2023 Author: Philip Bishop  [email protected]. Last modified: 20230524 22:24
 How to use an online calculator?
 Calculation of power loss in the cable according to the school formula
 Why do you need to calculate the voltage loss in the cable?
 Ways to reduce power loss in the cable
 Table for calculating the wire crosssection by power
 Video on the correct choice of wire crosssection and typical mistakes
How to correctly and accurately calculate the cable crosssection for voltage loss? Very often, when designing power supply networks, a competent calculation of cable losses is required. The exact result is important for the selection of material with the required conductor crosssectional area. If the cable is chosen incorrectly, this will entail multiple material costs, because the system will quickly fail and stop functioning. Thanks to the helpers' sites, where there is a readymade program for calculating the cable crosssection and losses on it, this can be done easily and quickly.
How to use an online calculator?
In the finished table, you need to enter data according to the selected cable material, system load power, network voltage, cable temperature and the method of its laying. Then press the "calculate" button and get the finished result.
Such a calculation of voltage losses in the line can be safely applied in work, if you do not take into account the resistance of the cable line under certain conditions:
 The indicating power factor cos phi is equal to one.
 DC network lines.
 AC mains with a frequency of 50 Hz made with conductors with crosssections up to 25.0–95.0.
The results obtained must be used according to each individual case, taking into account all the errors of cable and wire products.
Be sure to fill in all values!
Line length (m) / Cable material:  CopperAluminum  
Load power (W) or current (A):  
Mains voltage (V): 
Power 
1st phase  
Power factor (cosφ):  Current  3 phases  
Allowable voltage loss (%):  
Cable temperature (° C):  
Cable routing method: 
Open wiring Two single cores in a pipe Three single cores in a pipe Four single cores in a pipe One two cores in a pipe One three cores in a pipe laying in boxes, 14 cables laying in boxes, 56 cables laying in boxes, 79 cables laying in boxes, 1011 cables laying in boxes, 1214 cables laying in boxes, 1518 cables 

Cable crosssection not less (mm²)  
Current density (A / mm²)  
Wire resistance (ohm)  
Load voltage (V)  
Voltage loss (V /%) 
Calculators from wpcalc.com
Calculation of power loss in the cable according to the school formula
You can get the necessary data as follows, using the following combination of indicators for calculations: ΔU = I · RL (voltage loss in the line = current consumption * cable resistance).
Why do you need to calculate the voltage loss in the cable?
Excessive energy dissipation in the cable can lead to significant energy losses, strong heating of the cable and damage to the insulation. It is dangerous for human and animal life. With a significant line length, this will affect the cost of light, which will also adversely affect the material condition of the owner of the premises.
In addition, uncontrolled voltage losses in the cable can cause failure of many electrical appliances, as well as their complete destruction. Very often, residents use less cable crosssections than necessary (in order to save money), which soon causes a short circuit. And the future costs of replacing or repairing electrical wiring do not pay off the wallets of "thrifty" users. That is why it is so important to choose the right cable crosssection of the wires to be laid. Any electrical installation in a residential building should be started only after careful calculation of cable losses. It is important to remember that electricity does not give a second chance, and therefore everything must be done initially correctly and efficiently.
Ways to reduce power loss in the cable
Losses can be reduced in several ways:
 an increase in the cable crosssectional area;
 reducing the length of the material;
 decrease in load.
It is often more difficult with the last two points, and therefore it is necessary to do this by increasing the crosssectional area of the conductor of the electric cable. This will help reduce resistance. This option has several costly issues. First, the cost of using such a material for multikilometer systems is very significant, and therefore it is necessary to choose a cable of the correct crosssection in order to reduce the power loss threshold in the cable.
Online calculation of voltage losses allows you to do this in a few seconds, taking into account all additional characteristics. For those who wish to check the result manually, there is a physical and mathematical formula for calculating the voltage loss in the cable. Of course, these are great helpers for every electric grid designer.
Table for calculating the wire crosssection by power
Cable section, mm ^{2}
Open wiring 
Channel laying 

Copper 
Aluminum 
Copper 
Aluminum 

Current 
power, kWt 
Current 
power, kWt 
Current 
power, kWt 
Current 
power, kWt 

AND  220V  380V  AND  220V  380V  AND  220V  380V  AND  220V  380V  
0.5  eleven 
2.4 
                  
0.75  fifteen  3.3                    
1.0  17  3.7  6.4      fourteen  3.0  5.3        
1.5  23  5.0  8.7      fifteen  3.3  5.7     
 

2.0  26  5.7  9.8  21  4.6  7.9  nineteen  4.1  7.2  14.0  3.0  5.3 
2.5  thirty  6.6  11.0  24  5.2  9.1  21  4.6  7.9  16.0  3.5  6.0 
4.0  41  9.0  15.0  32  7.0  12.0  27  5.9  10.0  21.0  4.6  7.9 
6.0  50  11.0  19.0 
39 
8.5  14.0  34  7.4  12.0  26.0  5.7  9.8 
10.0  80  17.0  30.0  60  13.0  22.0  50  11.0  19.0  38.0  8.3  14.0 
16.0  100  22.0  38.0  75  16.0  28.0  80  17.0  30.0  55.0  12.0  20.0 
25.0  140  30.0  53.0  105  23.0  39.0  100  22.0 
38.0 
65.0  14.0  24.0 
35.0  170  37.0  64.0  130  28.0  49.0  135  29.0  51.0  75.0  16.0  28.0 