How to disconnect wires in a box

How to connect wires in a junction box

No electrical wiring diagram can do without some kind of connections, branching wires or cables. There is a special box for this purpose. It is located under the ceiling and is a round or square box made of polymer material.

In this material we will tell you how to make connections correctly, demonstrate diagrams, photos and video instructions.

Why use a junction box

Wiring connection in the junction box

There are cases when, when installing electrical wiring, they neglect the installation of such distributors, considering that this is just a waste of time, since the box must first be installed, then the connections to it must be made, which will lead to additional difficulties. It’s easier to simply twist, insulate and simply plaster the wall. But here you need to think a little ahead, since in this case important points are missed:

• No free access to wires. For example, if the socket in your room does not work or the light has gone out, and after checking it turns out that the problem is a lack of voltage. How to check? Completely remove the trim? Tearing off wallpaper and plaster to get to the twist? This will ruin your renovation.
• If you want to install an additional outlet. It is not always convenient to connect it by laying wires from a previously installed outlet. Thanks to the distribution box, you can easily make new connections.
• The regulatory document PUE states that “places of connections and branches must be accessible for inspection and repair,” therefore the installation of such a distributor cannot be neglected.
• The absence of such distributors is contrary to fire safety standards.

As you can see, the distribution box plays an important role. But installing it is just the beginning. All that remains is to connect all the wires in it. What's the best way to do this? Let's look at some ways.

Types of connections

Types of wire connections

What is the task when connecting wires? Ensure good contact between the cores so that the chain does not break and there is no risk of a short circuit. In order to ensure this, you can act in several ways:

1. Twisting.
2. Crimping.
3. Welding.
4. Soldering with a soldering iron.
5. Use of screw terminals.
6. Bolted connections.
7. Self-clamping terminals.

These are time-tested methods that you can use to ensure reliable contact. Let's take a closer look at each of them. You will learn how to properly connect wires using any of these options.

Twist

Twisting wires

Such twists in the distribution box are officially prohibited. The seventh edition of the regulatory document PUE, chapter 2, paragraph 2.1/21 lists all types of permissible connections, but there is no twisting in them.

And this is not surprising, since such a contact is sensitive to pulse current and has a high transition resistance. Over time, the contact will deteriorate and simply burn out.

Due to the fact that the contact area is small, heating occurs under heavy loads and the contact is weakened even more.

It is not recommended to use this type of connection, although some craftsmen still use it. If you choose twisting, all responsibility falls on you.

This option is chosen because of its simplicity. It is enough just to strip 10–20 mm of insulation and twist the wires together using pliers. This is what our fathers and great-grandfathers did. But such a connection is often unreliable, especially if an aluminum core is used.

Crimping with a connecting sleeve

Cross-sectional crimping of copper wires

A fairly reliable method that will require the purchase of a connecting sleeve. You need to select it based on the diameter of the bundle being connected. Depending on the wires you connect, the material of the sleeve itself is selected.

For copper wires the sleeve must be copper, for aluminum wires - aluminum. To ensure a reliable connection, the sleeve is crimped with a special tool called press pliers.

This technology is quite effective and is included, along with other methods, in regulatory documents.

Crimping connection of aluminum wires

To connect this way you need:

1. Remove the insulation, taking into account the length of your sleeve.
2. Twist the wires into a bundle and insert them into the sleeve.
3. Compress the sleeve using press pliers.
4. Insulate the twisting area with heat shrink or insulating tape.

It is not recommended to use pliers in such work, since the connection will not be reliable enough. It is much better to buy press pliers or borrow them from good neighbors.

Welding

Welding wires

This method can be called the most reliable and safe, because the wires are connected using fusion and become one. Due to the fact that the welding will not oxidize, such contact will not weaken over time. But to carry out such work you will need skills in working with welding equipment.

In addition to skills, you must prepare:

• 24 volt welding machine with a power of more than 1 kW;
• welding gloves for skin protection;
• welding glasses or mask;
• sandpaper for stripping wires;
• stationery knife for removing insulation;
• carbon electrode;
• flux, thanks to which the melt will be protected from exposure to air.

Welding copper to aluminum

After all the tools and materials are ready, all that remains is to do the welding, which will not be difficult. The work can be divided into several steps:

1. Remove 60–80 mm of insulation and clean them using sandpaper. The veins should shine.
2. Connect the wires using the twisting method, twisting one onto the other so that the ends are level with each other. It is recommended to make the length at least 50 mm.
3. Pour flux into the recess of your electrode.
4. Place the ground of the device on the bare wire, turn on the welding machine and press the electrode to the top of the twist.
5. Hold the electrode until a ball called a contact point forms. This usually takes 1–3 seconds.
6. All that remains is to clear the point of flux and insulate the welding site with heat-shrinkable tubing or electrical tape.

This type of connection will last a long time. In some old Khrushchev buildings, such welding lasted 50 years and consistently performed its function.

Soldering with a soldering iron

Soldering twists with a soldering iron

The method is very similar to welding, only in this case the wires are connected using solder. For these works you will need a soldering iron. To work you will need:

• soldering iron;
• fine sandpaper;
• rosin (flux);
• brush for applying rosin;
• tin-lead solder.

The operating procedure is the same as for welding:

1. Removing insulation and cleaning with sandpaper.
2. Twisting.
3. Application of flux.
4. Direct soldering. The soldering iron melts the solder, which should flow into the twist itself, reliably connecting the wires to each other.

Soldered wiring in the junction box with a soldering iron

Often copper wires are soldered using this method, but if you purchase special solder for soldering aluminum, you can also solder copper from aluminum.

Soldering is quite reliable, but is not recommended in areas where there may be strong heat. Moreover, under mechanical stress, the connection may weaken.

Using screw terminals

Connection of copper and aluminum wires

This method is fast, simple and effective. And most importantly, such clamps can combine dissimilar metals. For example, if you need to connect aluminum and copper conductors, which in itself, as you know, is contraindicated. These clamps are very simple and compact, and their cost may pleasantly surprise you.

