires twisted and inserted into the sleeve;
- with the help of press jaws the sleeve is crimped;
- With the help of electrical tape or heat shrinkage, the junction is insulated.
This method is considered to be very reliable, since as a result of the work a single whole wire is obtained, which is practically not susceptible to oxidation. By melting the wires together, you get a reliable contact that will not weaken over time. However, the implementation of this method is a little more difficult than the previous one, because you need welding equipment and the ability to handle it.
The list of tools that are necessary for welding wire:
- welding machine with a capacity of at least 1 kW and calculated for 24 W;
- carbon electrode;
- rosin or flux, which will provide further protection of the metal part of the wires from oxidation;
- personal protective equipment: glasses and gloves for welding.
If you have at least the minimum skills with a welding machine, as well as all the above components, the further stages of work will not be of particular difficulty for you. The wires are cleaned from the insulation, and their interior is cleaned with sandpaper to shine.
After that, twist the wires in the traditional way and pour the flux into the recess of the electrode. Press the wires to it and hold until you see the appearance of a ball, the so-called contact point. After that, the process of connecting the wires can be considered complete. It remains only to clean the junction of excess flux, varnish and insulate.
At first glance, this method is similar to the welding method, but it has a significant difference. For soldering wires together, solder is used, melted by a soldering iron. This is an approved method that provides a reliable connection. Its only drawback is that it is not very reliable in places where wires are subject to strong heating.
Note! If you do not know how to solder, then this method is best not to use. The connection may turn out to be too brittle, and at the slightest mechanical load or tension the wires may simply break in the place of adhesion.
In order to solder the wires you will need:
- soldering iron;
- tin-lead solder;
- rosin or flux;
- in the case of using flux – a special brush for it;
- fine sandpaper.
For the most part, the process of connecting the wires is the same as in the case of welding. However, it is not the metal itself that melts, but only the solder. In this case, you need to carefully monitor that the molten solder necessarily flows into the inside of the twist for more reliable bonding. For the most part, this method is used to work with copper wires, however, subject to the availability of special solder, the same can be done with aluminum.
The use of screw terminals is a fairly common method used by many, because of its simplicity and convenience. However, it also has its drawbacks, which is useful to know before starting work.
Initially, screw clamps were used to interconnect various metals that should not touch. For example, it could be copper and aluminum, which in the presence of moisture begin to interact with each other. Over time, this method began to be used for connecting wires. And even was fixed at the level of regulatory documentation.
Note! When using this method for aluminum wires, you need to know that they will require periodic crimping so that contact does not get lost and does not weaken over time.
Bolted connections are also often used to connect wires, however, if it is a question of hiding them after that in a junction box, then this method can be considered inappropriate. It’s all about the bulkiness of connections.
In order to connect the wires in this way, you need to insert a steel washer between them. This happens in the following sequence: a washer is put on the bolt, then one of the wires is put on, and then another washer. This is followed by a second wire and a nut, which tightens the system. Of course, all this also requires good insulation, so the volume of the connection is decent.
Helpful advice! This method has its advantages – it is well suited for the connection of different metals, as inside you can put a special paste that prevents oxidation processes.
Having dealt with the ways in which wires can be fastened together, let us consider how to install the system itself using the example of an IP55 junction box for outdoor installation of 100x100x50 mm.
Most often, the installation is made in a blank wall of brick or concrete. This may cause some difficulties in the process of how you will drill a niche for it, but the system will be securely fixed. If the box has round holes, then you can use special crowns for the punch. For rectangular or square use grinder with a special diamond disc, designed to work with concrete.
After the niche is ready, be sure to try a junction box on it to make sure everything is prepared correctly. The junction box must be completely placed in the wall so that after installation its front surface is at the same level as the wall.
In some junction boxes there are special plugs that are specifically designed to get a cable in these places. They must be carefully broken or cut, while maintaining the integrity of the overall structure. They start the ends of the wiring according to the scheme.
When you make sure that all the wires have been inserted into the junction box, you can start preparing the mortar to fix it. The principle of fixation is very simple:
- in the niche prepared for the junction box, with a spatula some amount of mortar is put;
- the box with the cables already inserted is pressed in as deeply as possible;
- excess solution, speaking on the sides, are removed;
- if necessary, the box can be held in the first few minutes by hand to give the solution a little grasp.
Helpful advice! Instead of mortar, you can use alabaster. It dries much faster and at the same time it can also withstand the weight of the box.
As with the installation of a junction box for open wiring, and in the case when it comes to a closed system, high-quality installation largely determines the service life and quality of wiring. The main thing in working with electricity is to correctly assess their capabilities and, if necessary, seek help from professional electricians.
