The smaller cross-section of the copper wire allows higher currents to pass and, accordingly, is designed for increased power or load.

This feature is due to low resistance values, which makes it possible to use a copper core in the home in the presence of a voltage of not only 220 V, but also 380 Volts.

Electrical cable products differ in the type of insulation, cross-sectional diameter and material of the conductor.

These parameters determine not only the area of ​​use, but also the basic operating conditions.

The working element of any copper cable product is represented by a conductive core made from electrical copper.

In this case, several insulated cores are enclosed in one common shell. The outer covering is represented by the so-called “armor”, or a special protective screen.

The undeniable advantages of copper cable products are presented:

• high thermal conductivity;
• good current conductivity;
• plasticity and flexibility;
• resistance to kinking or twisting;
• ease of self-installation;
• duration of operation;
• stability to corrosive changes;
• minimal risk of fire.

Copper core

When choosing a cable product, you should pay attention to the markings. Laying in tunnels, in the open air and in the ground, is carried out with armored copper cable having durable double insulation. The mark “ng-LS” indicates the high fire safety ratings of the product.

It should be noted that single-core copper products are most often used when installing stationary wiring, and a multi-core conductor is in demand when it is necessary to use increased flexibility and elasticity, as well as resistance to vibration.

The cross-section of the copper wire is marked with the first number following the letter designation of the conductor type.

Wiring with copper conductors is used for internal and external installation in residential premises and office buildings, in industrial and production complexes, due to its high technical and quality characteristics.

Selection of wire cross-section

Copper is a reliable material with sufficient resistance to bending, a high level of electrical conductivity, and low susceptibility to corrosive changes. It is for this reason that, under conditions of the same level, a smaller cross-section of the copper core is provided compared to aluminum cable products.

The purchase of a copper-type electrical wire is carried out with a certain reserve cross-section, which reduces the risk of overheating as a result of an increase in load when connecting new volatile devices.

Cable VVGng 4x4 0.66 kV

It is important that the cross-section fully corresponds to the maximum load, as well as the current value for which automatic protective devices are designed.

The current value is one of the main indicators that influences the calculation of the wire cross-sectional area in copper cable products. A certain area determines the throughput of current over a long period of time. This parameter is called long-term permissible load. In this case, the cross-section of the copper core is the total cut area of ​​the central part conducting current to consumers.

Determined by the main dimensions measured using a caliper:

• for a circle - S = πd 2 / 4;
• for a square - S = a 2;
• for a rectangle - S = a × b;
• for a triangle - πr 2 / 3.

Power 16-core cable

Standard design symbols: radius (r), diameter (d), width (b) and length (a) of the section, as well as π = 3.14. As a rule, the standard cross-section of the input cable is 4-6 mm 2, the wiring for connecting the socket group is 2.5 mm 2, and the cross-sectional area for connecting the main lighting system is about 1.5 mm 2.

Before installing a copper conductor, it is necessary to take into account the specific operating conditions and the expected maximum current load that will flow through the electrical wiring for a long time.

Calculation of wire cross-section

To independently determine the rated current value, you need to calculate the maximum power of all connected volatile devices.

Given the already known indicators of the power consumed by the devices, the current strength is calculated.

Standard calculation formula for a single-phase 220 V network:

I = P × K and / U × cos φ

• P - total power indicators consumed by all connected electrical appliances (W);
• U - power supply voltage indicators (V);
• K and - simultaneity coefficient equal to 0.75;
• cos φ - indicator for connected household energy-dependent appliances.

Standard calculation formula for a 380 V electrical network:

I = P / √3 × U × cos φ

After calculating the current value, you can easily determine the cross-section of the copper wire using tabular data for this purpose.

You need to select the cable cross-sectional area taking into account the current value and the required power indicators, using the table and rounding the obtained values ​​up with the addition of 15-20% margin.

Cross-section of copper wire by power: table

Tabular data is the most convenient to use and most accurate, therefore experts recommend determining the cross-section of a copper cable product in accordance with the power indicators in the table.

For voltage 220 V		For voltage 380 V		Copper core cross-section
Power	Current	Power	Current
4.1 kW	19 A	10.5 kW	16 A	1.5 mm
5.9 kW	27 A	16.5 kW	25 A	2.5 mm
8.3 kW	38 A	19.8 kW	30 A	4.0 mm
10.1 kW	46 A	26.4 kW	40 A	6.0 mm
15.4 kW	70 A	33.0 kW	50 A	10.0 mm
18.7 kW	80 A	49.5 kW	75 A	16.0 mm
25.3 kW	115 A	59.4 kW	90 A	25.0 mm
29.7 kW	135 A	75.9 kW	115 A	35.0 mm
38.5 kW	175 A	95.7 kW	145 A	50.0 mm
47.2 kW	215 A	118.8 kW	180 A	70.0 mm
57.2 kW	265 A	145.2 kW	220 A	95.0 mm
66.0 kW	300 A	171.6 kW	260 A	120 mm

How to determine the cross-section for a stranded wire?