Terminal blocks

To connect wires with clamps you only need to complete 2 steps:

1. Remove 5 mm of insulation.
2. Insert into the clamps and tighten the screw.

Melted terminal block contacts

That's all, as you can see, everything is very simple and fast. It is only important to control the force with which you clamp. If you tighten the screw too tightly, you may damage the wires. You need to be especially careful when working with aluminum wires.

Crimp lugs

The only disadvantage of a screw connection is that when working with a multi-core cable, it must be crimped with a special nozzle to ensure normal contact and integrity of the wire.

Bolted connections

Bolted connection

This connection is quite reliable, but cumbersome. It is not suitable for modern distribution boxes due to its dimensions, but for large old-style boxes it is just right. This method can be used to connect both homogeneous and dissimilar metals. The work is carried out as follows:

1. A steel washer is placed on the bolt.
2. The insulation is removed from the conductors and they are formed into a ring.
3. The first ring is put on the bolt.
4. Then comes another steel washer, which is placed on the bolt after the first.
5. The second connecting wire is put on top.
6. This entire “sandwich” is clamped with a nut.
7. In the end, everything needs to be insulated.

It is this design that makes the contact bulky. If you need to connect several pairs of wires, then this option will not be the best.

Self-clamping terminals

This method can be called the most modern, popular and easy to use. All you need is to buy special terminals at the store. Inside these terminals there is a special paste that prevents metals from oxidizing. Thanks to this, various metals can be inserted into such joints.

The work is as follows:

1. 10 mm of insulation is removed from each wire.
2. The lever, which is located on the clip, rises up.
3. The conductors are inserted into the connector.
4. The lever lowers to its original position.

If your clamps do not have levers, they must be inserted until the terminal snaps into place.

Connecting wires with a terminal block without levers

We have looked at the most reliable methods by which you can combine wires in a junction box. This is a very important stage of electrical installation work, since 70% of errors during the work consist precisely in incorrect connection of conductors.

But if you, even without experience in such work, use the methods given in this article, you can easily do everything in accordance with the requirements of the regulations. But which of these methods to choose depends on your capabilities and desires.

This video shows how to connect wires in a junction box:

You will learn everything about sleeving wires or crimping lugs from the material provided in this video:

Scheme

Box diagram

Switch and socket block diagram

Connection

Junction box connection diagram

Connecting sockets

Switch connection diagram

Junction box

Connecting wires

Wire connection diagram in the box

Source: https://kakpravilnosdelat.ru/kak-soedinit-provoda-v-raspredelitelnoy-korobke/

Methods for connecting wires in junction boxes

The junction box is of great importance in the electrical circuit.

It distributes wires for further electricity consumption.

If you decide to do your own wiring, then first understand all the intricacies.

To understand this process well, let's look at it step by step. We’ll also talk about the types of wire connections and the features of connecting the box.

Types of wire connections

Several types of wire connections are used. Choose the option that is more suitable for your case.

Crimping

This method is used very often. It is produced using a special sleeve that matches the diameter of the bundle of wires.

The sleeve material must match the cable material.

The process is carried out using press jaws in the following sequence:

1. Remove the insulating layer from the wires along a length equal to the sleeve.
2. Twist them into a bunch and insert them into the sleeve
3. Press the sleeve with the wires using press pliers.
4. Insulate the connection with available insulating material.

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Welding

After welding, you get a whole wire that will not oxidize, unlike other connection methods.

The following equipment is required for welding:

• 24 V welding machine with a power of 1 kW,
• flux,
• electrodes,
• protective equipment (mask, gloves).

This is done as follows:

1. Remove the insulation and sand them until shiny with sandpaper.
2. Connect the wires using a twist.
3. Pour flux into the recess of the electrode.
4. Turn on the welding machine, press the electrode against them and hold until a lump forms - a “contact point”.
5. Clean the contact point from flux and coat it with varnish, and then insulate it.

Spike

It is performed in the same way as welding. Only the connection is made using solder heated by a soldering iron.

It is important that the solder penetrates inside the twist. This method should not be used in places where the cable is very hot and in places where there are mechanical loads.

Terminal blocks

This method is simple, fast and inexpensive. In this way, you can connect both identical wires and those of different composition.

The connection is simple: first, about 0.5 cm of insulation is removed, and then they are inserted into the clamp and tightened with a screw.

Bolted connection

This connection is quite reliable, but very bulky.

Therefore, it is used mainly in old-style boxes, since it simply does not fit in modern compact boxes.

The operating procedure is as follows:

1) Place a steel washer on the bolt.

2) Place one of the wires, stripped of insulation and twisted into a ring, onto the bolt. Do the same with the second one.

3) Put on the next washer.

4) Place the ring on the second wire.

5) Put on the last washer and tighten everything with a nut. Insulate the entire connection (although insulation will only add bulk to it).

Connection with self-clamps

The most modern type of connections, easy to use.

Among other things, inside the clamps there is a paste that prevents metal oxidation, which means that different conductors can be connected without problems.

The connection is made in the following sequence:

1. Remove about 1 cm of insulation from the wires.
2. Lift up the clamp lever.
3. Insert the wires into the connector.
4. Pull the lever down (if there are no levers, just snap the clamp)

Box wiring diagram

For safety, reliability and correct connections, it is necessary to know the specific designations of wires.

Wires marked “zero” (blue) and ground (yellow) are connected according to color (see diagram). If you are installing a two-wire system, the circuit is the same except for the ground wires.

The process of phase desoldering (black or red) is much more complicated. If you plan to run only the wire through the box to connect the outlet, then connect their phases together.

If material is used from the box for single-button switches, then it must be twisted together with all the phase wires for the switch. Connect the same one coming from the switch with the phase wire going to the lighting fixture.

The result should be four connections.

When using two-key switches in a three-wire system, a four-wire wire must be used for the chandelier.

In the case of two-wire wiring, a three-core cable is used, since grounding is excluded from the circuit.

Not counting the separate grounding twist, there should be four connections in the box. The wires marked “zero” (blue) are connected to each other. The phases of the sockets are connected to the power cable and connected to the common terminal of the switch with two keys.

