Wire connection in junction box

There are usually several distribution boxes. There are fewer automata, the builders set a minimum. Devices are not enough. Let's see how to properly manufacture, where to put and how to make the connection of wires in the junction box, and what to do if there are too many wires.

About distribution boxes

According to the rules, the circuit breaker is installed in the phase conductor, and in the zero, any switches and keys are prohibited. Especially said concerns lines of lighting. Let's talk about what the correct junction box looks like. There were two automatic protection machines for an apartment, but now the only one is put( in new buildings).The builders understand that you can’t put a normal junction box for everyone, it is troublesome, it requires accuracy and takes a lot of time. People have to wrestle with how to properly connect the wires in the junction box. And everything is extremely simple.

Distribution box

Zero bus

It must be present! A zero wire is planted on it, but! Grounding is not allowed here. If there is a separate PE( protective zero), an additional tire is put. The nuances are important - the phases will start being torn by automata, but the zeros and grounding go straight to sockets and to other places. It is assumed that the mass of the branches, and separate branches are not allowed to twist, merge couplings, etc. For example, for the hob, the wire is put directly to the distribution panel. Other similar cases are known. Branch required. Tire and provides the owner with a similar opportunity. Tire - a piece of metal with good conductivity, often brass, equipped with numerous means of installation lived. Usually a rail with screw clamps. Connection turns out durable, easily understands for change of switching. Please note that there must be a blue insulated core.

Earthing bus

Conducted with yellow-green insulation. Sometimes PVA3 wires are supplied with two-color, in other cases with one-color cambric. Grounding is yellow, green, or a combination of colors. This bus is separated from the zero, so require the rules( for example, the PUE 7).Not everywhere is grounding, most fixtures do not need the latter( it is permissible to make artificially).In this case, the wiring is conducted with wire PVS2( it can be the same).The colors of the cambric do not always coincide with the pictures in Yandex. Look, for example, in the photo: lilac and pink. The cord from the old carry( extension cord) is shown. The first color is usually taken as the neutral wire, the second will be the phase. About grounding out of the question.

Old cord

Phase wire

Usually brown or white, sometimes black or red. Depends on the number of lived and network destination. Typically, wiring with 4 or more branches is used for three-phase networks. Blue wire is zero, and grounding is right to be absent. Phase sometimes red. It is permissible to use a wire for 4 cores for the common trunk of two branches of kitchen sockets, and it is planned to include a hob in one( or both).In the latter case, branching is not allowed, and the wire is located directly on the switchboard. Plus a single wire in simplicity pulling through the channels passing inside the wall. Similarly, a five-core wire is used for standard four outlets in the kitchen. And under one detach the indivisible pair, and here include the hob. In the described case, one phase wire becomes zero. Usually with a black cambric.


Mounted on DIN rails in rows. The phase wire going from the outside( from the entrance), branches with jumpers on the desired number of channels. Sometimes there are two entrances to the apartment. It is logical to calculate the power in two directions and split approximately equally or proportionally to the power of the input automats at the entrance( rarely the same, see photo).There are many options for performing junction box. A number of tips to help: highlight the branches for lighting, outlets and climate technology( also sockets, but constantly occupied) of any room. Separate automatic get a balcony, hob. A fair question arises: how to cross the wire branch? Usually taken as an analogue, as at the entrance. The reason is simple: it is convenient to close conductors of automatons of equal thickness into the terminals of automata. A separate phase bus to create is not accepted. Apparently, for security reasons. The installation of the conductors is carried out in such a way that bare areas are not observed.

Protection circuit breaker


In private households the network enters from the post, it is logical to install the junction box with OPS.Implied dischargers or limiters( often of the varistor type), which take on sharp peaks and surges, closing them to ground. Now pay attention! If it is impossible to combine a grounding bus and a zero bus in an apartment, this, on the contrary, must be done at the entrance to a household. For example, the pole is equipped with a lightning rod with its own ground loop from the pin, the design is driven inside the switchboard( from the tire in the form of a steel bar going underground).Additionally, under the foundation should create a ground loop home( at least two steel stakes with a diameter of 16 square millimeters, a length of 2.5 meters, a distance of 3 meters), combined with the zero bus is now at the entrance to the house. Note: it is possible to do at the switchboard level. In an apartment, this is considered a mistake, but for a separate household this is done.