Stranded copper wires are conductors whose cross-section is represented by several cores, which in some brands of cable products are intertwined with each other. any stranded wire is calculated using the standard formula S = π × d²/4.

In this case, the total cross-sectional area of ​​a copper cable product will be the sum of the cross-sectional area of ​​all its cores.

An assessment of the load capacity of a stranded wire can be made without measuring the diameter of each individual conductor.

In this case, you need to measure the overall diameter of the multi-core cable product, and then use the standard increase factor of 0.91 in the formula.

The diameter of copper wires can be measured using a caliper or a micrometer.

Maximum flexibility and a high level of elasticity are observed in copper conductors, the cores of which are woven into a dense thread.

As a result of the use of special terminals, the connection of multi-core conductors acquires high reliability and lower current resistance, but in high-frequency electrical circuits the use of such cable products is limited.

When designing the circuit of any electrical installation and installation, choosing the cross-section of wires and cables is a mandatory step. In order to correctly select the power wire of the required cross-section, it is necessary to take into account the maximum consumption.

Wire cross-section is measured in square millimeters or "squares". Each “square” of aluminum wire is capable of passing through itself for a long time, heating up to permissible limits, a maximum of only 4 amperes, and copper wires 10 amperes of current. Accordingly, if some electrical consumer consumes power equal to 4 kilowatts (4000 watts), then at a voltage of 220 volts the current strength will be equal to 4000/220 = 18.18 amperes and to power it it is enough to supply electricity to it with a copper wire with a cross-section of 18.18/ 10=1.818 square. True, in this case the wire will work to the limit of its capabilities, so you should take a margin of at least 15% for the cross-section. We get 2.091 squares. And now we will select the nearest wire of standard cross-section. Those. We must conduct wiring to this consumer with a copper wire with a cross-section of 2 square millimeters, called the current load. Current values ​​can be easily determined by knowing the rated power of consumers using the formula: I = P/220. The aluminum wire will be correspondingly 2.5 times thicker.

Based on the calculation of sufficient mechanical strength, open power wiring is usually carried out with a wire with a cross-section of at least 4 square meters. mm. If you need to know with greater accuracy the long-term permissible current load for copper wires and cables, you can use the tables.

Copper conductors of wires and cables
	Voltage, 220 V		Voltage, 380 V
	current, A	power, kWt	current, A	power, kWt
1,5	19	4,1	16	10,5
2,5	27	5,9	25	16,5
4	38	8,3	30	19,8
6	46	10,1	40	26,4
10	70	15,4	50	33,0
16	85	18,7	75	49,5
25	115	25,3	90	59,4
35	135	29,7	115	75,9
50	175	38,5	145	95,7
70	215	47,3	180	118,8
95	260	57,2	220	145,2
120	300	66,0	260	171,6

Aluminum conductors of wires and cables
Cross-section of current-carrying conductor, mm.	Voltage, 220 V		Voltage, 380 V
	current, A	power, kWt	current, A	power, kWt
2,5	20	4,4	19	12,5
4	28	6,1	23	15,1
6	36	7,9	30	19,8
10	50	11,0	39	25,7
16	60	13,2	55	36,3
25	85	18,7	70	46,2
35	100	22,0	85	56,1
50	135	29,7	110	72,6
70	165	36,3	140	92,4
95	200	44,0	170	112,2
120	230	50,6	200	132,0

Permissible continuous current for wires and cords with rubber and polyvinyl chloride insulation with copper conductors, for example
Cross-section of current-carrying conductor, mm.	Open
		Two single-core	Three single-core	Four single-core	One two-wire	One three-wire
0,5	11	-	-	-	-	-
0,75	15	-	-	-	-	-
1	17	16	15	14	15	14
1,2	20	18	16	15	16	14,5
1,5	23	19	17	16	18	15
2	26	24	22	20	23	19
2,5	30	27	25	25	25	21
3	34	32	28	26	28	24
4	41	38	35	30	32	27
5	46	42	39	34	37	31
6	50	46	42	40	40	34
8	62	54	51	46	48	43
10	80	70	60	50	55	50
16	100	85	80	75	80	70
25	140	115	100	90	100	85
35	170	135	125	115	125	100
50	215	185	170	150	160	135
70	270	225	210	185	195	175
95	330	275	255	225	245	215
120	385	315	290	260	295	250
150	440	360	330	-	-	-
185	510	-	-	-	-	-
240	605	-	-	-	-	-
300	695	-	-	-	-	-
400	830	-	-	-	-	-