Two wires should go from the switch to the lighting fixture.

From all of the above it follows that desoldering the box is a very simple process. It is enough to understand the designation and order of their connection.

Sequence of actions when installing and connecting the junction box

1) Preparation for work. First, prepare everything you need for electrical installation work:

• cables 3*2.5, VVG,
• cables 2*2.5, AVVG,
• two-gang switch,
• fastenings,
• lighting fixture,
• socket,
• round pliers,
• roulette,
• wire cutters,
• pliers,
• flat screwdriver,
• hammer.

2) Applying markings. Mark the installation locations of electrical appliances and where the wires will pass.

This will help calculate the required amount of materials.

3) Installation. First, turn off the power supply.

Route the wires to the junction box (it is better to lay the cable in pre-prepared grooves). Secure the wires using small nails or plastic staples.

In wooden houses, special mounting boxes are usually used.

4) Connecting electrical appliances and connecting wires.

Run about 10 cm of cable into the pre-installed junction box. Remove the overall sheath from the wires and about half a centimeter of insulation from each core.

Connect them using terminal blocks. In this case, a two-wire wire is used (one wire is neutral, the second is phase).

Connect the socket and lighting fixture to the neutral cable. Connect the wire with the phase to the socket and one core of the switch cable. Take the second wire of the switch cable and connect it to the first button, and the third to the second.

5) Check the system operation. Turn on the power and check the operation of the outlet and switch.

Everything should work properly. The process is complete.

Now you know how to connect the wires in a junction box and how to connect electrical appliances. Using this knowledge, you can easily cope with the installation of electrical appliances.

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Read also:

Installing an electric stove yourself

Connecting the electric meter

3 best connection methods

Source: https://nesmetnoe.ru/stroitelstvo/elektrika/139-soedinenie-provodov-v-raspred-korobkakh.html

Connecting wires in a junction box: soldering, twisting, welding, etc.

Electrical wiring in the room must be safe and convenient to use. If you strictly follow this rule, then each energy consumer (chandelier, TV, computer, refrigerator) must have its own protection device against short circuits or overheating of the wiring. You can run a separate cable from the personal circuit breaker for each outlet and switch. Two more criteria oppose this: rationality and economy.

What are distribution boxes for?

Rational wiring looks like this:

That is, the total energy consumption of the facility is evenly distributed among the circuit breakers. In addition, consumers should be divided into groups, for example:

1. Living room and bedroom lighting
2. Kitchen lighting
3. Lighting for bathroom and hallway
4. Socket group (in each room)
5. Power socket group (for powerful consumers, such as an air conditioner or an electric oven)

But with such a scheme, there may be many connections on one wiring line. It is not safe to make overhead connections and hide them in the wall. At a minimum, this does not make it possible to disable a faulty branch while leaving the rest of the circuit operational.

For normal distribution of lines, there are distribution boxes.

They are an insulated container, inside which switching (permanent) of electrical wiring lines occurs. The connection of wires in a junction box can be done in various ways, the main thing is to ensure reliable insulation between phases and a contact that can withstand the load.

The wiring diagram in the junction box allows you to save money when purchasing electrical cables, as well as avoid uncontrolled interweaving of wires in the walls. The so-called radial wires diverge from the shield with protective circuit breakers. On each of them there are connecting nodes: those same distribution boxes.

Important: The wire cross-section may be the same or different. The main condition: the power of the main cable cannot be lower than the power of the final wiring to the consumer (socket, light fixture).

In addition, there are certain methods and rules for connecting wires in a junction box. Let's talk about this in more detail.

General rules for switching electrical cables in distribution boxes

Of course, all requirements for energy supply are set out in the PUE.

This is an electrician's reference book. Moreover, there are fines for violating the Electrical Installation Rules. However, in practice, all these strictures apply only to institutions and organizations. In private households, responsibility ends with the wire coming out of the meter (electricity meter). The rest is up to the homeowner. To prevent an incorrect connection from leading to a fire or electric shock, you must follow simple rules:

• The connection of wires in the junction box is made during a complete power outage. Even if the electrician is wearing dielectric gloves and is familiar with safety rules, accidental contact of the phase wire with structural elements of the building or grounding is possible.
• The type of connection must be the same for each line within the same box. This will protect your line from loosening under load.
• Physical contact of conductors made of different materials (copper with aluminum) is not allowed. When electric current flows, active electrocorrosion occurs. Metals are coated with an oxide film, which impairs contact. The result is sparking, overheating, and complete burnout of the contact connection. If such a need arises, it is necessary to tin the wires using solder. After twisting, the connection must be soldered for at least 50% of the length. The rest of the strand will not corrode because no current flows through it under load.
• It is necessary to exclude the possibility of exposed conductors leaving the box. Even if the cable is completely laid in the wall.
• When connecting without contact devices, that is, using soldering, twisting or welding, an insulating cap must be placed on the exposed conductor. The insulator must be firmly fixed; non-combustible materials are used in its manufacture.
• The ends of the wires inside the box must have at least a 200% margin along the length of the connecting ends. In the event of a break or burnout, it will be possible to re-install without laying a new wire.

In addition, inexperienced electricians often make mistakes and break off wires when stripping the insulation. If the wire is inserted into the box under tension, reconnection will be impossible.

Methods for connecting conductors in a box

There is no single possible method. When choosing a way to connect wires in a junction box, an electrician weighs all factors: from the cost of materials to the expected load.

• Terminals. There is an opinion that this method is the most reliable, but this is a false statement. Most often, terminals are used on boxes with ready-made contact pads.

This connection of wires in the box allows you to disconnect one of the lines at any time (for example, for repairs) without causing damage to the entire power system. There are two ways to connect, directly to the block (by making a ring from a wire core), or using a terminal. With the ring everything is simple, you just need to ensure that the wire is laid in such a way that when tightening the threaded connection, the contact does not loosen.

