The ability to choose the right cable cross-section can be useful to anyone over time, and you don’t have to be a qualified electrician to do this. By incorrectly calculating the cable, you can expose yourself and your property to serious risk - too thin wires will get very hot, which can lead to a fire.

Why do you need to calculate the cable cross-section?

First of all, carrying out this slightly complicated procedure is necessary to ensure the safety of both the premises itself and the people in it. Today, humanity has not invented a more convenient method of distributing and delivering electrical energy to the consumer, like through wires. People need the services of an electrician almost every day - someone needs to connect an outlet, someone needs to install a lamp, etc. From this it turns out that even such a seemingly insignificant procedure as installing a new lamp is associated with the operation of selecting the required cross-section . What then can we say about connecting an electric stove or water heater?

Failure to comply with the standards can lead to damage to the integrity of the wiring, which often causes a short circuit or even electric shock.

If you make a mistake when choosing a cable cross-section and purchase a cable with a smaller conductor area, this will lead to constant heating of the cable, which will cause destruction of its insulation. Naturally, all this negatively affects the life of the wiring - there are often cases when, a month after successful installation, the electrical wiring stopped working and specialist intervention was required.

It should be remembered that the electrical and fire safety in the building, and therefore the lives of the residents themselves, directly depends on the correctly selected cable cross-section.

Of course, every owner wants to save as much as possible, but you should not do this at the cost of your life, putting it at risk - after all, as a result of a short circuit, a fire may occur, which may well destroy all property.

To avoid this, before starting electrical installation work, you should select a cable of the optimal cross-section. For selection, several factors must be taken into account:

• the total number of electrical devices located in the room;
• the total power of all devices and the load they consume. To the obtained value you should add 20–30% “in reserve”;
• then, through simple mathematical calculations, convert the resulting value into the cross-section of the wire, taking into account the material of the conductor.

Attention! Due to lower electrical conductivity, wires with aluminum conductors must be purchased with a larger cross-section than copper ones.

What affects the heating of wires

If the wiring heats up during the operation of household appliances, then you should immediately take all necessary measures to eliminate this problem. There are many factors influencing the heating of wires, but the main ones include the following:

1. Insufficient cable cross-sectional area. To put it in accessible language, we can say this: the thicker the cable’s cores, the more current it can transmit without overheating. The value of this value is indicated in the marking of cable products. You can also measure the cross-section yourself using a caliper (you should make sure that the wire is not live) or by the type of wire.
2. Material from which the wire is made. Copper conductors transmit voltage better to the consumer and have lower resistance compared to aluminum conductors. Naturally, they heat up less.
3. Core type. The cable can be single-core (the core consists of one thick rod) or multi-core (the core consists of a large number of small wires). A multi-core cable is more flexible, but is significantly inferior to a single-core cable in terms of the permissible strength of the transmitted current.
4. Cable laying method. Tightly laid wires located in the pipe heat up noticeably more than open wiring.
5. Material and quality of insulation. Inexpensive wires, as a rule, have low quality insulation, which negatively affects their resistance to high temperatures.

How to calculate power consumption

You can calculate the approximate cable cross-section yourself - it is not necessary to seek the help of a qualified specialist. The data obtained as a result of the calculations can be used to purchase wires, however, the electrical installation work itself should be trusted only to an experienced person.

The sequence of actions when calculating the section is as follows:

1. A detailed list of all electrical appliances in the room is compiled.
2. The passport data of the power consumption of all found devices is established, after which the continuity of operation of a particular equipment is determined.
3. Having identified the value of power consumption from devices that operate constantly, you should sum this value by adding to it a coefficient equal to the value of electrical appliances that turn on periodically (that is, if the device will work only 30% of the time, then you should add a third of its power).
4. Next, we look for the obtained values ​​in a special table for calculating the wire cross-section. For greater guarantee, it is recommended to add 10-15% to the obtained power consumption value.

To determine the necessary calculations for selecting the cross-section of electrical wiring cables according to their power within the network, it is important to use data on the amount of electrical energy consumed by devices and current appliances.

At this stage, it is necessary to take into account a very important point - the data of electrically consumed devices does not give an exact, but an approximate, average value. Therefore, about 5% of the parameters specified by the equipment manufacturer must be added to this mark.

The majority of not the most competent and qualified electricians are confident in one simple truth - in order to correctly install electrical wires for lighting sources (for example, for lamps), it is necessary to take wires with a cross-section equal to 0.5 mm², for chandeliers - 1, 5 mm², and for sockets – 2.5 mm².