Permissible continuous current for wires and cords with rubber and polyvinyl chloride insulation with aluminum conductors
Cross-section of current-carrying conductor, mm.	Open	Current, A, for wires laid in one pipe
		Two single-core	Three single-core	Four single-core	One two-wire	One three-wire
2	21	19	18	15	17	14
2,5	24	20	19	19	19	16
3	27	24	22	21	22	18
4	32	28	28	23	25	21
5	36	32	30	27	28	24
6	39	36	32	30	31	26
8	46	43	40	37	38	32
10	60	50	47	39	42	38
16	75	60	60	55	60	55
25	105	85	80	70	75	65
35	130	100	95	85	95	75
50	165	140	130	120	125	105
70	210	175	165	140	150	135
95	255	215	200	175	190	165
120	295	245	220	200	230	190
150	340	275	255	-	-	-
185	390	-	-	-	-	-
240	465	-	-	-	-	-
300	535	-	-	-	-	-
400	645	-	-	-	-	-

Permissible continuous current for wires with copper conductors with rubber insulation in metal protective sheaths and cables with copper conductors with rubber insulation in lead, polyvinyl chloride, Nairite or rubber casing, armored and unarmored
Cross-section of current-carrying conductor, mm.	Current*, A, for wires and cables
	single-core		two-wire			three-wire
	when laying
	in the air	in the air		in the ground	in the air		in the ground
1,5	23	19		33	19		27
2,5	30	27		44	25		38
4	41	38		55	35		49
6	50	50		70	42		60
10	80	70		105	55		90
16	100	90		135	75		115
25	140	115		175	95		150
35	170	140		210	120		180
50	215	175		265	145		225
70	270	215		320	180		275
95	325	260		385	220		330
120	385	300		445	260		385
150	440	350		505	305		435
185	510	405		570	350		500
240	605	-		-	-		-

* Currents refer to cables and wires with and without a neutral core.

Permissible continuous current for cables with aluminum conductors with rubber or plastic insulation in lead, polyvinyl chloride and rubber sheaths, armored and unarmored
Cross-section of current-carrying conductor, mm.	Current, A, for wires and cables
	single-core		two-wire			three-wire
	when laying
	in the air	in the air		in the ground	in the air		in the ground
2,5	23	21		34	19		29
4	31	29		42	27		38
6	38	38		55	32		46
10	60	55		80	42		70
16	75	70		105	60		90
25	105	90		135	75		115
35	130	105		160	90		140
50	165	135		205	110		175
70	210	165		245	140		210
95	250	200		295	170		255
120	295	230		340	200		295
150	340	270		390	235		335
185	390	310		440	270		385
240	465	-		-	-		-

Permissible continuous currents for four-core cables with plastic insulation for voltages up to 1 kV can be selected according to this table as for three-core cables, but with a coefficient of 0.92.

Summary table of wire cross-sections, current, power and load characteristics
Cross-section of copper conductors of wires and cables, sq. mm	Permissible continuous load current for wires and cables, A	Rated current of the circuit breaker, A	Maximum current of the circuit breaker, A	Maximum single-phase load power at U=220 V	Characteristics of an approximate single-phase household load
1,5	19	10	16	4,1	lighting and alarm group
2,5	27	16	20	5,9	socket groups and electric floors
4	38	25	32	8,3	water heaters and air conditioners
6	46	32	40	10,1	electric stoves and ovens
10	70	50	63	15,4	input supply lines

The table shows data based on the PUE for selecting cross-sections of cable and wire products, as well as rated and maximum possible currents of circuit breakers for single-phase household loads most often used in everyday life.

We hope this information was useful to you. We remind you that from us you can buy excellent quality at a low price.

Standard apartment wiring is calculated for a maximum current consumption at a continuous load of 25 amperes (the circuit breaker that is installed at the entrance of wires into the apartment is also selected for this current strength) and is carried out with copper wire with a cross-section of 4.0 mm 2, which corresponds to a wire diameter of 2.26 mm and load power up to 6 kW.

According to the requirements of clause 7.1.35 of the PUE the cross-section of the copper core for residential electrical wiring must be at least 2.5 mm 2, which corresponds to a conductor diameter of 1.8 mm and a load current of 16 A. Electrical appliances with a total power of up to 3.5 kW can be connected to such electrical wiring.

What is wire cross-section and how to determine it

To see the cross-section of the wire, just cut it across and look at the cut from the end. The cut area is the cross-section of the wire. The larger it is, the more current the wire can transmit.

As can be seen from the formula, the cross-section of the wire is light according to its diameter. It is enough to multiply the diameter of the wire core by itself and by 0.785. For the cross-section of a stranded wire, you need to calculate the cross-section of one core and multiply by their number.

The diameter of the conductor can be determined using a caliper with an accuracy of 0.1 mm or a micrometer with an accuracy of 0.01 mm. If there are no instruments at hand, then an ordinary ruler will help out.

Section selection
copper wire electrical wiring by current strength

The magnitude of the electric current is indicated by the letter “ A" and is measured in Amperes. When choosing, a simple rule applies: The larger the cross-section of the wire, the better, so the result is rounded up.