But with terminals everything is more complicated. It is irrational to crimp a single-core wire: you can mechanically damage the conductor, and the core will break off at any moment. And when laid in a box, a single-core cable with terminals takes up a lot of space, and it is difficult to separate different phases at a sufficient distance.

An excellent result is obtained when crimping a multi-core soft cable; the contact terminal fits comfortably. But stationary installation of multi-core cable is nonsense.

Bottom line: Terminal blocks in the distribution box are convenient, but it is better to make the connection directly to the conductor under the screw, without using crimp terminals.

There are modern boxes with quick-installation contact blocks. This solution is really convenient, but is designed for light load.

Thus, the use of contact blocks is justified only if it is necessary to periodically disconnect one of the lines. And even then, sooner or later the conductor will break off.

• For standard wiring in an apartment (or household), the classics are still more suitable:

Welding wires in a junction box has been used since time immemorial. Anyone who repaired their Khrushchev or Brezhnev cars probably noticed a drop of solidified melt at the end of the aluminum strands in the boxes.

Today, the use of aluminum wiring is prohibited by the PUE, and the welding connection method is still popular. The point is this: after carefully twisting the stripped wires, the contact of the welding machine is briefly applied to the end point.

Usually this is a compact device of low power. It is used by almost all professional electricians. Works on the principle of a spot welding spotter. It will not be possible to light an arc, but the metal at the point of application melts properly. The figure shows the simplest circuit that can be assembled at home.

The connection quality is more than sufficient. In addition to the total twist length (40–50 mm), the ball at the end forms a point with minimal resistance. An additional plus is that this twist will not unwind even when moving the wires inside the box.

If a welding machine is not available, we limit ourselves to ordinary twisting. Of course, we make the connection not with our fingers, but with the help of pliers. All ends of the conductor must be stripped (but not reduced in cross-section), the length of the bare part before twisting begins is at least 70 mm.

Twisting is done after the wires are finally secured in the box. If the cable moves, the connection may become weak. The result is sparking, overheating, and contact breakage. It will be good if there is no fire.

• As an option, after twisting, the wires are soldered in the junction box.

Important! There is a widespread opinion among amateurs: under load, the twist will heat up and the solder will melt. Firstly: a load capable of heating a conductor to the melting temperature of solder is unrealistic at home. Of course, provided that the circuit breakers are in working order. Secondly: heating during twisting occurs due to loose contact, and this can be solved by soldering.

The reliability is not much worse than with welding. In this case, there is no need to purchase (do it yourself) a welding machine, a fairly powerful soldering iron, or even a hair dryer.

Tip: Use the most powerful soldering tool possible. It is better to expose the contacts to high temperatures for a short time than to heat the contacts slowly and for a long time with a weak heater.

During heating, monitor the condition of the insulation. If it starts to melt, take a break until it cools completely. Immediately after soldering, do not move the wire; allow both the solder and the insulation to cool.

Use refractory solders; these alloys have higher strength characteristics.

• Crimping. From the point of view of electrical conductivity, the quality of contact is no better than that of conventional twisting. But the strength of the connection increases significantly. If it is not possible to weld or solder the twist, crimp it using a special sleeve.

You can get by with pliers, but a special tool is still more reliable. There are bushings for parallel splicing of wires, and there are for fixing twists. There is no fundamental difference. If there are two or three conductors, parallel crimping is suitable. For larger quantities - crimping after twisting.

In fact, the methods discussed above are a modernization of the good old twisting. You should not be skeptical about the issue. Due to poor contact in the junction box, many fires occurred and damage to household appliances was caused. Therefore, when repairing electrical wiring in your home, use technical means to improve contact in the twist to the maximum.

Modern methods of connecting wiring in a box

The so-called quick fix pads. These products are widely offered in online stores and building materials markets.

Indeed, such devices make installation quick and convenient. The appearance of the connection is also pleasant. Therefore, such “electric clips” are loved by electricians who perform custom work.

However, this method has serious drawbacks. Let's make a reservation right away: the manufacturer does not promise high connection power: the characteristics are on the case. For an LED lamp, connecting a computer or TV - just right. But a refrigerator, electric stove, boiler cannot be connected through such a distribution box.

The contact area in such “quick releases” is small; the pad is connected to the conductor tangentially. With a light load, the current does not heat the surface too much. And when a serious consumer is connected, sparking, heating, and burning out of the connection will begin.

Conclusion

With all the variety of ways to connect wires in a box, traditional twisting remains the most reliable. Welding or soldering significantly improves contact.

No serious equipment is required; all work can be completed with basic electrical engineering skills.

Source: https://ProFazu.ru/provodka/montazh/soedinenie-provodov-v-raspredelitelnoj-korobke.html

Wire connection diagram in the junction box

We carry out installation in a junction box

Correctly connecting the wires in the junction box is a significant factor in the reliability of your electrical network.

And if you consider that more than 50% of all connections are concentrated in distribution boxes, then this element of your electrical network of a house or apartment becomes especially important. At the same time, we must not forget about the clarity of the connection, as well as its maintainability.

Based on all this, let's look at distribution boxes in more detail.

Rules for installing distribution boxes

First of all, let's look at the rules for installing junction boxes. After all, the reliability of your electrical network depends on this. Moreover, these rules are quite logical and do not require major investments.

Location of distribution boxes in the apartment

 So:

• First of all, remember that the junction box must be made of a material that matches the installation surface. So, on combustible surfaces, for example, wood, distribution boxes made of non-combustible materials should be installed. Usually it is metal.
• If the distribution box is mounted on a fireproof surface, for example, concrete, then boxes made of fire-resistant materials can be used. Usually, for these purposes, standard boxes made of special plastic are used, which are widely available in hardware stores.
• It is also worth remembering that, according to clause 2.1.22 of the Electrical Installation Code, a supply of wire must be provided at all branches and connections of conductors to ensure re-connection. The cost of following this rule will be mere pennies, but if it is necessary to reconnect, this reserve will become “golden”.
• It is also worth specifying the location of the distribution boxes. In general, it is not standardized, but they are usually located at the entrance to the room from the side of the door handle. The height of the distribution box is usually 10-20 cm from the ceiling. This allows you to protect it as much as possible from accidental touch and visually hide it.

