You will need
- micrometer, caliper or ruler, calculator.
The method of calculating the cross section of electric wire depends on the construction of this wire. To calculate the cross sections used formulas area of a circle or rectangle. The calculation is performed in the following sequence. Clean the wire of insulation to a length of about 10 mm.
To determine the cross section of the conductor is round, measure its diameter using a micrometer or caliper. If the micrometer is not turned, the diameter of the wire can be approximated using a simple ruler. To use this method, clear the wire from the insulation to the length from half a meter to one meter. Wrap 10 turns of wire on the ruler. The winding should be dense, turn to turn. Determine the length of the winding on the ruler scale and divide by ten. The resulting value is the desired diameter of wire. To improve the precision of measurement of diameter, increase the number of winding turns.
The diameter of the wireexpressed in millimeters, erected in the square. The resulting value multiply by PI and then divide by four. The result of all actions will be section of the wirein square millimeters. The value of PI to obtain a satisfactory precision is enough to take = 3.14. The number of mathematical operations can be reduced, if the advance to make the division of PI by four. In this case, the diameter squared, multiplied by 0,785.
A bit more complicated calculated cross section stranded wire. To find it, count the number of individual wires. Select the vein and measure its diameter. Calculate the cross-section of this core. The required cross-section stranded wire find by multiplying the number of cores in the cross section of one core.
If you are using wire of rectangular cross section, determine its width and height using one of the above-mentioned measuring instruments. The obtained value should have a dimension – millimeters. Multiply length by width. The result of the multiplication is the value of the cross section of rectangular wire.
Note: determination of the geometric characteristics of the wire produced in the absence of this exclusion. Ignoring this rule may result in the overloading of electrical circuits or incorrect parameters of its operation.
When you purchase the wire size you can find on the marking. The first number following the letter designation of the type of wire shows its cross section.