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 (380V only) |
|
| 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 (380V only) |
| 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 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 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 - braided cotton yarn impregnated with an anti-rotten 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))
When designing electrical networks or similar systems, special attention is paid to the correct choice of cable, which is traditionally assessed by the standard size of the wires included in it. A competent approach to this choice requires taking into account the permissible current load in a given circuit (in other words, the power consumed or dissipated in it), which directly depends on the selected wire. To express this dependence, a classic table of currents is used, shown in the figure below. It indicates the type and cross-section of the cores of a single-core or multi-core cable and the values of the maximum current that they are capable of passing through themselves without overheating and the threat of subsequent destruction.
In this case, experts talk about what load on the cable is allowed without dangerous consequences, and the data used in this case is summarized in tables of current loads for the cross-section of copper cables. To decipher the concepts presented here, the order of their introduction and linkage to specific physical quantities will be considered below.
Basic Concepts
Wire size
The need for the correct selection of cross-section for each wire included in the electrical circuit is dictated by the following need. The fact is that a properly calculated current load across the cable cross-section allows you to operate this circuit for a long time and without any problems with full confidence that it will not fail at the most inopportune moment.
The term “wire cross-section” in electrical engineering refers to its transverse standard size, in the simplest case calculated using the classical formula (see photo below).
For simplicity, the values included in this entry are taken for a round single-core wire. They mean:
- d – diameter of one core without insulation, mm;
- S is the area measured in square millimeters.
Note! This formula is valid for the selection of single-core wires, which are used extremely rarely in real operating conditions.
In practice, as a rule, wires of n cores are used, to calculate the total cross-section of which a different formula will be required. It is shown in the figure below (the designations are the same).
Based on the data in the table of cable loads, the permissible current value in a conductor with a standard size of one square millimeter, for example, for aluminum is 4 Amperes, and for a copper wire it will be equal to 10 Amperes (when laid in a pipe).
Thus, for a current of 10 Amperes, a copper wire with a unit cross-section of 1 square meter will be required. mm (conversion factor – 10). All approximate calculations of current circuit parameters are based on this relationship. Next, we will consider another important parameter called current density (it is directly related to this topic).
Current Density
This indicator for a conductor is determined extremely simply: it is calculated as the number of amperes per unit of its cross-section. When considering the factors that influence the current density in the cable, first of all, the method of laying the wires (open and hidden) is highlighted. In the first option, a higher density index is allowed, which is explained by better conditions for heat exchange with the environment.
When laid hidden or closed, the wires laid and walled up in the grooves are practically deprived of contact with the atmosphere, and their heat transfer is reduced to a minimum. The same can be said about cables placed in special protective boxes or cable channels. When choosing the parameters of the wires laid in this case, a certain correction must be made to take into account the absence of heat dissipation into the atmosphere.
This approach to wire selection allows you to take into account the stealth factor, regardless of what load is connected to a given line or network.
Carrying out high-quality thermal calculations in domestic conditions is practically impossible, so in reality they come down to choosing the most vulnerable element of the system and calculating the total density taking into account its parameters.
For your information. The amendments made in this case are valid only if the ambient air temperature is also taken into account in its maximum value.
In all tables discussed earlier, the current and load power consumption indicators are indicated for normal room temperatures. On the other hand, most modern cable products with PVC or polyethylene insulation can be used when heated to 70-90°C.
Calculation examples
As an example, consider a specific situation for a load with a power of up to 4 kW (4000 Watt) at a network voltage of 220 Volts. In this case, the current flowing through it is 4000/220 = 18.18 Amperes, and for normal operation of the supply cable it is enough that it consists of a single-core copper wire with a cross-section of 18.18/10 = 1.818 square meters. mm (10 – conversion factor).
Important! In the example considered, the wires will be used to the limit of their capabilities, so a certain margin of cross-section of at least 15% will be required.
As a result, we get approximately 2.08 square meters, and after selecting the nearest normalized value using a special table, we take a wire of 2.0 square meters. mm.
If you want to find out how many kilowatts 2 and 5 square meters of wire cross-section can provide in a current load, you can use another summary document, called by experts “power table”. It is usually presented in a form combined with a table of currents (see figure below).