Connecting various electrical receivers in the junction box

Now you can directly examine the connection of the wires in the distribution box. After all, it largely depends on the type of device being connected, as well as on the number of these devices. Sometimes it is advisable to create two or even three distribution boxes for one room rather than trying to fit all the connections into one.

Connecting group wires

First of all, we need to determine whether we have an end or pass-through junction box. Ideally, each junction box should be an end box.

A terminal box is a junction box that does not have wires connecting it to other junction boxes. A pass-through is a box that has such a connection.

The photo shows a walk-through junction box with an outlet connection

So:

• The end distribution box contains three cores of the power cable or wire from which the end consumers are powered.

Note! There should be exactly three of these wires for a single-phase network. Of which, one neutral wire, according to clause 1.1.30 of the PUE, must have a blue color, one protective grounding wire, which is designated in yellow-green color, and a phase wire, which can have any other color designation.

• The feed-through junction box has three supply wires, which are usually connected to the terminal block. The next distribution box is powered from the same terminal block. As a result, we get two wires connected to each other.
• Another possible option is if for one group the box is an end box, and for another group it is a pass-through box. Moreover, usually the wire for which the box is a feedthrough does not have any connections in it. It just runs along the box.

 Connecting sockets

First of all, let's look at the connection of wires in the junction box at home when connecting an outlet. After all, this is one of the simplest connections.

Connecting a socket in a distribution box

• So, in the junction box we have three strands of the supply wire. As we have already said, this is phase, zero and ground, indicated by the corresponding colors.
• To connect the socket, we need to connect the wire going directly to the socket to the corresponding cores of the power cable. In this case, color coding should be observed.

Note! All connections in the junction box should be made using terminal blocks, soldering, crimping or welding. This is required by clause 2.1.21 of the PUE, which prohibits the use of twisting.

• If the connection is made in a pass-through junction box as in the video, then the connection can be made both with the supply cable and with a cable feeding another junction box. After all, thanks to the connection between themselves, they are one whole.

Switch connection

The wiring diagram in the junction box for connecting the switch is somewhat more complicated, but also quite simple and understandable. And even a two or three-key switch should not cause you problems.

Connecting a two-gang switch

 So:

• First of all, we connect the switch. To do this, it is necessary to connect the wire leading to the switch input to the phase of the supply cable. We lead the wire from the switch output into the distribution box.
• Now we connect the lamp. First of all, we connect it to the neutral and protective power cable, the wires going to the lamp. After this, we connect the phase wire of the lamp to the wire coming from the switch terminal.
• As for two-, three- or even four-key switches , the same principle is followed here. The only difference is the connection of the phase wire from the switch terminal.
• If this is a chandelier with two operating modes , then it has two phase wires. We connect our outputs from the switch to them.
• If different lamps will be connected from the switch , then our instructions advise first of all to connect their neutral and phase wires. Then one phase wire from the switch terminals to each lamp.

Connecting the lamp and socket

But to connect an outlet with a switch there will be a more complex circuit. The connection of the wires in the junction box is a little more confusing in this case. But if you analyze the diagram completely, then there is nothing complicated in it.

Connection diagram for switch from socket

• First of all, using the method described above, we connect the outlet.
• Now we connect the neutral and protective wires of the lamp. This is done in the same way as with a normal connection.
• As for the phase wire for the switch, there can be two options. You can purchase a single product, a switch with a socket in which the connection has already been made. Or you can purchase a separate switch and a separate socket. In this case, you will make the connection between them yourself.
• To avoid wastage of wires, in this case it is advisable to connect the switch directly from the phase contact of the socket. We connect this wire to the switch input.
• The wire from the switch output, as with a normal connection, is brought out into the junction box. Here we connect it to the phase wire of the lamp.

Types of connection of electrical wires in a junction box

In a field such as electricity, all work must be carried out strictly, accurately and without a single mistake. Some people want to figure out such work on their own, not trusting third parties to carry out a responsible mission. Today we will talk about how to properly connect wires in a junction box. The work must be done efficiently, because not only the performance of electrical appliances in the house, but also the fire safety of the premises depends on it.

About the distribution box

In an apartment or house, wires from the electrical panel are routed to different rooms. There are usually several connection points: switch, sockets, and so on. In order for all the wires to be collected in one place, distribution boxes were created. They carry wiring from sockets, switches and are connected in a hollow housing.

So that during repairs you do not have to look for where the wires are hidden in the walls, electrical wiring is laid on the basis of special rules prescribed in the PUE (Electrical Installation Rules).

The main recommendation is that all connections are made in the junction box.

Distribution boxes are classified according to the type of fastening. So, there are boxes for external installation and internal installation. For the second option, you need to prepare a hole in the wall into which the box will be inserted. As a result, the box lid is located flush with the wall. Often the cover is hidden with wallpaper or plastic during repairs. As a last resort, an outer box is used, which is attached directly to the wall.

There are round or rectangular junction boxes. In any case, there will be at least 4 exits. Each outlet has a fitting or thread to which a corrugated tube is attached. This is done to quickly replace the wire. The old wire is pulled out and new wiring is laid. It is not recommended to lay the cable in a groove on the wall. If the electrical wiring burns out, you will have to dig into the wall and disturb the finish in order to carry out repair work.

Connecting the wires in the box

There are several ways in which conductor connections can be made in junction boxes. Note that there are simple and complex methods, however, if executed correctly, all options will ensure the reliability of the electrical wiring.

Method number 1. Twisting method

It is believed that the twisting method is used by amateurs. At the same time, this is one of the most reliable and proven options. PUE do not recommend using twisting, since the contact between the wires is unreliable. As a result, the conductors may overheat, putting the room at risk of fire. However, twisting can be used as a temporary measure, for example, when testing an assembled circuit.

Source: https://www.bazaznaniyst.ru/sem-sposobov-soedineniya-provodov/

Rules for connecting wires in a junction box: an overview of all methods and expert advice

An extremely important stage in installing home electrical wiring is connecting the wires in the junction box.