Table for selecting the cross-section and diameter of copper wire depending on the current strength
Maximum current, A	1,0	2,0	3,0	4,0	5,0	6,0	10,0	16,0	20,0	25,0	32,0	40,0	50,0	63,0
Standard section, mm 2	0,35	0,35	0,50	0,75	1,0	1,2	2,0	2,5	3,0	4,0	5,0	6,0	8,0	10,0
Diameter, mm	0,67	0,67	0,80	0,98	1,1	1,2	1,6	1,8	2,0	2,3	2,5	2,7	3,2	3,6

The data I have provided in the table is based on personal experience and guarantees reliable operation of electrical wiring under the most unfavorable conditions of its installation and operation. When choosing a wire cross-section based on the current value, it does not matter whether it is alternating current or direct current. The magnitude and frequency of the voltage in the electrical wiring also does not matter; it can be the on-board network of a DC car at 12 V or 24 V, an aircraft at 115 V with a frequency of 400 Hz, electrical wiring 220 V or 380 V with a frequency of 50 Hz, a high-voltage power line at 10,000 IN.

If the current consumption of an electrical appliance is unknown, but the supply voltage and power are known, then the current can be calculated using the online calculator below.

It should be noted that at frequencies above 100 Hz, a skin effect begins to appear in wires when electric current flows, which means that with increasing frequency, the current begins to “press” against the outer surface of the wire and the actual cross-section of the wire decreases. Therefore, the choice of wire cross-section for high-frequency circuits is carried out according to different laws.

Determining the load capacity of 220 V electrical wiring
made of aluminum wire

In houses built a long time ago, electrical wiring is usually made of aluminum wires. If connections in junction boxes are made correctly, the service life of aluminum wiring can be one hundred years. After all, aluminum practically does not oxidize, and the service life of electrical wiring will be determined only by the service life of the plastic insulation and the reliability of the contacts at the connection points.

In the case of connecting additional energy-intensive electrical appliances in an apartment with aluminum wiring, it is necessary to determine by the cross-section or diameter of the wire cores its ability to withstand additional power. Using the table below, this is easy to do.

If your apartment wiring is made of aluminum wires and there is a need to connect a newly installed socket in a junction box with copper wires, then such a connection is made in accordance with the recommendations of the article Connecting aluminum wires.

Calculation of electrical wire cross-section
according to the power of connected electrical appliances

To select the cross-section of cable wire cores when laying electrical wiring in an apartment or house, you need to analyze the fleet of existing electrical household appliances from the point of view of their simultaneous use. The table provides a list of popular household electrical appliances indicating the current consumption depending on the power. You can find out the power consumption of your models yourself from the labels on the products themselves or data sheets; often the parameters are indicated on the packaging.

If the current consumed by an electrical appliance is unknown, it can be measured using an ammeter.

Table of power consumption and current for household electrical appliances
at supply voltage 220 V

Typically, the power consumption of electrical appliances is indicated on the housing in watts (W or VA) or kilowatts (kW or kVA). 1 kW=1000 W.

Table of power consumption and current for household electrical appliances
Household electrical appliance	Power consumption, kW (kVA)	Current consumption, A	Current consumption mode
Incandescent light bulb	0,06 – 0,25	0,3 – 1,2	Constantly
Electric kettle	1,0 – 2,0	5 – 9	Up to 5 minutes
Electric stove	1,0 – 6,0	5 – 60	Depends on operating mode
Microwave	1,5 – 2,2	7 – 10	Periodically
Electric meat grinder	1,5 – 2,2	7 – 10	Depends on operating mode
Toaster	0,5 – 1,5	2 – 7	Constantly
Grill	1,2 – 2,0	7 – 9	Constantly
Coffee grinder	0,5 – 1,5	2 – 8	Depends on operating mode
Coffee maker	0,5 – 1,5	2 – 8	Constantly
Electric oven	1,0 – 2,0	5 – 9	Depends on operating mode
Dishwasher	1,0 – 2,0	5 – 9
Washing machine	1,2 – 2,0	6 – 9	Maximum from the moment of switching on until the water is heated
Dryer	2,0 – 3,0	9 – 13	Constantly
Iron	1,2 – 2,0	6 – 9	Periodically
Vacuum cleaner	0,8 – 2,0	4 – 9	Depends on operating mode
Heater	0,5 – 3,0	2 – 13	Depends on operating mode
Hair dryer	0,5 – 1,5	2 – 8	Depends on operating mode
Air conditioner	1,0 – 3,0	5 – 13	Depends on operating mode
Desktop computer	0,3 – 0,8	1 – 3	Depends on operating mode
Power tools (drill, jigsaw, etc.)	0,5 – 2,5	2 – 13	Depends on operating mode

Current is also consumed by the refrigerator, lighting fixtures, radiotelephone, chargers, and TV in standby mode. But in total this power is no more than 100 W and can be ignored in calculations.