From it we find that for a section of 2.5 sq. mm, the permissible power will be equal to 4.6 kW (at a current of 21 Amperes), which is very close to the calculated data for 2.0 kW. mm.
Note! These indicators are valid only for a single copper conductor, regardless of others laid in a metal pipe.
Under other laying conditions and wire materials (aluminum, for example), the numbers will be different.
Multicore cable
For a combined cable consisting of several copper conductors laid closely together, the calculation of the maximum load (its current value) and the power in it will look different. This is due to the fact that when individual conductors are located close together, their thermal fields overlap. As a result, the maximum current and power indicators in the load have lower values (a photo of a multi-core cable is given below).
As an example, consider how much a 3x4 square cable can withstand a kilowatt. Multicore wire consisting of 3 cores with a cross section of 4 square meters. mm each, according to the tables of currents, powers and loads, is capable of withstanding a current of up to 27 Amps with a load power of up to 6 kW.
The same can be said about the cable power in kW, selected according to the same table. Products of this class, designed for high currents, are usually used to connect such energy-intensive consumers as:
- Country power equipment (pumps, electric motors, etc.);
- Washing machines and electric furnaces (ovens);
- Automatic sliding gate control systems and other mechanisms.
Multicore cable products are widely used when laying electrical wiring in apartments and private houses and are calculated using the same tables (in general, this is a load table).
Continuously permissible currents
Another factor that must be taken into account when choosing the cross-section of an electrical wire, busbar or cable installation is their heating due to the flowing current, which changes the properties of most conductive materials. Excessive heating threatens not only the gradual destruction of insulation, but also contributes to the disruption of existing contact connections, which over time can lead to irreparable consequences.
The maximum current corresponding to the maximum heating temperature of conductors or contact connections is called long-term permissible. Its value for each specific circuit is determined not only by the material of the wire, but also by its cross-section, type of insulation, and cooling conditions.
The long-term permissible heating temperature of the cores corresponding to this current lies in the range from 50 to 80 degrees Celsius (its specific value depends on the type of insulation and the applied voltage).
Additional Information. The second of these parameters can be taken from the voltage table, which, as a rule, is combined with all the previously discussed tabular data.
In the final part of the section, we note that when carrying out practical calculations of thermal conditions, you should use ready-made tables.
They usually indicate data on long-term permissible current values, determined by the heating rate of copper or aluminum conductors under various conditions of their installation (in pipes, open, in air or in the ground).
Video
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 characteristicsLoad 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 specific load, you need to make some calculations:
- calculate the current strength indicator;
- round to the highest using the table;
- select the closest standard parameter.
Related article:
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 outlets 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 installation 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-sections based on power and current for connecting a private house (video)
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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 (kBA) | 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.
Permissible long-term currents for wires with rubber or polyvinyl chloride insulation, cords with rubber insulation and cables with rubber or plastic insulation in lead, polyvinyl chloride and rubber sheaths are given in Table. 1.3.4-1.3.11. They are accepted for temperatures: cores +65, ambient air +25 and ground + 15°C.
When determining the number of wires laid in one pipe (or cores of a stranded conductor), the neutral working conductor of a four-wire three-phase current system, as well as grounding and neutral protective conductors are not taken into account.
Permissible long-term currents for wires and cables laid in boxes, as well as in trays in bundles, must be accepted: for wires - according to table. 1.3.4 and 1.3.5 as for wires laid in pipes, for cables - according to table. 1.3.6-1.3.8 as for cables laid in the air. If the number of simultaneously loaded wires is more than four, laid in pipes, boxes, and also in trays in bundles, the currents for the wires should be taken according to the table. 1.3.4 and 1.3.5 as for wires laid openly (in the air), with the introduction of reduction factors of 0.68 for 5 and 6; 0.63 for 7-9 and 0.6 for 10-12 conductors.
For secondary circuit wires, reduction factors are not introduced.