If the electrical contact between them turns out to be poor, the resistance in this area will increase significantly and it will heat up, which can lead to a fire.

It is not always possible to identify a defect by measuring the resistance of the phase-zero loop, since often the contact in a poorly made connection is good at first and weakens only over time. Therefore, it is important to study the technique of performing electrical circuits and strictly adhere to time-tested rules.

How to connect correctly?

Junction boxes with built-in terminal blocks are available. Connecting conductors to them is not difficult: the stripped conductors are inserted into the terminals and secured with a screw or spring.

But more often the box is just a body with a lid and performs only two functions:

1. insulation of electrical contacts (potentially dangerous places) from building structures and finishes, usually consisting of flammable materials;
2. providing quick access to conductor connections.

In such boxes, the installer connects the wires in any way at his discretion. There are a lot of connection options. Some use special devices, others do without them. For a complete understanding, it is worth considering this issue in detail.

In electrical circuits, direct contact between aluminum and copper is not allowed: both materials are quickly destroyed due to electrochemical corrosion.

Connection methods

In the process of ensuring contact of conductors, they strive to achieve two tasks:

1. provide a large contact area;
2. prevent oxidation of the surface of the cores (the oxide film has a high resistance).

Several connection methods are used.

Connecting insulating clamp (PPE)

PPE is a plastic cap with a conical spring inside, made of square wire, installed as follows:

• the ends of the cores are freed from insulation to a length slightly less than the depth of the cap and stripped;
• twist, but only slightly;
• Screw on the cap: the spring will press the wires tightly against each other.

PPE is available in an assortment - for wires of any cross-section and different quantities. But the possibilities are limited: they connect either two wires with a cross-section of up to 4 mm2, or 4 wires with a cross-section of 1.5 mm2.

For aluminum wires, caps are produced with a special paste inside that protects the metal from oxidation. PPE makes twisting more reliable, but its spring also weakens over time, causing contact to deteriorate.

Soldering

Solder the wires in the classic way:

• strip the veins to a copper shine and, if necessary, tin;
• twisted into a twist, as described above, but less tightly (so that the solder penetrates inside);
• cover the twist with flux;
• soldered;
• isolate.

Using special solder and flux, solder copper wires to aluminum wires. Due to its increased activity, acid flux cannot be used: it destroys the connection.

Soldering provides contact of high quality and reliability, but over time the resistance at the connection area increases.

Sleeves for crimping

The sleeve is a thin-walled tube. The diameter is selected according to the cross-section of the wires being connected. The compliance of these parameters is very important, since it directly affects the quality of contact.

Installation procedure:

• the stripped ends of the veins are coated with quartz-vaseline paste;
• inserted into the sleeve from opposite sides;
• crimp the connection with a special tool - a crimping press or pressing pliers;
• isolate.

Crimping tools can be manual or mechanized.

Using simple pliers, the sleeve is crimped in several places; more advanced crimpers perform crimping in one go. If convenient, the wires to be connected can be placed in the sleeve on one side. Then choose a product with a cross-section larger than the total cross-section of all cores.

Bolted connection

A very simple method and at the same time much more reliable than twisting:

• a washer is placed on a screw or bolt of small diameter;
• then the first core is put on, the end of which is twisted into a ring;
• a similarly twisted second core is put on;
• the washer is put on;
• the nut is screwed on and tightened;
• the connection is wrapped with electrical tape.

When connecting an aluminum conductor to a copper conductor, another washer is placed between them, which must be galvanized.

Terminals

The connector is a terminal block - a small product with two inputs for wires, a brass sleeve connecting them and a mechanism for securing the wires. The most popular terminals are Wago, but many other brands are also widely available. Installation is extremely simple: the stripped conductors are inserted into the contact connectors and fixed.

According to the method of fixation, the terminals are divided into:

1. self-clamping . The contact connector has a spring that automatically blocks the inserted wire. This is a one-time option: you cannot pull out the wire without damaging the connector;
2. clamping The connector is clamped by turning the lever. Such a terminal can be disconnected by returning the lever to its previous position;
3. screw . The wire is clamped with a screw, but not directly, but through a brass tab. It is not recommended to use cheap terminals without such a tab: the connection will burn out. Screw terminals are superior to the previous two in that the user can control the clamping force.

Terminals are selected not only by wire cross-section, but also by rated current. Before installation into the terminal connector, a multi-core cable is soldered or a tip is pressed onto it.

Connection diagram

The connection diagram in the junction box is extremely simple:

• the corresponding cores of wires laid to the sockets are connected to the phase, neutral and grounding conductors of the supply cable;
• for lamps, single-core wires leading to switches are connected to the supply cable phase;
• “zeros” laid to the lamps are connected to the neutral core of the power cable;
• if necessary, for a more rational connection, a wire leading to the next junction box located in another part of the room is also connected to the power cable.

The phase to the lamps is started from the output contact of the switch.

Which connection is better?

The choice of connection depends on a number of criteria:

1. wire material (same or different);
2. number of wires in the connection;
3. wire diameters (same or different);
4. experience and skills of the master, availability of additional tools;
5. Is a detachable connection required?

For the average person, it is easier to connect the wires using terminals or a bolt method.

The first, despite the relatively high cost of the terminals, is more preferable, since the bolted connection is large in size and will not fit in every junction box. The disadvantage of terminals is the danger of running into a fake or choosing the wrong product based on the rated current.

The most reliable, durable and high-quality connection method is welding. But this requires a welding machine - quite specific equipment that not everyone has. That’s why professionals often choose crimping with sleeves.

Soldering is practically not used when organizing connections in a junction box for the following reasons:

• it is extremely difficult to solder wires located under the ceiling, especially if there are several of them in the connection;
• over time, the resistance of the soldered joint increases, which, given the high current intensity inherent in power circuits, produces noticeable heating;
• low-melting solder melts during short circuits (short circuits) and even overload, as a result of which the contact in the connection is broken.