If you turn on all the electrical appliances in the house at the same time, you will need to select a wire cross-section capable of passing a current of 160 A. You will need a finger-thick wire! But such a case is unlikely. It’s hard to imagine that someone is capable of grinding meat, ironing, vacuuming and drying hair at the same time.

Calculation example. You got up in the morning, turned on the electric kettle, microwave, toaster and coffee maker. The current consumption will accordingly be 7 A + 8 A + 3 A + 4 A = 22 A. Taking into account the switched on lighting, refrigerator and, in addition, for example, a TV, the current consumption can reach 25 A.

for 220 V network

You can select the wire cross-section not only by the current strength, but also by the amount of power consumed. To do this, you need to make a list of all electrical appliances planned to be connected to a given section of electrical wiring, and determine how much power each of them consumes separately. Next, add up the data obtained and use the table below.

for 220 V network
Electrical appliance power, kW (kVA)	0,1	0,3	0,5	0,7	0,9	1,0	1,2	1,5	1,8	2,0	2,5	3,0	3,5	4,0	4,5	5,0	6,0
Standard section, mm 2	0,35	0,35	0,35	0,5	0,75	0,75	1,0	1,2	1,5	1,5	2,0	2,5	2,5	3,0	4,0	4,0	5,0
Diameter, mm	0,67	0,67	0,67	0,5	0,98	0,98	1,13	1,24	1,38	1,38	1,6	1,78	1,78	1,95	2,26	2,26	2,52

If there are several electrical appliances and for some the current consumption is known, and for others the power, then you need to determine the wire cross-section for each of them from the tables, and then add up the results.

Selecting the cross-section of copper wire according to power
for the car's on-board network 12 V

If, when connecting additional equipment to the vehicle’s on-board network, only its power consumption is known, then the cross-section of the additional electrical wiring can be determined using the table below.

Table for choosing the cross-section and diameter of copper wire according to power for vehicle on-board network 12 V
Electrical appliance power, watt (BA)	10	30	50	80	100	200	300	400	500	600	700	800	900	1000	1100	1200
Standard section, mm 2	0,35	0,5	0,75	1,2	1,5	3,0	4,0	6,0	8,0	8,0	10	10	10	16	16	16
Diameter, mm	0,67	0,5	0,8	1,24	1,38	1,95	2,26	2,76	3,19	3,19	3,57	3,57	3,57	4,51	4,51	4,51

Selecting the wire cross-section for connecting electrical appliances
to a three-phase network 380 V

When operating electrical appliances, for example, an electric motor, connected to a three-phase network, the consumed current no longer flows through two wires, but through three and, therefore, the amount of current flowing in each individual wire is somewhat less. This allows you to use a smaller cross-section wire to connect electrical appliances to a three-phase network.

To connect electrical appliances to a three-phase network with a voltage of 380 V, for example an electric motor, the wire cross-section for each phase is taken 1.75 times smaller than for connecting to a single-phase 220 V network.

Attention, when choosing a wire cross-section for connecting an electric motor based on power, it should be taken into account that the nameplate of the electric motor indicates the maximum mechanical power that the motor can create on the shaft, and not the electrical power consumed. The electrical power consumed by the electric motor, taking into account efficiency and cos φ, is approximately two times greater than that created on the shaft, which must be taken into account when choosing the wire cross-section based on the motor power indicated in the plate.

For example, you need to connect an electric motor that consumes power from a 2.0 kW network. The total current consumption of an electric motor of such power in three phases is 5.2 A. According to the table, it turns out that a wire with a cross-section of 1.0 mm 2 is needed, taking into account the above 1.0 / 1.75 = 0.5 mm 2. Therefore, to connect a 2.0 kW electric motor to a three-phase 380 V network, you will need a three-core copper cable with a cross-section of each core of 0.5 mm 2.

It is much easier to choose the wire cross-section for connecting a three-phase motor based on the current consumption, which is always indicated on the nameplate. For example, in the nameplate shown in the photograph, the current consumption of a motor with a power of 0.25 kW for each phase at a supply voltage of 220 V (motor windings are connected in a delta pattern) is 1.2 A, and at a voltage of 380 V (motor windings are connected in a delta pattern) "star" circuit) is only 0.7 A. Taking the current indicated on the nameplate, according to the table for selecting the wire cross-section for apartment wiring, select a wire with a cross-section of 0.35 mm 2 when connecting the electric motor windings according to the "triangle" or 0.15 mm pattern 2 when connected in a star configuration.

About choosing a cable brand for home wiring

Making apartment electrical wiring from aluminum wires at first glance seems cheaper, but operating costs due to low reliability of contacts over time will be many times higher than the costs of electrical wiring made from copper. I recommend making the wiring exclusively from copper wires! Aluminum wires are indispensable when laying overhead electrical wiring, as they are light and cheap and, when properly connected, serve reliably for a long time.

