How to choose an electric cable
The choice of cables depends on the quality of the electrical system of any building. But at their summer cottage, where there are voltage fluctuations and other troubles, on the correctness of his choice depends on the integrity of the buildings and the safety of people who are on the premises.
You will need:
- aluminum and copper cable; - Documents for household equipment; - Vernier calipers or a micrometer.
Instruction how to choose an electric cable
Note is made of a metal cable. As a rule, it can be aluminum or copper. Aluminium cables more oxidized and less flexible, less-conductive, with the same section as the copper. But they are easier and cheaper.
Calculate the cable cross-section required for the normal operation of all the equipment at the site. The main types of its sections, the commercially - 0.75; 1; 15; 2.5; 4; 6; 10 mm². It is important to pick them to lead is not overheated and not threatened by fire.
Typically, cables consist of several strands. Their number varies from 2 to 4. The cross-section if it is not specified, find out by measuring with calipers or a micrometer dimeter his veins, who cleared off the insulation. In this case, the cross section will be equal to 0,25 ∙ π ∙ d², where π = 3,14, and d - Diameter of wires in millimeters. Multiply the result by the number of cores and mm² per conductor get.
Selecting the section make, calculating the current which must nourish consumers. At the same time, keep in mind that is 8 A. After that calculates the total power of the consumers, which is fed to the current aluminum cables for each mm² cross-section allowed current 5 A, and for copper wire, this value. Divide the power on the mains voltage value, and receive the electric current passing through the cable.
For example, if you want to power the boiler capacity of 6 kW, 2 kW lighting, and other consumers of 4 kW, knowing that the standard voltage is equal to 220 V. Find the maximum current that is needed to run all the equipment. To get this amount of power, which is 12 kW. Translating get 12,000 watts watts. Then divide by the power voltage of 12000/220 = 54.55 A. Make a cross-section calculation: for copper cable, it will be 54,55 / 8≈7 mm². Pick the nearest standard value of the cross section, which is more than 7 mm². For aluminum cable, this value will be 54,55 / 5≈11 mm². Pick it from the standard options, cross-section greater than 11 mm².