Phase contactor

The new difference in the switchboard of an apartment is the absence of a counter and switches for de-energizing the system. Usually located in the entrance. As for home ownership, in parallel with the OPS put the contactor on the desired number of phases. Sometimes the zero wire is also broken. In the described situation, the contactor detects an additional pole under the specified circuit. Then according to the rules should be the counter. It is selected according to the number of phases and the demand of the company of the supplier of electrical energy( a kind of power for payment).The possibility of charging is taken into account: it is permissible to lay the numbers for different times of day, weekend and weekdays, holidays in modern counters. As a result, it is possible to save. The meter is usually programmed separately, by officials or in their presence, then sealed. In some models, additional features are installed, for example, overload protection.

How to make the

wiring cross-section We agreed that the input uses a core made of identical material as the input cable, or of similar thickness for copper( there is no sense in messing with aluminum, which is used primarily to reduce the specific weight of the cables).For owning one needs to assess the consumption and functionality of the switchboard. For example, standing on a pole is not very convenient to use.

For example, winter, you need to cut down the phase. Go through the snow, and there is an obstacle. In addition, it is irrational to make a strong branching at a great distance from the building. We'll have to pull a lot of lived, increasing the amount of work and expenses. Here in the house and there is a cable for three or four cores maximum: one per phase, plus zero.

The ground loop is arranged under the foundation, from which comes the main yellow-green vein, following the path to the internal switchboard of the house. Please note: the above circuit comes in the form of steel reinforcement( or flat steel) the conductor of the lightning rod. From it you can not take the ground copper conductor for the simple reason - the resistance of steel is too high( 7 times more copper).According to the rules, the grounding section is not less:

  • 10 square millimeters in aluminum.
  • 6 square millimeters of copper.

The color of the cambric in the house is yellow-green( one color or both).On the internal switchboard of the house is the only bus, where the zero wire is routed. And on the area of ​​premises it is prohibited to combine protective( yellow-green) and working( blue) cores. Automatic switchboard dials on the branches( see above) the desired bandwidth current. It is customary to take( author of A. Zemskov’s councils):

  1. . For lighting devices, a wire with a cross section of 1.5 square millimeters for copper with a protective machine for 10 A.
  2. For sockets( climatic appliances included) and a balcony - 2.5 square millimeters for copper with protectiveautomatic 16 A.
  3. On the oven( for cooking) - a cross-section of 4 square millimeters of copper and a protective circuit breaker of 20 A.
  4. For the hob - 6 square millimeters of copper and a circuit breaker of 32 A.


Let's try to explain the choice of numbers. Suppose there is a hob in the kitchen. The efficiency depends on the type. Let the "bad" electric burners stand. Their total power usually fluctuates around 5 kW.Corresponds to a current of 22.3 A. Permissible for a core with a cross section of 6 square millimeters in the worst case is 34 A. The machine is chosen a little stricter.

This is done to ensure that the insulation is not burnt. The circuit breaker will work for just over an hour when the current is exceeded by 13%( 36 A).And a little less than an hour with a deviation up by 45%( more than 45 A).During the specified time, the insulation should not suffer. Under the conditions considered, the current will not rise above 25 A, therefore, everything else means an accident on the line, which will lead to a multiple increase in value( much more than 45 A).Such a situation will trigger the protection of the automatic machine in a different, fast, pattern. And burnout insulation of the core will not occur.

If you connect the switches in the box to an increased nominal, there may be unpleasant consequences. Better to be safe. By the way, protection machines are cheap, you should not save. It is a different matter when it comes to differential residual current devices. These machines are on the branches of the cables leading to hazardous areas:

  1. Bathrooms and bathrooms, including outdoor sockets where the equipment is connected.
  2. Outdoor power distribution points, sockets near windows and entrance doors used for similar purposes.

According to RF standards, differential automata demonstrate a sensitivity of no more than 30 mA of leakage current. Because of the high cost, people will want to connect the dangerous branches in one. There is no direct prohibition, and the savings look significant. Example: we feed from a single differential automatic switch sockets for a bathroom and those that we use for work on the street( near the balcony).There are no direct bans on switching on, the price of this type of device is much higher than ordinary RCDs.

Where to locate an

switchboard. Often, a household switchboard hangs directly on a pole. There is an obvious fact, the requirements of the standards are reduced to the arrangement of a single knife switch available from the outside to turn off the object in case of fires and unforeseen situations. Proper wire insulation should provide comparative safety so that in a hurry a person does not get an electric shock.

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