Antipyretics for children are prescribed by a pediatrician. But there are situations of emergency care for fever, when the child needs to give the medicine immediately. Then the parents take responsibility and apply antipyretic drugs. What is allowed to give to infants? How can you bring down the temperature in older children? Which medications are the safest?
This article will tell you how to calculate the section of the wire by the power consumption independently. You need to know this not only when installing electrical wiring in the house, but also when carrying out work in cars, for example. If it proves to be inadequate, it will begin to heat very much, which will lead to a significant loss of safety. Considering all the recommendations that will be set out below, you will be able to independently calculate the parameters of the wires for the installation of electricity in the house. But if you are not confident in your abilities, it is better to consult specialists in this field. And it should be noted that the calculation of the wire cross section for the power consumption (12V and 220V) is made similarly.
Carrying out of calculation of length of electroconducting
For any type of electronic system, the most important condition for stable and trouble-free operation is the correct calculation of the cross sections of all wires for current and power. The first step is to calculate the maximum length of the entire wiring. There are several ways to do this:
- Measuring the distance from the flaps to the sockets, switches according to the wiring diagram. And you can do it with a ruler on a pre-prepared plan for wiring - you can multiply the obtained length values by the scale.
- And the second, more accurate way is to arm yourself with a ruler and walk through all the rooms, taking measurements. And you need to take into account that the wires must somehow connect, so there should always be a supply - at least one or two centimeters from each edge of the wiring.
Now you can proceed to the next step.
Calculation of the load on the wiring
To calculate the total load, you need to add all the minimum power of consumers in the house. Let's say you spend the calculation for the kitchen, it has fixtures, a microwave oven, an electric kettle and a stove, a dishwasher and so on. All the power must be summed up (see the rear covers, but you'll have to calculate the current by yourself for this parameter). After multiplying by a correction factor of 0.75. It is also called the simultaneity coefficient. Its essence is clear from the name itself. This figure, which will be obtained as a result of the calculations, will be necessary for you in future to carry out calculations of the parameters of the wires. Please note that everything must be safe, reliable and durable. These are the main requirements that must be taken into account when calculating the cross-section of the wire according to the power consumption of 12V and 220V.
Current consumption of electrical installations
Now on how to calculate the current consumption electrical appliance. You can do this in your mind, but you can do it on a calculator. See the instructions to the device, what is the value of the power consumption in it. Of course, AC power is running in the household electricity supply with a voltage of 220 volts. Therefore, using a simple formula (the power consumed divided by the supply voltage), you can calculate the current. For example, an electric kettle has a power of 1000 watts. So, if we divide 1000 by 220, we get a value of about 4.55 amperes. It is very simple to calculate the cross-section of the wire according to the power consumption. How to implement this, is told in the article. In operating mode, the kettle consumes 4.55 amperes from the network (for protection, it is necessary to set a higher value). But notice that this is not always the exact meaning. For example, if there is an engine in the design of the appliance, it is possible to increase by approximately 25% the value obtained - the current consumption of the motor in the start-up mode is much larger than during idling.
But you can use a set of rules and standards. There is such a document as it regulates all the norms of wiring installation not only in private domains, but also in factories, factories, etc. According to these rules, the electrical wiring standard is the ability to withstand a load of 25 amperes for a long time. Therefore, in apartments all wiring should be carried out only using copper wire, its cross section - not less than 5 square meters. mm. Each vein should have a cross section of more than 2.5 square meters. mm. The conductor diameter should be 1.8 mm.
To ensure that all wiring works as safely as possible, an automatic circuit breaker is installed at the input. He will protect the apartment from short circuits. Also recently, most owners of living spaces are installing protective circuit breakers, which immediately act to change the resistance in the circuit. In other words, if you accidentally touch under tension, they will instantly de-energize and you will not get hit. Circuit breakers must be calculated according to the current, and it is necessary to choose with a reserve, so that it is always possible to install an electrical appliance in the house. A competent calculation of the cross-section of the wire according to the power consumption (how to make the right choice of wires, you will learn from this material) is a guarantee that the electricity supply will function correctly and efficiently.
Materials for the manufacture of wires
Typically, the installation or apartment is done using three-wire wires. And each vein - a separate insulation, they all have different colors - brown, blue, yellow-green (standard). The vein is that part of the wire through which the current flows. It can be either single-wire or multiwire. In some brands of wire, a cotton braid over the veins is used. Materials for wire cores:
- Steel.