Soldering is usually used in low-current switching lines. Many professional electricians speak highly of PPE. One installation company reports on its website that it has been using such clamps for more than 15 years and they have never failed. Employees of this company use Wago terminals only at the insistence of the customer, since, in their opinion, the plastic parts of these products often melt under prolonged maximum load.

To connect aluminum and copper wires, a special sleeve is required - brand GAM or GMA. As experienced electricians testify, it can be difficult to find it on sale.

Connection according to PUE

When installing electrical networks, specialists are guided by the following documents:

• PUE 7 (Rules for the design and operation of electrical installations);
• SNiP 3.05.06-85 “Electrical devices”;
• GOST R 50571.5.52-2011 “Low-voltage electrical installations”.

Source: https://proprovoda.ru/provodka/provoda-i-kabelya/soedinenie-v-raspredelitelnoj-korobke.html

How can you connect the wires in a junction box?

The connection of wires affects the safety and reliability of electrical wiring. It is performed in different ways, using connecting devices and devices, depending on the characteristics of the wires.

Why use a junction box?

A distribution (otherwise a junction box, a branching box) is a type of installation box in which wire switching and electrical connections are made. It can be round, rectangular, square in shape, plastic, steel, fiberglass, aluminum in material.

The device is a container, the purpose of which, in any method of connecting wires in a distribution box, is to hide the branch of the electrical network. In addition, it allows you to effectively redistribute the load on networks and prevent short circuits in them.

There are many ways to connect wires in a junction box. The simplest one - twisting - was previously a priority. Today it is considered dangerous and unreliable. It was replaced by special connecting devices, devices designed for the various characteristics of the cables being connected.

Methods for connecting conductors

Correctly connecting the wires to each other means ensuring the reliability and safety of the electrical network. There are numerous types of wire connections. You can use long-used ones - twisting, soldering, bolting. It’s easier and faster to get the job done by using a cable connector - a special device that allows you to reliably connect cables of different diameters, single- and multi-core, from various materials,

Using Terminal Blocks

Blocks for connecting wires are a type of electrical installation products. They are called terminal blocks, terminals, terminal blocks, terminal blocks, KB, terminal clamps, terminal connectors. Contains 2 metal contacts or more. The latter have nodes in which cables are secured and are placed inside a dielectric housing, often sealed (filled with gel).

There are many types of terminal connectors. They are distinguished:

• by installation method: screw, detachable, push, barrier, pass-through;
• single-, double- and multi-row;
• for one-, two-, three-row and multi-tier cables;
• angular and straight;
• for single- and multi-core, flexible conductors;
• according to the method of wire clamping: screw, spring, knife, end.

The cable connector is inexpensive. Contains a clamping cage enclosed in a plastic housing. Phosphor bronze and stainless steel are used to make the clamp; housings - polyamide; screws - brass, nickel-plated or galvanized steel.

Connect the electrical wires to the device in the following order:

• the insulation is removed from the ends of the cables;
• 1 conductor is inserted into the clamping cage, fixed, depending on the type of terminal block, with a screw, spring, or knife;
• To form a network, 1 or more conductors are installed in it and clamped in the same way.

Spring terminals

These are terminal blocks in which the cables are fixed by a plate (busbar) under the action of a spring force. Types of connecting electrical wires using the following devices:

• fast, allowing you to save up to 80% of the electrician-installer’s time;
• do not require the use of a screwdriver - the conductor is fixed by the terminal mechanism after insertion;
• provide a constant contact force on the conductor and do not deform it;
• allow you to connect cables of different materials and cross-sections.

How to connect two wires:

• remove the insulation from the conductors (1 cm);
• raise the lever on the clip body;
• insert the end of the cable into the connector;
• lower the lever into place.

Terminal blocks without levers are available. In them, the wire is automatically clamped after being inserted into the groove of the connector. Most of them are produced filled with a special gel inside, which makes the devices sealed connectors, providing the highest level of protection.

Installation of PPE caps

This type of cable connector has a conical cap made of non-flammable plastic. Inside it may contain a conical metal spring or a bushing with a large thread. Used for better twisted connections, it protects it by providing reliable insulation.

Caps with a spring are screwed onto a pre-made twist. The spring moves apart due to the pressure of the conductors, providing additional compression at the connection point.

Threaded caps can be screwed onto cable ends without pre-twisting. After making 2-3 turns, a reliable twist connection is obtained inside the PPE cap.

Crimping with special sleeves

The electrical wire connector consists of tubular elements - sleeves. Suitable for networks with medium and high current. Provides good electrical contact, the connection strength is the highest among the methods used. The disadvantages of this method are that the conductor cannot be disconnected in the future.

Source: https://odinelectric.ru/wiring/wires/kak-soedinit-provoda-v-raspredelitelnoj-korobke

Junction box and what it is

All wires that supply electricity to a house or apartment come out of the electrical panel. Each room has several sockets and switches. To collect all the wires in one place and assemble a wiring diagram, junction boxes were invented. This is where they are connected for the further operation of all devices. For laying the wiring, established rules are used, described by the PUE, which stipulate the rules for laying wires and cables.

It also contains recommendations regarding the conduct of connections and branches of wires, specifically in the junction box.
According to these recommendations, the wires are laid along the top of the wall, at a distance of 15 cm from the ceiling surface. As soon as the wire reaches the turning point, it is lowered perpendicularly down, and the specialist installs a box at the branch point. According to this principle, all wiring cores are connected according to a given diagram.

Depending on the type of installation, the boxes are:

• internal, used for hidden wiring;
• external, used for external connection.

When installing an internal box, you need to make a hole in the wall, into which the box is then installed. When the cable is supplied and connected, the box is closed and the lid is flush with the wall surface.

In some cases, such a box is masked with wallpaper or a thin layer of plaster. If the thickness of the walls does not allow installing an internal box, then the only option is to install an external type box.

It is mounted on the wall surface, so complex preparatory work is not required.