Which wire is better to use when installing electrical wiring, single-core or stranded? From the point of view of the ability to conduct current per unit of cross-section and installation, single-core is better. So for home wiring you only need to use solid wire. Stranded allows multiple bends, and the thinner the conductors in it, the more flexible and durable it is. Therefore, stranded wire is used to connect non-stationary electrical appliances to the electrical network, such as an electric hair dryer, an electric razor, an electric iron and all the others.

After deciding on the cross-section of the wire, the question arises about the brand of cable for electrical wiring. The choice here is not great and is represented by only a few brands of cables: PUNP, VVGng and NYM.

PUNP cable since 1990, in accordance with the decision of Glavgosenergonadzor “On the ban on the use of wires such as APVN, PPBN, PEN, PUNP, etc., produced according to TU 16-505. 610-74 instead of APV, APPV, PV and PPV wires according to GOST 6323-79*" is prohibited for use.

Cable VVG and VVGng - copper wires in double polyvinyl chloride insulation, flat shape. Designed for operation at ambient temperatures from −50°С to +50°С, for wiring inside buildings, outdoors, in the ground when laid in tubes. Service life up to 30 years. The letters “ng” in the brand designation indicate the non-flammability of the wire insulation. Two-, three- and four-core wires are available with core cross-sections from 1.5 to 35.0 mm 2 . If in the cable designation there is a letter A (AVVG) before VVG, then the conductors in the wire are aluminum.

The NYM cable (its Russian analogue is the VVG cable), with copper cores, round in shape, with non-flammable insulation, complies with the German standard VDE 0250. Technical characteristics and scope of application are almost the same as the VVG cable. Two-, three- and four-core wires are available with core cross-sections from 1.5 to 4.0 mm 2 .

As you can see, the choice for laying electrical wiring is not large and is determined depending on what shape the cable is more suitable for installation, round or flat. A round-shaped cable is more convenient to lay through walls, especially if the connection is made from the street into the room. You will need to drill a hole slightly larger than the diameter of the cable, and with a larger wall thickness this becomes relevant. For internal wiring, it is more convenient to use a VVG flat cable.

Parallel connection of electrical wiring wires

There are hopeless situations when you urgently need to lay wiring, but there is no wire of the required cross-section available. In this case, if there is a wire with a smaller cross-section than necessary, then the wiring can be made from two or more wires, connecting them in parallel. The main thing is that the sum of the sections of each of them is not less than the calculated one.

For example, there are three wires with a cross section of 2, 3 and 5 mm 2, but according to calculations, 10 mm 2 is needed. Connect them all in parallel and the wiring will handle up to 50 amps. Yes, you yourself have repeatedly seen the parallel connection of a large number of thin conductors to transmit large currents. For example, welding uses a current of up to 150 A and in order for the welder to control the electrode, a flexible wire is needed. It is made from hundreds of thin copper wires connected in parallel. In a car, the battery is also connected to the on-board network using the same flexible stranded wire, since when starting the engine, the starter consumes current from the battery up to 100 A. And when installing and removing the battery, the wires must be taken to the side, that is, the wire must be flexible enough .

The method of increasing the cross-section of an electrical wire by connecting several wires of different diameters in parallel can be used only as a last resort. When laying home electrical wiring, it is permissible to connect in parallel only wires of the same cross-section taken from the same reel.

Online calculators for calculating the cross-section and diameter of a wire

Using the online calculator presented below, you can solve the inverse problem - determine the diameter of the conductor by cross-section.

How to calculate the cross-section of a stranded wire

Stranded wire, or as it is also called stranded or flexible, is a single-core wire twisted together. To calculate the cross-section of a stranded wire, you must first calculate the cross-section of one wire, and then multiply the resulting result by their number.

Let's look at an example. There is a multi-core flexible wire, in which there are 15 cores with a diameter of 0.5 mm. The cross-section of one core is 0.5 mm × 0.5 mm × 0.785 = 0.19625 mm 2, after rounding we get 0.2 mm 2. Since we have 15 wires in the wire, to determine the cable cross-section we need to multiply these numbers. 0.2 mm 2 ×15=3 mm 2. It remains to determine from the table that such a stranded wire will withstand a current of 20 A.

You can estimate the load capacity of a stranded wire without measuring the diameter of an individual conductor by measuring the total diameter of all twisted wires. But since the wires are round, there are air gaps between them. To eliminate the gap area, you need to multiply the result of the wire cross-section obtained from the formula by a factor of 0.91. When measuring the diameter, you need to make sure that the stranded wire does not flatten.

Let's look at an example. As a result of measurements, the stranded wire has a diameter of 2.0 mm. Let's calculate its cross-section: 2.0 mm × 2.0 mm × 0.785 × 0.91 = 2.9 mm 2. Using the table (see below), we determine that this stranded wire will withstand a current of up to 20 A.