- Copper.
- Aluminum.
Sometimes you can find a combination, for example, a copper wire stranded with several steel conductors. But they were used for field telephone communication - a signal was transmitted over the copper, and steel was used for the most part to mount the supports. Therefore, in this article about such wires the conversation will not go. For apartments and private houses, the copper wire is ideal. It is durable, reliable, the characteristics are much higher than that of cheap aluminum. Of course, the price of a copper wire bites, but worth mentioning is that its service life (guaranteed) is 50 years.
Wire grades
For the installation of electrical wiring is best to use two brands of wires - VVGng and VVG. The first has the ending "-ng", which indicates that the insulation is not lit. It is used to conduct electrical wiring inside buildings and buildings, as well as in the ground, in the open air. Stable operation in the temperature range -50 ... +50. Guaranteed service life - not less than 30 years. The cable can be with two, three or four wires, the cross section of each - in the range of 1.5 ... 35 square meters. mm. Pay attention also to the fact that it is necessary to calculate the cross-section of the wire according to the power consumption and length (in the case of an air long line).
Carefully look at the fact that before the name of the wire there was no letter "A" (for example, AVVG). This indicates that the veins are made of aluminum inside. There are also foreign analogues - NYM cable, which has a round shape, meets the standards adopted in Germany (VDE0250). The conductors are copper, insulation is not subject to combustion. The round form of the wire is much more convenient if it is necessary to conduct the installation through the wall. But to conduct wiring inside the premises is more convenient flat domestic.
Wires made of aluminum
They have a small weight, and most importantly, low cost. Therefore, useful for those cases where you need to lay long lines through the air. If all work is done correctly and correctly, you will get an ideal air line, since aluminum has one huge advantage - it is not subject to oxidation (unlike copper). But often the wiring from aluminum was used in homes (usually in old ones). Earlier it was easier to get a wire, and it cost a penny. It should be noted that the calculation of the cross-section of the wire according to the power consumption (the features of this process are known to every electrician) is the main stage in the construction of the project of electricity supply to the house. But you need to pay attention to one feature - the cross-section of aluminum wire should be more than copper to withstand the same load.
Table for calculating the cross section for power
Also it is necessary to mention that on aluminum wires the maximum permissible current load is much less than for copper wires. The table below will help you calculate the cross-section of the conductors of the aluminum wiring.
Cross-section of wires depending on the type of wiring
There are two types of installation electrical wiring in homes - open and closed. As you understand, this nuance must be taken into account when making calculations. Hidden is installed inside the floors, as well as in grooves and channels, in pipes, etc. Closed wiring has higher requirements, since it has less ability to cool. And any wire with prolonged exposure to a large load heats up very much. Therefore, in case when you are calculating the cross-section of the wire according to the power consumption, the influence on heating must be taken into account. It is also necessary to take into account the following parameters:
- Continuous current load.
- Loss of tension.
As the length of the wire increases, the voltage decreases. Therefore, in order to reduce the voltage loss, it is necessary to increase the cross-section of the wires of the wire. When it comes to small house or even a room, the value of losses is extremely low, they can be neglected. But if you are calculating a long line, this does not go away. After all, the calculation of the cross-section of the wire according to the power consumption (the influence of length is very large) depends on such a parameter as the length of the line.
Power Wire Calculation
So, you need to know the following characteristics:
- The material of which the cores of the cable consist.
- The maximum power consumption.
- Supply voltage.
Pay attention to the fact that when any current flows there is an increase in temperature and the release of a certain amount of heat. And the amount of heat is proportional to all the power that is dissipated on the piece of electrical wiring. If you choose the wrong cross-section, then excessive heating will occur, and the result may be deplorable - ignition of electrical wiring and fire. Therefore, it is worthwhile to make an accurate calculation of the wire cross section for the power consumption. Risk factors are too large, and there are many.
Optimal parameters
Optimal sections:
- For routing outlets - 2.5 square meters. mm.
- Lighting group - 1.5 square meters. mm.
- Electrical appliances of high power (electric stove) - 4-6 square meters. mm.
In this case, pay attention to the fact that copper wires can withstand the following loads:
- The wire is 1.5 square meters. mm - up to 4,1 kW (load current - 19 amperes).
- 2.5 sq. M. mm - up to 5.9 kW (current - up to 27 amperes).
- 4-6 square meters. mm - more than 8-10 kW.
Therefore, when you increase the load, you will always have a fairly large reserve.