Only incompetent electricians think about this and think so. But what if, for example, a microwave, kettle, refrigerator and lighting operate simultaneously in the same room, which require wires with different cross-sections? This can lead to a variety of situations: short circuit, rapid damage to wiring and insulating layer, as well as fire (this is a rare case, but still possible).

Exactly the same not very pleasant situation can happen if a person connects a multicooker, a coffee maker and, say, a washing machine to the same outlet.

Features of calculating the power of hidden wiring

If the design documentation implies the use of hidden wiring, then it is necessary to purchase cable products “with a reserve” - about 20–30% should be added to the obtained value of the cable cross-section. This is done to avoid heating the cable during operation. The fact is that in conditions of cramped space and lack of air access, heating of the cable occurs much more intensely than when installing open wiring. If in closed channels it is planned to lay not one cable, but several at once, then the cross-section of each wire should be increased by at least 40%. It is also not recommended to tightly lay various wires - ideally, each cable should be contained in a corrugated pipe, which provides it with additional protection.

Important! It is by the value of power consumption that professional electricians are guided when choosing a cable cross-section, and only this method is correct.

How to calculate cable cross-sections by power

If the cable cross-section is sufficient, the electric current will pass to the consumer without causing heating. Why does heating occur? We will try to explain as clearly as possible. For example, a kettle with a power consumption of 2 kilowatts is plugged into the outlet, but the wire going to the outlet can only transmit a current of 1 kilowatt for it. The cable capacity is related to the resistance of the conductor - the greater it is, the less current can be transmitted through the wire. As a result of high resistance in the wiring, the cable heats up, gradually destroying the insulation.

With the appropriate cross-section, the electric current reaches the consumer in full, and the wire does not heat up. Therefore, when designing electrical wiring, you should take into account the power consumption of each electrical device. This value can be found from the technical data sheet for the electrical device or from the label affixed to it. By summing the maximum values ​​and using a simple formula:

and get the value of the total current.

Pn denotes the power of the electrical appliance indicated in the passport, 220 is the rated voltage.

For a three-phase system (380 V), the formula looks like this:

I=(P1+P2+....+Pn)/√3/380.

The resulting I value is measured in Amperes, and based on it, the appropriate cable cross-section is selected.

It is known that the throughput of a copper cable is 10 A/mm; for an aluminum cable the throughput is 8 A/mm.

For example, let’s calculate the cable cross-section for connecting a washing machine, the power consumption of which is 2400 W.

I=2400 W/220 V=10.91 A, rounding up we get 11 A.

11 A+5 A=16 A.

If we take into account that three-core cables are used in apartments and look at the table, then the value close to 16 A is 19 A, so to install a washing machine you will need a wire with a cross-section of at least 2 mm².

Table of cable cross-sections relative to current values

Current cross-section wire length of core(mm 2)		Current (A), for wires laid
	Open That		in one pipe
		two one- vein	three one- vein	four one- vein	one two- vein	one three- vein
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	-	-	-	-	-

How to choose conductor cross-sections

There are several more criteria that the cross-section of the wires used must meet:

1. Length of cable. The longer the wire, the greater the current loss observed in it. This again occurs as a result of an increase in resistance, which increases as the length of the conductor increases. This is especially noticeable when using aluminum wiring. When using copper wires to organize electrical wiring in an apartment, the length, as a rule, is not taken into account - a standard margin of 20–30% (for hidden wiring) is more than enough to compensate for possible increases in resistance associated with the length of the wire.
2. Type of wires used. There are 2 types of conductors used in household electricity supply - copper or aluminum based. Copper wires are of better quality and have less resistance, but aluminum wires are cheaper. In full compliance with the standards, aluminum wiring copes with its tasks no worse than copper, so you need to carefully weigh your choice before purchasing a wire.
3. Electrical panel configuration. If all the wires supplying consumers are connected to one circuit breaker, then it will be the weak point in the system. A heavy load will lead to heating of the terminal blocks, and non-compliance with the rating will lead to its constant operation. It is recommended to divide the electrical wiring into several “beams” with the installation of a separate machine.

In order to determine the exact data for choosing the cross-section of electrical wiring cables, it is necessary to take into account any, even the most insignificant parameters, such as:

1. Type and type of insulation of electrical wiring;
2. Length of sections;
3. Laying methods and options;
4. Features of temperature conditions;
5. Humidity level and percentage;
6. The maximum possible value of superheat;
7. The difference in the powers of all current receivers belonging to the same group. All these and many other indicators can significantly increase the efficiency and benefits of energy use on any scale. In addition, correct calculations will help avoid cases of overheating or rapid abrasion of the insulating layer.