Of the cross-sections of current-carrying conductors of a copper wire indicated in the question, a wire with a cross-section of 1 square millimeter is perhaps the most rarely used. This wire can be used to make internal switching of a chandelier or lamp; for each light bulb in the chandelier it will be more than enough, because individually they rarely exceed 500 Watts. With a wire of 1 square millimeter, today you can also install a lighting line for internal electrical wiring in which energy-saving or LED lamps will be used; their power is low and a wire of one square is enough. Why in a private house? Yes, because the wiring of apartments is still done according to the PUE and must have a cross-section of at least 1.5 square meters. The total power that the wire cross-section will withstand 1 square millimeter - 2200 Watts (2.2 Kilowatts) (10 Amps) You can connect any device whose power does not exceed this value. For example, it is not critical to connect a hair dryer, computer, TV, video set-top box, power supply for video surveillance systems, mixer... When determining the power characteristics of a device, you must first of all refer to its passport data indicated in the passport plate (usually stuck on the device in an inconspicuous place)

Wire with a cross-section of 1.5 is usually used in lighting, although the power reserve in the lighting line is not very bad. By the way, the maximum permissible load on the wire should not be taken as standard; there should always be a reserve of power, about 10 percent. In this case, your wire will never heat up even if all consumers are turned on for a long time, especially the connection points, which are the weakest link in any electrical circuit.

Below is a table of the ratios of the cross-sectional area of ​​the core, permissible current and power. So these are the peak values, subtract 10 percent from them and your wiring will not overheat with any installation method - closed or open wiring.

As you noticed, the value of current and power for different voltages is also different. The question does not indicate the voltage, so I give it for both a 220 Volt network and a 380 Volt network.

So what can we connect in a 220 Volt household network to the wire in -

- 1.5 square- 3500 Watt. This can be at the same time an electric kettle of 2 Kilowatts + a Hairdryer of 250 Watts + a mixer of 250 Watts + an iron of 1 Kilowatt.

- 2.5 square- 5500 Watt. This can be at the same time, all the same, a 2 Kilowatt electric kettle + a 250 Watt hair dryer + a 250 Watt mixer + a 1 Kilowatt iron + a 500 Watt TV + a 1400 Watt vacuum cleaner.

This is just a calculation of power with a margin based on the capabilities of the wire.

You may ask why I didn’t give the number of consumers and their power for a wire with a cross-section of 2 square meters? Yes, because the main cross-section of copper wires is 0.75; 1; 1.5; 2.5; 4; 6; 10 squares. I do not exclude that for a narrow purpose a copper wire with a cross-section of 2 square meters. mm. and there is, but not in retail sale.

The question emphasizes “..in my own words..” but nevertheless, for educational purposes, I will give a table of the ratios of the power of electrical appliances to the current consumed, so it will be easier to correlate the existing device, its power (or the total power of several devices) and the current consumed by them and the corresponding cross-section of the copper core.

Seeing this sign and knowing that 1 square millimeter of wire can withstand a current of 10 Amps, we can easily calculate the maximum possible power for our wire.

For example, an electric kettle with a power of 1500 Watt consumes a current of 6.8 Amperes. It turns out that for a wire with a cross-section of 1 square, powering such a kettle will not be critical, even with a good power reserve. But for a kettle with a power of 2000 Watts, a wire of the same cross-section will already lie in the “red zone” of the permissible load, and its constant use for this purpose is unacceptable; you need to take a larger cross-section.

Calculations made independently by hand are not always accurate for correctly determining the long-term permissible loads on the electrical network.

The load table for the cable cross-section belongs to the category of refined calculations, and allows you to correctly determine the choice of external or external wiring.

Core cross-section

The core of a cable product is a conductive copper or aluminum wire core protected by insulating material.

The nominal cross-sectional values ​​of the conductor are in the conductive part of the cable product, and are indicated in the markings on the insulation.

Independent calculation of the actual cross-section of the core is relevant in several situations:

• checking the cable product for compliance with the actual cross-sectional indicators declared by the manufacturer;
• assessment of the quality and technical characteristics of an unmarked cable product.

Standard formula for round cable products no more than 10 mm 2:

S= πD 2 /4

• π - number “Pi” equal to 3.14;
• D - results of measurements of the core diameter in mm;
• S - required indicators of the cross-section of the cable core in mm 2.

In multi-wire cable products, the cross-section of one core is measured, after which the result is multiplied by the number of all elements. The calculation of segmented cables is more complex.

Calculation of the cross-section of a single-wire conductor is most often carried out using a caliper, and a multi-wire cable product - with a micrometer.

Wire based on different materials

Electrical cable products can be represented by wires with aluminum or copper conductors. The second option is more preferable due to lower resistance and durability. However, it is the aluminum cable that is more affordable.

Aluminum power cable 4-core cross-section 38 sq mm

A cable product consists of several main elements:

• cores - parts responsible for conducting electric current;
• insulation - protective cable surface of dielectric type.