Table 1.3.4. Permissible continuous current for wires and cords with rubber and polyvinyl chloride insulation with copper conductors
|
Current, A, for wires laid in one pipe |
||||||
| 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 | - | - | - | - | - |
Table 1.3.5. Permissible continuous current for rubber and polyvinyl chloride insulated wires with aluminum conductors
| Cross-section of current-carrying conductor, mm 2 |
Current, A, for wires laid in one pipe |
|||||
| open | 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 | - | - | - | - | - |
Table 1.3.6. 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, nayrite or rubber sheaths, armored and unarmored
|
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 apply to wires and cables both with and without a neutral core. |
|||||
Table 1.3.7. Permissible continuous current for cables with aluminum conductors with rubber or plastic insulation in lead, polyvinyl chloride and rubber sheaths, armored and unarmored
| Conductor cross-section, mm2 |
Current, A, for 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 | - | - | - | - |
Note. Permissible continuous currents for four-core cables with plastic insulation for voltages up to 1 kV can be selected according to table. 1.3.7, as for three-core cables, but with a coefficient of 0.92.
Table 1.3.8. Permissible continuous current for portable light and medium hose cords, portable heavy duty hose cables, mine flexible hose cables, floodlight cables and portable wires with copper conductors
|
Conductor cross-section, mm2 |
Current *, A, for cords, wires and cables |
||
| single-core | two-wire | three-wire | |
| 0,5 | - | 12 | - |
| 0,75 | - | 16 | 14 |
| 1,0 | - | 18 | 16 |
| 1,5 | - | 23 | 20 |
| 2,5 | 40 | 33 | 28 |
| 4 | 50 | 43 | 36 |
| 6 | . 65 | 55 | 45 |
| 10 | 90 | 75 | 60 |
| 16 | 120 | 95 | 80 |
| 25 | 160 | 125 | 105 |
| 35 | 190 | 150 | 130 |
| 50 | 235 | 185 | 160 |
| 70 | 290 | 235 | 200 |
________________
* Currents refer to cords, wires and cables with and without a neutral core.
Table 1.3.9. Permissible continuous current for portable hose cables with copper conductors and rubber insulation for peat enterprises
__________________
Table 1.3.10. Permissible continuous current for hose cables with copper conductors and rubber insulation for mobile electrical receivers
__________________
* Currents refer to cables with and without a neutral core.
Table 1.3.11. Permissible continuous current for wires with copper conductors with rubber insulation for electrified transport 1.3 and 4 kV
| Conductor cross-section, mm 2 | Current, A | Conductor cross-section, mm 2 | Current, A | Conductor cross-section, mm 2 | Current, A |
| 1 | 20 | 16 | 115 | 120 | 390 |
| 1,5 | 25 | 25 | 150 | 150 | 445 |
| 2,5 | 40 | 35 | 185 | 185 | 505 |
| 4 | 50 | 50 | 230 | 240 | 590 |
| 6 | 65 | 70 | 285 | 300 | 670 |
| 10 | 90 | 95 | 340 | 350 | 745 |
Table 1.3.12. Reduction factor for wires and cables laid in boxes
| Laying method |
Number of laid wires and cables |
Reducing factor for wires supplying groups of electrical receivers and individual receivers with a utilization factor of more than 0.7 |
||
| single-core | stranded | separate electrical receivers with a utilization factor of up to 0.7 | groups of electrical receivers and individual receivers with a utilization factor of more than 0.7 | |
|
Multilayered and in bunches. . . |
- | Up to 4 | 1,0 | - |
| 2 | 5-6 | 0,85 | - | |
| 3-9 | 7-9 | 0,75 | - | |
| 10-11 | 10-11 | 0,7 | - | |
| 12-14 | 12-14 | 0,65 | - | |
| 15-18 | 15-18 | 0,6 | - | |
|
Single layer |
2-4 | 2-4 | - | 0,67 |
| 5 | 5 | - | 0,6 | |
1.3.11
Permissible long-term currents for wires laid in trays, when laid single-row (not in bundles), should be taken as for wires laid in the air.
Permissible long-term currents for wires and cables laid in boxes should be taken according to table. 1.3.4-1.3.7 as for single wires and cables laid openly (in the air), using the reduction factors indicated in table. 1.3.12.
When choosing reduction factors, control and reserve wires and cables are not taken into account.
