The quality of work of electrical system of any building depends on the choice of cable. And on the seasonal dacha where there are differences of tension and other troubles, the integrity of buildings and safety of people which are in rooms depends on correctness of its choice.
It is required to you
- - aluminum and copper cable;
- - documents on the household equipment;
- - caliper or micrometer.
Instruction
1. Pay attention of what metal the cable is made. As a rule, it can be aluminum or copper. Aluminum cables are oxidized stronger, less flexible, carry electric current, at the same section worse, as copper. But they are easier and cheaper.
2. Calculate the cable section necessary for normal operation of all equipment on the site. The main types of its sections offered by the industry – 0.75; 1; 1.5; 2.5; 4; 6; 10 mm². It is important to pick up correctly them in order that the wire did not overheat and did not threaten with the fire.
3. As a rule, cables consist of several veins. Their quantity fluctuates from 2 to 4. Section if it is not specified, learn, having measured dimeter of his veins which are cleaned from isolation by means of caliper or micrometer. In this case section will be equal 0.25 ∙π ∙ to d² where π=3.14, and d – vein dimeter in millimeters. Increase result by the number of veins and receive section in mm².
4. Make the choice of section, having calculated current which has to feed consumers. At the same time consider that for aluminum cable on each mm² of section the current 5 A is allowed, and for copper wire this size is 8 A. After that calculate the total power of all consumers to whom current is brought. Divide this power into line voltage and receive value of the electric current passing on cable.
5. For example, if it is necessary to power the 6 kW boiler, illumination of 2 kW, and other 4 kW consumers, knowing that standard line voltage is equal to 220 V. Naydita maximum current which is necessary for operation of all equipment. For this purpose find the sum of capacities which is 12 kW. Having transferred to watts receive 12000 W. Then divide power into tension 12000/220=54.55 A. Make calculation of section: for the copper cable it will be 54.55/8≈7 mm². Pick up the closest standard value of section which is more than 7 mm². For aluminum cable this value will be 54,55/5≈11 mm². Pick up it from standard options which section more than 11 mm².