Conclusion
Now you know how to calculate the cross-section of the wire by the power consumption (the definition of important characteristics and other small factors is now known to you). Based on all the above data, you will be able to independently, without recourse to the help of professionals, draw up a properly planned electricity plan for your house or apartment.
At the device of electroconducting it is necessary to define in advance power of consumers. This will help in optimal choice cables. This choice will allow long and safe operation of the wiring without repair.
Cable and conductor products are very diverse in their properties and purpose, and also have a wide spread in prices. The article tells about the most important parameter of the wiring - the cross-section of the wire or cable by current and power, and how to determine the diameter - calculate by the formula or select using the table.
The current-carrying part of the cable is made of metal. A part of the plane passing at right angles to the wire bounded by a metal is called wire cross section. The unit of measurement is a square millimeter.
Section determines allowable currents, passing in the wire and cable. This current, according to the Joule-Lenz law, leads to the release of heat (proportional to the resistance and square of the current), which limits the current.
Conditionally, there are three temperature ranges:
- isolation remains intact;
- the insulation burns, but the metal remains intact;
- metal melts from heat.
Of these, only the first is the permissible operating temperature. In addition, as the cross section decreases increases its electrical resistance, which leads to an increase in the voltage drop in the wires.
However, increasing the cross section leads to an increase in mass and especially cost or cable.
From materials for the industrial production of cable products use a clean copper or aluminum. These metals have different physical properties, in particular, the resistivity, and therefore the cross sections chosen for a given current can be different.
Learn from this video how to properly choose the wire or cable cross-section for power for home wiring:
Determination and calculation of cores by the formula
Now let's figure out how to calculate the cross-section of a wire in terms of power knowing the formula. Here we solve the problem of determining the cross section. It is the cross-section that is the standard parameter, because the nomenclature includes both single-core version, and stranded. Advantage multicore cables in their greater flexibility and resistance to kinks during installation. As a rule, strands are made of copper.
The simplest way to determine the cross section of a round solid wire, d - diameter, mm; S - area in square millimeters:
Stranded are calculated by a more general formula: n - number of cores, d - diameter of the core, S - area:
The diameter of the core can be determined by removing the insulation and measuring the diameter of the bare metal with a caliper or micrometer.
The current density is determined very simply, this number of amps per section. There are two options for posting: open and closed. Open allows a higher current density, due to better heat transfer to the environment. Closed requires corrections in the smaller side so that the heat balance does not lead to overheating in the tray, cable duct or shaft, which can cause a short circuit or even a fire.
Accurate thermal calculations are very complex, in practice they proceed from the permissible operating temperature of the most critical element in the design, which is used to select the current density.
Thus, the permissible current density is the value at which the insulation heating of all wires in the bundle (cable duct) remains safe, taking into account the maximum ambient temperature.
Table of a section of copper and aluminum wire or cable by current:
Table 1 shows the allowable current density for temperatures not above room temperature. Most modern wires have PVC or polyethylene insulation, allowable heating in operation no more than 70-90 ° C. For "hot" rooms, the current density must be reduced by a factor of 0.9 for every 10 ° C to the temperatures of the terminal operation of wires or cables.
Now about what to consider open and what. is the wiring if it is made with clamps (shink) on the walls, ceiling, along the carrier cable or through the air. The closed one is laid in cable trays, walled up under plaster, made in pipes, shell or laid in the ground. Also, the wiring should be considered closed if it is in or. Closed cooling is worse.
For example, let the thermometer in the dryer room show 50 ° C. To what value should the current density be reduced copper cable, laid in this room on the ceiling, if the cable insulation can withstand heating up to 90 ° C? The difference is 50-20 = 30 degrees, then, you need to use the coefficient three times. Answer:
Example of counting the wiring and load area
Let the false ceiling be illuminated by six lamps with a power of 80 W each and they are already connected to each other. We need to bring food to them, using aluminum cable. We will consider the wiring closed, the room dry, and the room temperature. Now we learn how to calculate the power of copper and aluminum cables, for this we use the equation that determines the power (the mains voltage according to the new standards is considered equal to 230 V):
Using the appropriate current density for aluminum from Table 1, we find the cross section necessary for the operation of the line without overheating:
If we need to find the wire diameter, use the formula:
It will be suitable cable APPV2x1.5 (section 1.5 mm.kv). This is perhaps the thinnest cable that can be found on the market (and one of the cheapest). In this case, it provides a two-fold power reserve, i.e. a consumer can be installed on this line with an acceptable load power of up to 500 W, for example, a fan, a dryer, or additional lights.