In order to correctly determine the optimal cable cross-section for any human household needs, it is necessary in all general cases to use the standardized following rules:

• for all sockets that will be installed in the apartment, it is necessary to use wires with an appropriate cross-section of 3.5 mm²;
• for all spotlighting elements, it is necessary to use electrical wiring cables with a cross-section of 1.5 mm²;
• As for high-power devices, cables with a cross-section of 4-6 mm² should be used.

If some doubts arise during the installation or calculation process, it is better not to act blindly. The ideal option would be to refer to the appropriate table of calculations and standards.

Copper cable cross-section table

Cross-section of conductors (mm)	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
16	80	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	265	57,2	220	145,2
120	300	66	260	171,6

Aluminum cable cross-section table

Hello!

I have heard about some difficulties that arise when choosing equipment and connecting it (which outlet is needed for an oven, hob or washing machine). In order for you to quickly and easily solve this, as good advice, I suggest you familiarize yourself with the tables presented below.

Types of equipment	Included	What else is needed
	terminals
Email panel (independent)	terminals	cable supplied from the machine, with a margin of at least 1 meter (for connection to the terminals)
		Euro socket
Gas panel		gas hose, euro socket
Gas oven	cable and plug for electric ignition	gas hose, euro socket
Washing machine
Dishwasher	cable, plug, hoses about 1300mm. (drain, bay)	for connection to water, ¾ outlet or straight-through tap, Euro socket
Refrigerator, wine cabinet	cable, plug	Euro socket
Hood	cable, plug may not be included	corrugated pipe (at least 1 meter) or PVC box, Euro socket
Coffee machine, steamer, microwave oven	cable, plug	Euro socket

Types of equipment		Socket	Cable cross-section		Automatic + RCD⃰ in the panel
			Single phase connection	Three-phase connection
Dependent set: el. panel, oven	about 11 kW (9)		6mm² (PVS 3*6) (32-42)	4mm² (PVS 5*4) (25)*3	separate at least 25A (only 380V)
Email panel (independent)	6-15 kW (7)		up to 9 kW/4mm² 9-11 kW/6mm² 11-15KW/10mm² (PVS 4,6,10*3)	up to 15 kW/ 4mm² (PVS 4*5)	separate at least 25A
Email oven (independent)	about 3.5 - 6 kW	Euro socket	2.5mm²		not less than 16A
Gas panel		Euro socket	1.5mm²		16A
Gas oven		Euro socket	1.5mm²		16A
Washing machine	2.5 kW	Euro socket	2.5mm²		separate at least 16A
Dishwasher	2 kW	Euro socket	2.5mm²		separate at least 16A
Refrigerator, wine cabinet	less than 1KW	Euro socket	1.5mm²		16A
Hood	less than 1KW	Euro socket	1.5mm²		16A
Coffee machine, steamer	up to 2 kW	Euro socket	1.5mm²		16A

⃰ Residual current device

Electrical connection at voltage 220V/380V

Types of equipment	Maximum power consumption	Socket	Cable cross-section		Automatic + RCD⃰ in the panel
			Single phase connection	Three-phase connection
Dependent set: el. panel, oven	about 9.5KW	Calculated for the power consumption of the kit	6mm² (PVS 3*3-4) (32-42)	4mm² (PVS 5*2.5-3) (25)*3	separate at least 25A (only 380V)
Email panel (independent)	7-8 kW (7)	Calculated for panel power consumption	up to 8 kW/3.5-4mm² (PVS 3*3-4)	up to 15 kW/ 4mm² (PVS 5*2-2.5)	separate at least 25A
Email oven (independent)	about 2-3 kW	Euro socket	2-2.5mm²		not less than 16A
Gas panel		Euro socket	0.75-1.5mm²		16A
Gas oven		Euro socket	0.75-1.5mm²		16A
Washing machine	2.5-7(with drying) kW	Euro socket	1.5-2.5mm²(3-4mm²)		separate at least 16A-(32)
Dishwasher	2 kW	Euro socket	1.5-2.5mm²		separate at least 10-16A
Refrigerator, wine cabinet	less than 1KW	Euro socket	1.5mm²		16A
Hood	less than 1KW	Euro socket	0.75-1.5mm²		6-16A
Coffee machine, steamer	up to 2 kW	Euro socket	1.5-2.5mm²		16A

When choosing a wire, first of all you should pay attention to the rated voltage, which should not be less than that in the network. Secondly, you should pay attention to the material of the cores. Copper wire has greater flexibility than aluminum wire and can be soldered. Aluminum wires must not be laid over combustible materials.

