When you have to make repairs in an apartment or house, first of all, you should check the condition of the electrical wiring and determine the possibility of improving or replacing it. In the old house, aluminum wiring is being changed, the guaranteed service life of which does not exceed 20 years. This is done for the following reasons:
Copper wires for home electrical wiring
For internal and external wiring in an apartment or house, electrical wires and cables should be used.
To decide which one is better to choose in the store, you should be guided by the advice of the seller mainly in terms of prices. In all other respects, you first need to listen to what an experienced electrician will say, as well as familiarize yourself with the rules and regulations of electrical repairs.
There are differences between cable and wire, sometimes determined only by specification. The latter is an electrical product made of one or more insulated wires, twisted and placed in a light non-metallic sheath. With a cable, it is better, because it is more powerful, with insulated cores placed inside. It may also contain a core, shield, core, armor, or metal sheath. Each element is designed to operate the product in certain environmental conditions.
Electric wires are only allowed to be carried out in plastic pipes (HDPE and corrugations). This will require a lot of work and materials. They try to choose electrical wiring, focusing on price and cross-section. The wire is cheaper than the cable and it can be used for indoor laying in the premises. The cross section depends on the expected load. It is better to use copper as a conductor material.
The figure below shows copper and aluminum wires. They are easy to distinguish by color.
Copper and aluminum wires
Aluminum wire does not last long, deforms when tightened and has more resistance. However, it is cheaper, but over time this advantage will be lost due to its fragility.
The cross section of the electrical wiring is selected based on what power devices will be connected at the same time.
The current consumed by the load is determined by the formula:
P is nameplate power, W;
V is the voltage in the network, usually equal to 220 V.
For some appliances, it is necessary to take into account the reactive component of the electric current: refrigerator compressor, fluorescent lamp, tool motor. She is also involved in heating the wire. The total power consumption for them is determined by dividing its active component by cos φ, indicated in the instrument's passport or on its plate.
The permissible current for open wiring with a copper conductor is 10 A / mm 2, and for closed wiring - 6 A / mm 2. For aluminum, it is allowed to be 6 A / mm 2 and 4 A / mm 2, respectively. The currents of all consumers flowing through the wire are summed up, and the total load is determined.
Then, the required cross section is found along it, and a power margin is taken based on the connection of new electrical appliances. The selection of cross-sections of copper wires for current and voltage can be made using the following table.
Selection of the section of cables and wires for hidden wiring
| Cable core cross section, mm 2 | Cable core diameter | Copper wire | Aluminum conductor wiring | ||||
|---|---|---|---|---|---|---|---|
| Current, A | Power, kW at 220V | Power, kW at 380V | Current, A | Power, kW at 220V | Power, kW at 380V | ||
| 1 | 1.12 | 14 | 3 | 5.3 | x | x | x |
| 1.5 | 1.38 | 15 | 3.3 | 5.7 | x | x | x |
| 2 | 1.59 | 19 | 4.1 | 7.2 | 14 | 3 | 5.3 |
| 2.5 | 1.78 | 21 | 4.6 | 7.9 | 16 | 3.5 | 6 |
| 4 | 2.26 | 27 | 5.9 | 10 | 21 | 4.6 | 7.9 |
| 6 | 2.76 | 34 | 7.7 | 12 | 26 | 5.7 | 9.8 |
| 10 | 3.57 | 50 | 11 | 19 | 38 | 8.3 | 14 |
| 16 | 4.51 | 80 | 17 | 30 | 55 | 12 | 20 |
| 25 | 5.64 | 100 | 22 | 38 | 65 | 14 | 24 |
| 35 | 6.68 | 135 | 29 | 51 | 75 | 16 | 28 |
For lighting, the wire cross section is selected by 1.5 mm 2. It is connected to a 16 A machine. To sockets designed for higher loads, it is made to 2.5 mm 2, connected to a 25 A machine. A cable of 4 mm 2 or more is pulled to powerful electrical appliances. The cross section of the input to apartments or private houses should be made at least one step higher than that of the largest internal load.
When buying a cable, you should measure the diameters of the cores, since many manufacturers make them with large downward tolerances. As a result, the cross section may be lower than the calculated one.
It is important to consider the number of conductors in the cable. For the old system, two cores are enough, and for the new one, one more is required for grounding. To a chandelier with a two-gang switch, you will need a 4-core cable (the designation in the marking is 4x1.5).