Sockets on this line should not be installed, since a powerful consumer may be included in them (and, most likely, will), and this will lead to an overload of the section of the line.
Quick Selection: Useful Standards and Ratio
To save time, calculations are usually reduced to tables, especially since the range of cable products is rather limited. The following table shows the calculation of the cross section for copper and aluminum wires according to the power consumption and current intensity, depending on the intended use - for open and closed wiring. The diameter is obtained as a function of the load power, the metal and the type of wiring. The mains voltage is 230V.
The table allows you to quickly select the cross-section or diameter, if the load power is known. The value found is rounded up to the nearest value from the nomenclature.
The following table summarizes the permissible current cross-sections and the power of cable and wire materials to calculate and quickly select the most suitable:
The wiring device, among other things, requires design skills, that is not everyone who wants to do it. It is not enough to have only good skills in wiring. Some confuse design with the design of documentation by some rules. These are completely different things. A good project can be described on the pages of the notebook.
First of all, draw a plan of your premises and note the future sockets and lamps. Find out the power of all your consumers: irons, lamps, heating appliances, etc. Then enter the power loads most often consumed in different rooms. This will allow you to choose the most optimal cable selection options.
You will be surprised how many opportunities and what is the reserve for saving money. After selecting, calculate the length of each line that you lead. Put it all together, and then you will get exactly what you need, and as much as you need.
Each line must be protected by its (), calculated for the current corresponding to the permissible power of the line (the sum of the powers of the consumers). Sign Automata, located in, for example: "kitchen", "living room", etc.
It is advisable to have a separate line for all lighting, then you can safely repair the outlet in the evening, not using matches. Sockets are often overloaded. Provide sockets of sufficient power - you do not know in advance what you will have to include there.
In damp areas, use cables with only double insulation! Use modern rosettes ("Euro") and with grounding conductors and correctly connect the ground. Solid wires, especially copper, bend smoothly, leaving a radius of several centimeters. This will prevent them from breaking. In the cable trays and channels, the wires must lie straight, but freely, in no case should they be pulled like a string.
In and there should be a margin of a few extra centimeters. When laying, you need to make sure that nowhere are sharp corners that can cut the insulation. Tighten the terminals when connecting is necessary tightly, and for stranded wires This procedure should be repeated, they have a peculiarity of shrinkage of the veins, as a result of which the connection may weaken.
Copper wires and aluminum "do not make friends" with each other for electrochemical reasons, they can not be directly connected. To do this, you can use special terminals or galvanized washers. The joints must always be dry.
We bring to your attention an interesting and informative video how to correctly calculate the cross section of the cable in terms of power and length:
The choice of wires across the section is the main element of the electricity supply project of any scale, from the room, to large networks. From this will depend on the current, which can be selected in the load and power. Right choice wires also provides electricity and fire safety , and provides an economical budget for your project.
Type of electric current
The type of current depends on the power supply system and the equipment to be connected.
Select type of current: Choose Alternating current D.C
Cable conductor material
The material of the conductors determines the technical and economic characteristics of the cable line.
Choose the material of the conductors:
Select Copper (Cu) Aluminum (Al)
Total power of the connected load
The load power for the cable is defined as the sum of the power consumption of all electrical appliances connected to this cable.
Enter the load power: kW
Rated voltage
Enter the voltage: AT
AC only
Power Supply System: Choose Single Phase Three Phase
Power factor cosφ determines the ratio of the active energy to the total. For powerful consumers, the value is indicated in the device's passport. For residential consumerscosφ is assumed to be 1.
Power factor cosφ:
Method of laying the cable
The laying method determines the heat sink conditions and affects the maximum permissible cable load.
Choose the laying method:
Select Open Postings Hidden Posting
Number of loaded wires in the beam
For direct current all wires are considered loaded, for a single-phase variable - phase and zero, for alternating three-phase - only phase.
The calculated value is the minimum allowable value of the actual cable cross-section. A significant part of the cable products sold in stores does not correspond to the marking and has an understated conductor cross-section. Check the actual cross-section of the cable conductors before use!
The calculated cable cross-section value is indicative and can not be used in power supply system projects without professional assessment and justification in accordance with regulatory documents!
Cable products are now on the market in a wide range, the cross-section of the cores is from 0.35 mm.kv. and above, this article will give an example cable cross-section calculation.