You should also pay attention to the cross-section of the conductors, which must correspond to the load in amperes. You can determine the current strength in amperes by dividing the power (in watts) of all connected devices by the voltage in the network. For example, the power of all devices is 4.5 kW, voltage 220 V, which is 24.5 amperes. Use the table to find the required cable cross-section. This will be a copper wire with a cross-section of 2 mm 2 or an aluminum wire with a cross-section of 3 mm 2. When choosing a wire of the cross-section you need, consider whether it will be easy to connect to electrical devices. The wire insulation must correspond to the installation conditions.

Laid open
S	Copper conductors			Aluminum conductors
mm 2	Current	Power, kWt		Current	Power, kWt
	A	220 V	380 V	A	220 V	380 V
0,5	11	2,4
0,75	15	3,3
1	17	3,7	6,4
1,5	23	5	8,7
2	26	5,7	9,8	21	4,6	7,9
2,5	30	6,6	11	24	5,2	9,1
4	41	9	15	32	7	12
6	50	11	19	39	8,5	14
10	80	17	30	60	13	22
16	100	22	38	75	16	28
25	140	30	53	105	23	39
35	170	37	64	130	28	49

Installed in a pipe
S	Copper conductors			Aluminum conductors
mm 2	Current	Power, kWt		Current	Power, kWt
	A	220 V	380 V	A	220 V	380 V
0,5
0,75
1	14	3	5,3
1,5	15	3,3	5,7
2	19	4,1	7,2	14	3	5,3
2,5	21	4,6	7,9	16	3,5	6
4	27	5,9	10	21	4,6	7,9
6	34	7,4	12	26	5,7	9,8
10	50	11	19	38	8,3	14
16	80	17	30	55	12	20
25	100	22	38	65	14	24
35	135	29	51	75	16	28

Wire markings.

The 1st letter characterizes the material of the conductor:
aluminum - A, copper - the letter is omitted.

The 2nd letter means:
P - wire.

The 3rd letter indicates the insulation material:
B - shell made of polyvinyl chloride plastic,
P - polyethylene shell,
R - rubber shell,
N—nairite shell.
Marks of wires and cords may also contain letters characterizing other structural elements:
O - braid,
T - for installation in pipes,
P - flat,
F-t metal folded shell,
G - increased flexibility,
And - increased protective properties,
P - braid made of cotton yarn, impregnated with an anti-rot compound, etc.
For example: PV - copper wire with polyvinyl chloride insulation.

Installation wires PV-1, PV-3, PV-4 are intended for supplying power to electrical devices and equipment, as well as for stationary installation of lighting electrical networks. PV-1 is produced with a single-wire conductive copper conductor, PV-3, PV-4 - with twisted conductors of copper wire. The wire cross-section is 0.5-10 mm 2. The wires have painted PVC insulation. They are used in alternating current circuits with a rated voltage of no more than 450 V with a frequency of 400 Hz and in direct current circuits with voltages up to 1000 V. The operating temperature is limited to the range -50…+70 °C.

The PVS installation wire is intended for connecting electrical appliances and equipment. The number of cores can be 2, 3, 4 or 5. The conductive core made of soft copper wire has a cross-section of 0.75-2.5 mm 2. Available with twisted conductors in PVC insulation and the same sheath.

It is used in electrical networks with a rated voltage not exceeding 380 V. The wire is designed for a maximum voltage of 4000 V, with a frequency of 50 Hz, applied for 1 minute. Operating temperature - in the range -40...+70 °C.

The PUNP installation wire is intended for laying stationary lighting networks. The number of cores can be 2.3 or 4. The cores have a cross-section of 1.0-6.0 mm 2. The conductor is made of soft copper wire and has plastic insulation in a PVC sheath. It is used in electrical networks with a rated voltage of no more than 250 V with a frequency of 50 Hz. The wire is rated for a maximum voltage of 1500 V at a frequency of 50 Hz for 1 minute.

Power cables of the VVG and VVGng brands are designed for transmitting electrical energy in stationary alternating current installations. The cores are made of soft copper wire. The number of cores can be 1-4. Cross-section of current-carrying conductors: 1.5-35.0 mm 2. The cables are produced with an insulating sheath made of polyvinyl chloride (PVC) plastic. VVGng cables have reduced flammability. Used with a rated voltage of no more than 660 V and a frequency of 50 Hz.

