Guide

1

Measurement

**diameter and wire****caliper Perform the absence of voltage.Any caliper regardless of whether it is a mechanical or electronic, metal sponge is capable of conducting current.If the wire is coated with a layer of insulation, measuring its section carried out without taking into account its****diameter**well. 2

used to express

**diameter and cross-sectional area of conductors and units of measure in electrical engineering: respectively, millimeters and square millimeters (electricians call them short for "square").** 3

To put in the directory specified wire cross section
mber of "pi" 3.1415926535 (dimensionless).

**his****diameter**, use the following formula: D = 2√ (S / π), where S - area of the conductor (mm²), D - conductor diameter (mm), π - nu 4

for a reverse translation (

**diameter**and in cross-section), use the same formula, transformed as follows: S = π (D / 2) ², where D -**diameter**conductor (mm)S - area of the conductor (mm²), π - number of "pi" 3.1415926535 (dimensionless). 5

cross section stranded wire

**take equal to the sum of the cross sections of the constituent individual wires.Summarize their****same diameter**s pointless.Calculations can be multi-stage.For example, to find an equivalent diameter**stranded wire**, calculate the cross section of one of his veins, multiply by the number, and then put the result back in**diameter**.

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6

Take wire with

**diameter**th or section exceeds the calculated or specified in the table, you can, but too thick**wire**used is inconvenient: they can, for example, to pull out the terminal from the terminal its own weight.Apply the same**wires with a diameter****ohms or less than the calculated cross-section, or can not be shown in the table.** 7

Hollow conductors cylindrical shape (eg, a part of coaxial cables) have a diameter of two

**as: external and internal.According to him, calculate respectively two sections: external and internal.Subtract one from the other, and then place the result in equivalent diameter****.**** **