To calculate the resistance of the conductor, you can use calculator for calculating the resistance of a conductor.
Wrong cable section selection for household wiring, can lead to such results:
1. The perimeter meter of excessively thick core will cost more, which will cause a significant "blow" on the budget.
2. The cores will soon begin to heat up and will melt the insulation if an inappropriate diameter of the conductor (less than necessary) is chosen and this can soon lead to a short circuit or spontaneous combustion of the wiring.
In order not to spend money for nothing, it is necessary before starting the installation of electrical wiring in an apartment or house, to perform the correct cable cross-section calculation depending on the current strength, power and line length.
Calculation of the cable cross-section by the power of electrical appliances.
Each cable has a nominal power, which it can withstand the operation of electrical appliances. When the power of all electrical appliances in the apartment will exceed the design indicator of the conductor, the accident will soon be avoided.
Calculate the power of electrical appliances in the apartment or house you can independently, for this you need to write on a sheet of paper the characteristics of each device separately (TV, vacuum cleaner, plate, lamps). Then, all the resulting values are added together, and the final number is used to select the optimal diameter.
The formula for calculating the power is as follows:
Pobsch = (P1 + P2 + P3 + ... + Pn) * 0.8, where: P1..Pn is the power of each electrical appliance, kW
It is worth paying attention to the fact that the number that you obtained should be multiplied by a correction factor of 0.8. This factor means that only 80% of all electrical appliances will work at the same time. This calculation will be more logical, because a vacuum cleaner or a hair dryer will not be in use for a long time without interruption.
An example of calculating the power cable cross section is shown in the tables:
For a conductor with aluminum conductors.
For a conductor with copper cores.
As you can see from the tables, your data has values for each defined type of cable, it will only be necessary to find the nearest value of the power and to look at the corresponding section of the veins.
For example calculation of cable cross-section by power looks like that:
Let us assume that in the apartment the total power of all devices is 13 kW. It is necessary to multiply the obtained value by a factor of 0.8, as a result, it will give 10.4 kW of the actual load. Then the appropriate value should be found in the column of the table. The nearest figure is 10.1 for a single-phase network (220V voltage) and at three-phase network the figure is 10.5. This means that we stop the choice of the cross-section for a single-phase network on a 6-mm conductor or for a three-phase network at a 1.5-millimetric conductor.
Calculation of the cable cross-section by current load.
More accurate cable cross-section calculation, so use it best. The essence of the calculation is similar, but in this case it is necessary only to determine what the current load will be for the wiring. First, you need to calculate the current for each of the appliances using the formulas.
Average power of household electrical appliances
An example of displaying the power of an electrical appliance (in this case an LCD TV)
For the calculation it is necessary to use this formula if the apartment single-phase network:
I = P / (U × cosφ)
When the network is three-phase, the formula will look like this:
I = P / (1,73 × U × cosφ), where P is the electrical load power, W;
- U - actual voltage in the network, V;
- cosφ is the power factor.
It should be taken into account that the values of the tabulated values will depend on the conditions of the conductor laying. The power and current loads will be significantly greater when installing the open wiring than if the wiring harness is in the pipe.
The resulting total value of the currents for the stock is recommended to be multiplied by 1.5 times, because in time, more powerful electrical appliances can be purchased into the apartment.
Calculation of the cable cross-section along the length.
You can also by length, calculate the cross-section of the cable. The essence of such calculations is that each of the conductors has its own resistance, which contributes to current losses with increasing line length. It is necessary to choose a conductor with veins larger, if the loss value exceeds 5%.
Calculations occur as follows:
- The total power of all electrical appliances and the current are calculated.
- Then, the resistance of the wiring is calculated according to the formula: conductor specific conductivity (p) * length (in meters).
- It is necessary to divide the resulting value into the selected cable cross-section:
R = (p * L) / S, where p is the tabulated value
It should pay attention to the fact that the length of the current passage must be multiplied by a factor of 2, since initially the current flows along one vein, and the back passes through the other.
- The voltage loss is calculated: the current is multiplied by the calculated resistance.
- Next, the loss value is determined: the voltage losses are divided by the voltage in the network and multiplied by 100%.
- The final number is analyzed. If the value obtained is less than 5%, the selected section of the core can be left, but if more, then the conductor should be chosen to be "thicker".
Table of resistivities.
It is necessary to make a calculation taking into account the losses along the length, if the line extends a fairly long distance, otherwise there is a high probability select cable cross-section wrong.
