At installation of an electrical wiring sometimes there is a need to learn the section of the used wire. It is possible to find the table of diameters of wires and the sections corresponding to them in network, but the necessary value can quite be calculated independently.
It is required to you
- - caliper or micrometer;
Instruction
1. To calculate the wire section, that is its area, enough elementary knowledge from a school course of mathematics. It is known that the area of a circle is equal to the square of its radius increased by number "пи" (3.14). For example, if diameter of a wire is equal to 1 mm, then radius, respectively, will be equal to 0.5 mm. To find section, it is necessary 0.5 to square and increase by 3.14. Total, 0.5 × 0.5 × 3.14 = 0.785.
2. In practice an important point is the correct measurement of diameter of a wire. For measurement use a caliper or a micrometer. The micrometer allows to receive more exact indications. The wire is thinner, the more errors creep in calculations.
3. Correctly to determine diameter of a thin wire, use the following method: densely, a round to a round, reel up about fifty rounds of a wire on a pencil or other suitable mandrel. After that measure the general width of fifty rounds and divide the received size into 50. The more rounds, the more precisely result. In such a way it is possible to determine diameter even of very thin wires.
4. Not to spend time for calculations, you can use the table of sections of the most widespread assembly wires, the reference to it is given at the end of article. When choosing a wire for conducting surely consider the maximum current which will consume the switched-on electric equipment.
5. For calculation of current in network use formula I = P/U where P is power consumption, U is tension in network. For example, if the general loading can make 10 kW (10000 W), then conducting has to be calculated on current: 10000/220 = 46 A (you round up the received number). Further according to the table choose a copper or aluminum wire which section allows to sustain this current.
6. Considering that all electric equipment in the apartment never turns on at the same time, design load can be increased by coefficient 0.7. That is vmesto10 kW use in calculations 10 × 0.7 = 7 kW. Then conducting has to be calculated on current 7000/220 = 32 A.