Depending on the shape, the box can be:

The number of pins varies, in most cases there are 4, but sometimes there are more. Each terminal is equipped with a thread or fitting to which it will be convenient to attach a corrugated hose. The corrugated hose is designed for convenient location of electrical wires, so replacing a damaged cable will not cause difficulties even for a beginner:

• disconnect the corrugated hose from the junction box;
• disconnect from the socket or switch;
• pull a little;
• pull out;
• put another in its place.

If the cable was laid in a groove, then replacing it will be more difficult.
You will need to dig into the wall and remove the damaged cable, and lay a new one in its place. After such work, the wall will have to be repaired. The task of distribution boxes:

• Increase the maintainability of the power supply system. The accessibility of all connections allows you to identify the damaged section of the circuit. If all the wires were laid in corrugated hoses or pipes, then replacing damaged ones will not cause much difficulty.
• Providing free access to connection points. Since the majority of electrical problems arise from poor-quality or incorrect connections, you can easily check their condition by opening the junction box.
• Ensuring fire safety.
• Financial savings. By using a distribution box, you don't have to run a cable to each outlet.

Terminal blocks

These are plastic parts, inside of which there is a brass bushing with screws on both sides.
To fasten using this method, you need to insert the stripped ends on both sides of the block and tighten the screws with a little force. This method is not complicated, but you need to keep in mind that the pads come with different outlet holes, suitable for a certain wire cross-section size. Advantages:

• low cost;
• reliable connection;
• possibility of connecting aluminum conductors with copper ones.

Flaws:

• Such products are often found with poor quality, so it is difficult to talk about a high-quality connection.
• They allow you to connect only two wires to each other.
• Such blocks are not recommended for connecting aluminum and stranded wires. This is because aluminum is very brittle and the wires are very thin, so if the screws are over-tightened, the contacts may be damaged.
• Soldering can provide a more reliable connection.

connects wires by a clip

PPE caps

Connecting insulating clips, this is how PPE stands for. People call them more simply, caps. Externally, they resemble caps made of plastic. There is a spring inside that holds the cores. Such products are most often used to fasten cores in junction boxes.

Advantages:

• affordable price;
• lack of possibility of fire, which is explained by the material of manufacture;
• quick installation;
• large selection of products in sizes and colors.

Flaws:

• insulation and fixation are not of high quality;
• connecting aluminum to copper is impossible.

Crimping with sleeves

This option is considered the most reliable. Its essence is simple: for joining, insert the stripped ends into a special sleeve and crimp. Finally, the sleeve is insulated. The arrangement of the wires can be any, from two stolons of the sleeve, or from one. In the first case, the junction of the wires should be in the middle of the sleeve; in the second case, the total cross-section of the wires should not be larger than the cross-section of the sleeve.

Advantages:

• high quality connection and insulation;
• low cost.

Flaws:

• Once a cartridge has been used, it cannot be restored; it is disposable.
• Availability of special tools: press jaws and pipe cutter.
• the presence of a special sleeve for fastening aluminum and copper cores.
• Installation work this way will require more time.

Soldering or welding

All experienced electricians recommend using welding or soldering. To connect several cores in a junction box, follow these steps:

• expose the ends of the wires;
• twist the prepared ends;
• solder the wires with a soldering iron or gas torch;
• let the solder cool;
• insulate the ends with electrical tape, heat-shrink tubing or cambric.

Please note that cooling ends with solder in water is strictly prohibited, as this may lead to deterioration in the quality of the bond.
Advantages:

• reliable and strong fastening of wires.

Flaws:

• availability of special tools and skills to work with them;
• complexity of the soldering process;
• permanent connection point;
• restrictions on some conditions of use, stated in the PUE;

Stranding and insulation

An old but effective way of fastening two or more wires.
The principle of work is simple: strip the ends and carefully twist them together using pliers. The twisting area must be insulated. Advantages:

• ease of operation;
• minimal material costs or their complete absence if you already have purchased electrical tape.

Flaws:

• not the best quality bonding;
• Aluminum and copper conductors cannot be connected.
• increase in twist resistance over time.

In most cases, this method is used when carrying out temporary electrical wiring, and cambrics are used for insulation.
At the moment, the PUE prohibits this method of connection because over time the twisting resistance increases and the contacts begin to heat up.

Walnut clamp

Fastening with a “Nut” clamp is used quite often.
This is a clamp with two plates and 4 screws at the corners. To fasten, you need to strip the ends of the wires, insert them into the plate and secure them with bolts. Place a carbolite shell on top. Advantages:

• low cost;
• no difficulties during fastening;
• connection of copper and aluminum conductors;
• high class insulation.

Flaws:

• such fastening requires periodic checking, and if loosened, the screws must be tightened;
• The dimensions of such a clamp will not allow it to fit into the junction box.

Using a bolt

Fastening with bolts is not only the simplest method, but also quite effective. All you need for the job is a bolt, 3 washers and a nut. The essence of the fastening is very simple, you need to put a washer on the bolt thread, screw on the protected core, again a washer on top, again a core, and another washer completes it. At the end of everything, the bolt is firmly tightened with a nut and insulated.

Advantages:

• minimal costs and easy execution of work;
• connection of aluminum and copper conductors.

Flaws:

• poor quality of fastening;
• high consumption of electrical tape;
• the bolt with electrical tape may not fit into the junction box.

What to do if there are several wires?

In a normal situation, you only had to connect two wires.
But what if there are several such wires? There are several solutions for this:

We have already told you how to connect the wires in the junction box, and which one you use is up to you. But experts advise giving preference to the first method, as it is the most effective.

What to do if the wires are of different sections?

For high-quality joining of wires with different cross-sections, experts recommend using spring or regular terminal blocks. Your goal is to firmly fix the wires with a screw. If the wires used are made of different materials, then to prevent oxidation you need to use pads with paste.

An alternative method of fastening would be to solder them.

How to connect stranded and solid wires

There are no special conditions for fastening such wires separately, so you can use any of the above methods. For convenience, we have given the advantages and disadvantages of each of them, so after studying them carefully, you can easily decide on the fastening method.

Source: http://electry.ru/elektromontazhnye-raboty/kak-soedinit-provoda-v-raspredelitelnoj-korobke.html