Monolithic cores are represented by one wire, and composite cores are represented by several wires twisted into a bundle, which has a positive effect on their flexibility. The connection of the main elements of electrical wiring is most often carried out with special clamps - terminals.

Copper type

The undeniable advantages of a cable product with a copper conductor are:

• insignificant indicators of electrical resistance;
• high level of flexibility;
• mechanical stability;
• Suitable for soldering and tinning;
• ease of welding and twisting.

The oxidized surface on the contacts has low contact resistance, and during installation and crimping there is no need to lubricate the surfaces, which makes working with the material easier. The most popular brands:

• PV- single-core wire with a cross section of 0.5-95 mm 2;
• PPV- two- or three-core wire with a cross section of 0.75-4.0 mm 2;
• ETC- single-core with a cross section of 0.75-120 mm 2.

The most important disadvantage of wiring with a copper core is the high cost of the source material, and, accordingly, of all cable products containing copper.

Aluminum type

The main advantages of a cable product with an aluminum conductor are presented:

• lower weight of installed electrical wiring;
• wide selection and affordable prices.

It should be noted that the electrical conductivity of aluminum is one and a half times lower than that of a copper cable, and the material, which is amorphous in its characteristics, can “leak” from the crimps during long-term operation.

Aluminum cable insulated

Over time, the aluminum surface oxidizes, and the result of this natural process is a noticeable loss of current conductivity. The most popular brands:

• Automatic reclosing
• APPV- two- or three-core wire with a cross section of 2.5-6.0 mm 2;
• APR- single-core wire with a cross section of 2.5-120 mm 2;
• PRN- single-core wire with a cross section of 2.5-120 mm 2.

Some difficulties arise when installing aluminum cable products, which is explained by the need to use gas welding and soldering using fluxes and solders.

The design and installation of any electrical circuit involves the correct choice of cable cross-section with mandatory consideration of the maximum power consumption or load.

The wire cross-section measured in mm2 or “squares” has different highest throughput over a long time, and also differs in heating period:

• with aluminum core - 4.0 A;
• with copper core - 10 A.

For example, a energy-dependent consumer using 4 kW or 4000 W in a single-phase 220 V network needs 4000 / 220 = 18.18 A + 15%, which is provided by a wire with a 2.0 mm 2 copper core.

When using an aluminum conductor, the core of the mounted cable product must have a thickness of at least 4.5-5.0 mm 2.

Current load values ​​are most often determined in accordance with the power of volatile consumers declared in the product passport, as well as according to the formula: I = P/220.

Table of dependence of wire cross-section on load

The most popular and common wire cross-sectional indicators currently used in practice are cable core areas of 0.75, 1.5, 2.5 and 4.0 mm 2 . When choosing a section depending on the load parameters, it is advisable to use standard tabular data.

Section

Open wiring

Closed wiring

Aluminum core

Copper core

Aluminum core

Copper core

Current

Power

Current

Power

Current

Power

Current

Power

380

220

380

220

380

220

380

220

0.5mm 2

–

–

–

11A

–

2.4V

–

–

–

–

–

–

0.75 mm 2

–

–

–

15A

–

3.3V

–

–

–

–

–

–

1.0 mm 2

–

–

–

17A

6.4V

3.7V

–

–

–

14A

5.3V

3.0V

1.5 mm 2

–

–

–

23A

8.7V

5.0V

–

–

–

15A

5.7V

3.3V

2.0 mm 2

21A

7.9V

4.6V

26A

9.8V

5.7V

14A

5.3V

3.0V

19A

7.2V

4.1V

2.5 mm 2

24A

9.1V

5.2V

30A

11V

6.6V

16A

6.0V

3.5V

21A

7.9V

4.6V

4.0 mm 2

32A

12V

7.0V

41A

15V

9.0V

21A

7.9V

4.6V

27A

10V

5.9V

6.0 mm 2

39V

14V

8.5V

50A

19V

11V

26A

9.8V

5.7V

34A

12V

7.4V

10.0 mm 2

60V

22V

13V

80A

30V

17V

38A

14V

8.3V

50A

19V

11V

16.0 mm 2

75V

28V

16V

100A

38V

22V

55A

20V

12V

80A

30V

17V

25.0 mm 2

105V

39V

23V

140A

53V

30V

65A

24V

14V

100A

38V

22V

35.0 mm 2

130V

49V

28V

170A

64V

37V

75A

28V

16V

135A

51B

29V

A prerequisite for the correct selection of core cross-section in power cable products is taking into account the maximum current consumed in the load.

Only high-quality wires can withstand a sufficient load, so when choosing, you need to pay attention to the marking, which contains information about GOST and TU, the manufacturer and the type of cable product.

Along the entire length of the cable product, directly on the insulating layer, the manufacturer must indicate the brand of wire and its cross-section. If there is no information about even one of the listed parameters, it is recommended to refuse to purchase a cable product.