NYM brand power cable is designed for industrial and domestic stationary installation indoors and outdoors. The cable wires have a single-wire copper core with a cross-section of 1.5-4.0 mm 2, insulated with PVC plastic. The outer shell, which does not support combustion, is also made of light gray PVC plastic.

This seems to be the main thing that it is advisable to understand when choosing equipment and wires for them))

Conductor cross-section for power and current for electrical wiring in an apartment

Electrical installation work is a complex and responsible undertaking. If your qualifications are sufficient to do the electrical wiring in the apartment with your own hands, useful tips will come in handy. If not, then use the services of electrical installation specialists. So, let's talk about choosing the wire cross-section for current and power in detail.

Calculation of the length and maximum load of electrical wiring

Correct calculation of the wire cross-section for power and current is an important condition for the uninterrupted and trouble-free operation of the electrical system. First, calculate the total wiring length. The first way is to measure the distances between panels, switches and sockets on the wiring diagram, multiplying the number by the scale. The second way is to determine the length according to the location where the electrical wiring is designed. It includes all wires, installation and installation cables along with fastenings, support and protective structures. Each segment must be extended by at least 1 cm, taking into account the wire connections.

Next, the total load of consumed electricity is calculated. This is the sum of the rated powers of all electrical appliances that will operate in the house (*see table at the end of the article). For example, if in the kitchen an electric kettle, electric stove, microwave, lamps, and dishwasher are turned on at the same time, we sum up the power of all appliances and multiply by 0.75 (simultaneity coefficient). The load calculation must always have a margin of reliability and strength. We remember this figure to determine the cross-section of the wire cores.

A simple formula will help you determine the current consumption of any electrical appliance yourself. Divide the power consumption (see the instructions for the device) by the network voltage (220 V). For example, according to the passport, the power of the washing machine is 2000 W; 2000/220 = maximum current during operation will not exceed 9.1A.

Another option is to use the recommendations of the PUE (Electrical Installation Rules), according to which standard apartment wiring with a continuous load of 25A is calculated for the maximum current consumption and is carried out with copper wire with a cross-section of 5mm 2. According to the PUE, the cross-section of the core must be at least 2.5 mm 2, which corresponds to a conductor diameter of 1.8 mm.

This current is set to circuit breaker at the entrance of wires into the apartment to prevent accidents. In residential buildings, single-phase current with a voltage of 220 V is used. We divide the calculated total load by the voltage value (220 V) and obtain the current that will pass through the input cable and the machine. You need to buy a machine with exact or similar parameters, with a margin of current load.

Choosing a cable for electrical wiring in an apartment

* Table of power consumption and current
household electrical appliances with a supply voltage of 220V

Household electrical appliance	Power consumption depending on the model of the electrical appliance, kW (BA)	Current consumption, A	Note
Incandescent lamp
Electric kettle			Continuous operation time up to 5 minutes
Electric stove			For power greater than 2 kV, separate wiring is required
Microwave
Electric meat grinder
Coffee grinder			During operation, the current consumption varies depending on the load.
Coffee maker
Electric oven			During operation, the maximum current is consumed periodically
Dishwasher
Washing machine			Maximum current consumed from the moment of switching on until the water is heated
			During operation, the maximum current is consumed periodically
			During operation, the current consumption varies depending on the load.
Desktop computer			During operation, the maximum current is consumed periodically
Power tools (drill, jigsaw, etc.)			During operation, the current consumption varies depending on the load.

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 accordingly 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 non-armored
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.

The quality of electrical installation work affects the safety of the entire building. The determining factor when carrying out such work is the cable cross-section. To carry out the calculation, you need to find out the characteristics of all connected electricity consumers. It is necessary to calculate the cable cross-section based on power. The table is needed to see the required indicators.

A high-quality and suitable cable ensures safe and durable operation of any network

The optimal cross-sectional area of ​​the cable allows the maximum amount of current to flow without heating up. When carrying out an electrical wiring project, it is important to find the correct value for the wire diameter that would suit the specific power consumption conditions. To perform the calculations, you need to determine the total current. In this case, you need to find out the power of all equipment that is connected to the cable.