To date, there is a wide range of cable products, with a cross-section of cores from 0,35 mm.kv. and higher.
If you incorrectly select the cable cross section for household wiring, the result can have two totals:
- Too thick a vein will "hit" on your budget, tk. its linear meter will cost more.
- If the conductor diameter is not suitable (less than necessary), the cores will begin to heat up and melt the insulation, which will soon lead to spontaneous combustion of the electrical wiring and short circuit.
As you understand, both of these results are disappointing, therefore, before the apartment, it is necessary to correctly calculate the cross-section of the cable, depending on the power, current strength and length of the line. Now we will take a closer look at each of the techniques.
Calculation of the power of electrical appliances
Each cable has a nominal power that it can withstand when running electrical appliances. If the power of all devices in the house will exceed the indicator of the conductor, then the accident can not be avoided in the near future.
To independently calculate the power of electrical appliances in the house, it is necessary to write down the characteristics of each device separately (a plate, a TV, lamps, a vacuum cleaner, etc.) on a sheet of paper. After that, all values are summed up, and the finished number is used to select the optimal diameter.
The calculation formula has the form:
Pobsch = (P1 + P2 + P3 + ... + Pn) * 0.8,
Where: P1..Pn-power of each device, kW
We draw your attention to the fact that the resulting number must be multiplied by a correction factor of 0.8. This factor means that only 80% of all electrical appliances will work simultaneously. This calculation is more logical, because, for example, you will not use the vacuum cleaner or hair dryer for a long time without interruption.
Tables for selecting the cable cross-section by power:
For conductor with aluminum conductors
For conductor with copper conductors
As you can see, for each specific type of cable, the table values have their data. All you need is to find the nearest value of power and look at the corresponding cross-section of cores.
To make you understand how to correctly calculate the cable by power, we give a simple example:
We calculated that the total capacity of all electrical appliances in the apartment is 13 kW. This value should be multiplied by a factor of 0.8, which as a result will give 10.4 kW of the actual load. Next, in the table, look for a suitable value in the column. We are satisfied with the figure "10.1" with a single-phase network (voltage 220V) and "10.5", if the network is three-phase. Total, the choice of the cross-section is stopped with a 6-mm conductor with a single-phase network or with a 1.5-millimeter meter with a three-phase network. As you can see, everything is quite simple and even an electrician-beginner to cope with such a task independently!
Calculation of the current load
Calculating the cross-section of the current cable is more accurate, so it's best to use it. The essence is similar, but only in this case it is necessary to determine the current load on the wiring. To begin with, we use the formulas to calculate the current strength for each of the devices.
If the house is a single-phase network, you need to use the following formula to calculate:For a three-phase network, the formula will look like:
Where, P - power of electrical appliance, kW
We draw your attention to the fact that the table values will depend on the conditions of the conductor's laying. With current loads and power will be much larger than at.
It should be noted that the total value of currents obtained in the calculation is recommended to be multiplied by one and a half times, for the stock. Suddenly, over time, you decide to purchase more powerful devices?
Cable selection table for current:
Calculation by length
Well, the last way to calculate the cross-section of the cable is along the length. The essence of the following calculations is that each conductor has its own resistance, which with increasing the length of the line contributes to current losses (the greater the distance, the greater the loss). In the event that the amount of losses exceeds the 5% mark, it is necessary to choose a conductor with veins larger.
For calculations, the following procedure is used:
- It is necessary to calculate the total power of electrical appliances and the current (above we provided the corresponding formulas).
- The electrical wiring resistance is calculated. The formula has the following form: conductor specific conductivity (p) * length (in meters). The resulting value must be divided into the selected cable cross-section.
R = (p * L) / S, where p is the tabulated value
We draw your attention to the fact that the length of the current passage must be multiplied by two times, because current initially goes through one vein, and then comes back on the other.
- Voltage losses are calculated: the current is multiplied by the calculated resistance.
- The amount of losses is determined: the voltage losses are divided by the voltage in the network and multiplied by 100%.
- The final number is analyzed. If the value is less than 5%, leave the selected section of the core. Otherwise, we select a more "thick" conductor.
Resistivity table:
If you are pulling the line for a fairly long distance, be sure to make a calculation taking into account the losses along the length, otherwise there will be a high probability of wrong selection of the cable section.
Video calculation examples
Visual video examples always allow you to better understand the information, so we provide them for your attention:
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