With a long length in the wiring, voltage losses increase. They should not exceed 5%. The percentage of losses is found through the load moment, which is determined from the tables through the power multiplied by the cable length. When the cross section is calculated, the heating of the cable from the passing current is not taken into account, so the choice is made with a margin of about 20%.
If electrical cables are laid with a lot of bends in indoor and outdoor wiring, it is better to choose strands, each of which consists of a large number of thin wires. To connect to the terminals, it is necessary to press on the tips on them. Rigid cable consists of single cores. To ensure the required wiring capacity, it is not so important which brand of cable to use. The main requirement is to match the load of the consumer. In the house, the three-core version is most often used, where a ground wire is needed.
Imported NUM cables are very popular, shown in the figure below with a different number of cores.
Imported NUM wiring cable
The presence of two insulations provides its increased fire safety. Many opt for it, despite the higher price. On the street, other types are used instead, because he does not like sunlight. The weather resistance of the cable is determined by the properties of the outer sheath.
It is advisable to make a choice of an inexpensive, convenient and compact cable of the VVG brand for indoor and outdoor wiring.
Types of common cables
It can be used in wet and dry areas. Only underground laying is not recommended. The cable can be round and flat, there is no filler inside it. The cores are made with different colors and twisted together.
The power cable of the VVGng-P-LS brand for electrical wiring in an apartment and other households has the most diverse core designs: round, square, triangular, sector. Outwardly, it is similar to VVG, but its external insulation does not support combustion. The cross section of round conductors reaches 16 mm 2. Large sections are made sectorial, which saves metal. The cable can be used at increased voltage.
The choice of a multi-wire cable of the PVS brand with good flexibility is made mainly as a network wire for connecting household appliances. It is good to use for home wiring. It can be used on the street, but stranded wires corrode faster, and in the cold the insulation cracks when bent.
ShVVP - a flexible power cable with stranded cores is also used for household electrical appliances connected to networks with voltages up to 380 V. It is an analogue of PVA (they are similar in the figure above), but designed for smaller loads.
All listed cables are designed for open and hidden wiring. Their conductive wires have similar characteristics. Installation of hidden wiring is best done for reasons of convenience, since it does not clutter up the premises and does not impair the design. For an open one, it is important to choose the color of the outer sheath, but the wires are laid mainly in a corrugated pipe or cable channel.
The colors of the cable cores and wires for the electrical wiring are important for correct connections:
In street wiring for branching through the air, a self-supporting steel-aluminum cable of the SIP brand is used. The cores are insulated with weather-resistant polyethylene. The figure below shows a CIP cable (top) connected to a house entry cable. The connection between them is made with the help of punctures (circled in red circles). The figure on the right shows the connection of the meter.
SIP cable connection to the house
For street wiring with underground connection to the power grid, armored waterproof cables AVBShv and VBShv are used. The first letter A on all markings means that aluminum conductors are used. If it is absent, then copper.
The PUNP installation wire is one of the cheapest. It is better not to use it because of the poor quality of the insulation, which quickly loses its properties when heated. The wire is made with two or three cores. Products are produced flat, and they are used for lighting and power networks.
Wires for residential electrical wiring with rubber insulation are not recommended because of the fire hazard. They are designed for laying in different conditions:
Open wiring can be done with PPV and PPP wires.
Single-core wire PV1 or PV2 for wiring is mainly used for installation in switchboards. When large wire bends are needed, it is better to use the more expensive PV3 and PV4 with a flexible sheath.
For special conditions, for example, in a steam room, heat-resistant wires and cables for electrical wiring are used. PRKS wire with organosilicon insulation can withstand temperatures up to +180 0 C. If you need a multi-core cable, RKGM will do. It is also heat resistant and better suited for environments with up to 100% humidity.
When replacing part of the old wiring, aluminum wires are purchased. You can insert copper if you qualitatively connect the cores through a terminal block or a bolt with a nut. The wires are bent into rings and three anodized steel washers are laid around them.
Bolted connection of copper and aluminum wires
The disadvantage is the large dimensions of the connection, but still they are smaller than through the terminal block.
How to conduct electrical wiring yourself, you can learn from the video below.
The wiring of electricity in an apartment or house has its own nuances. Even professional electricians can make mistakes. It is important to correctly calculate and select cables and wires, since many of them are made for their intended purpose.