Before work, the wire cross-section and load are calculated. The table will help you find these values. For a standard 220 volt network, the approximate current value is calculated as follows: I(current)=(P1+P2+….+Pn)/220, Pn – power. For example, the optimal current for an aluminum wire is 8 A/mm, and for a copper wire is 10 A/mm.

The table shows how to carry out calculations, knowing the technical characteristics

Load calculation

Even having determined the desired value, you can make certain adjustments for the load. After all, it’s not often that all devices work simultaneously on the network. To make the data more accurate, it is necessary to multiply the cross-sectional value by Kc (correction factor). If all equipment is turned on at the same time, then this coefficient does not apply.

To perform calculations correctly, use the table for calculating cable cross-section by power. It should be taken into account that there are two types of this parameter: reactive and active.

An alternating current flows in electrical networks, the indicator of which can change. Active power is needed to calculate the average. Electric heaters and incandescent lamps have active power. If there are electric motors and transformers in the network, then some deviations may occur. At the same time, reactive power is generated. In calculations, the reactive load indicator is reflected as a coefficient (cosph).

Helpful information! In everyday life, the average cosph value is 0.8. But for a computer this figure is 0.6-0.7.

Calculation by length

Calculations of parameters along the length are necessary when constructing production lines, when the cable is subjected to heavy loads. For calculations, use a table of cable cross-sections for power and current. When current moves along highways, power losses appear, which depend on the resistance appearing in the circuit.

According to technical parameters, the largest voltage drop should not be more than five percent.

Using a table of wire cross-sections by power

In practice, a table is used to carry out calculations. Calculation of the cable cross-section for power is carried out taking into account the shown dependence of the current and power parameters on the cross-section. There are special standards for the construction of electrical installations, where you can view information on the required measurements. The table shows common values.

To select a cable for a certain load, you need to make some calculations:

• calculate the current strength indicator;
• round to the highest using the table;
• select the closest standard parameter.

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Important information! Most manufacturers reduce the section size to save material. Therefore, when making a purchase, use a caliper and measure the wire yourself, and then calculate the area. This will avoid problems with overload. If the wire consists of several twisted elements, then you need to measure the cross-section of one element and multiply by their number.

What are some examples?

A specific diagram will allow you to make the right choice of cable cross-section for your apartment. First of all, plan the places where the light sources and sockets will be placed. You should also find out which equipment will be connected to each group. This will allow you to draw up a plan for connecting all elements, as well as calculate the length of the wiring. Don't forget to add 2 cm at the joints of the wires.

Determination of wire cross-section taking into account different types of load

Using the obtained values, the current value is calculated using formulas and the cross section is determined from the table. For example, you need to find out the wire cross-section for a household appliance whose power is 2400 W. We calculate: I = 2400/220 = 10.91 A. After rounding, 11 A remains.

To determine the exact cross-sectional area, different coefficients are used. These values ​​are especially relevant for a 380 V network. To increase the safety margin, it is worth adding another 5 A to the obtained indicator.

It is worth considering that three-core wires are used for apartments. Using the tables, you can select the closest current value and the corresponding wire cross-section. You can see what wire cross-section is needed for 3 kW, as well as for other values.

Wires of different types have their own calculation subtleties. Three-phase current is used where equipment of significant power is needed. For example, this is used for production purposes.

To identify the necessary parameters in production, it is important to accurately calculate all coefficients, as well as take into account power losses due to voltage fluctuations. When performing electrical work at home, you do not need to carry out complex calculations.

You should be aware of the differences between aluminum and copper wire. The copper version has a higher price, but at the same time surpasses its analogue in technical characteristics. Aluminum products can crumble on bends, and also oxidize and have a lower thermal conductivity. For safety reasons, only copper products are used in residential buildings.

Basic cable materials

Since alternating current moves through three channels, a three-core cable is used for installation work. When installing acoustic devices, cables with a minimum resistance value are used. This will help improve signal quality and eliminate possible interference. To connect such structures, wires are used, the size of which is 2 * 15 or 2 * 25.

Some average values ​​will help you choose the optimal cross-sectional indicator for everyday use. For sockets it is worth purchasing a 2.5 mm2 cable, and for lighting design - 1.5 mm2. Equipment with higher power requires a cross-section size of 4-6 mm2.

A special table will help if you have any doubts during the calculations. To determine accurate indicators, you need to take into account all the factors that influence the current in the circuit. These are the length of individual sections, installation method, type of insulation and permissible overheating value. All data helps to increase productivity on a production scale and use electrical energy more efficiently.

Calculation of cable and wire cross-section by power and current for connecting a private house (video)

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