The cables that carry the current are the most important part of the wiring. In order for everything to work perfectly, without short circuits, burnt wires, you need to choose the wiring so that it can withstand the current. And without knowing the cross section of the wire, this cannot be done. If it is insufficient, it will lead to a short circuit and a fire.


  • a How serious is the problem
  • 2 With a stirrup
  • 3 using coils
  • 4 With a ruler
  • 5 With ready-to-use tables

How serious is the problem

For example, you plan to replace all of the electrical wiring in your home. After calculating the expected load, calculating the required wire parameter, go to the store, buy a wire and install the wires. However, once the time has elapsed, the electrical panel is turned off. Turns out the reason was the closure. The reason is in deception.

Sometimes manufacturers provide a product that does not meet the declared characteristics: it is a little smaller. This difference leads to incorrect wiring and the creation of emergency situations. There are several ways to find out the diameter of the conductive part.

With a stirrup

With this measuring device you can measure the diameter. To determine the area of ​​a circle, you need to square this number, multiply by π (i.e. 3.14) and divide by 4. This procedure is one of the simplest and only takes not much time and effort. However, you need to measure the diameter with a vernier caliper very carefully and accurately. Even a small error at the end will lead to the fact that the cross section will be calculated incorrectly.

using coils

For this method of measurement, a pencil, pen and ruler are suitable. Before measuring the wire, you need to remove some of the insulation from it. Then you need to take a pencil or pen, wrap the measured material around it. The coils should fit snugly together. The more turns you make, the more accurate the result will be. Their minimum number is 10. After counting the number of turns, you need to write it down and use a ruler to measure the total length of the turns. The resulting number must be divided by the number of turns. This method of measurement can only be accurate if the coils are tightly wound.

With a ruler

To measure with a ruler, only a thick thread is taken: the smaller the thickness, the greater the error. The desired parameter can be determined with a wire or paper; with the second option, the accuracy of the measurement will be greater. First you need to tear off a small strip of paper and fold it to one side. It is best to use thin paper. Then tie it to the wire and wrap it around the circumference until it touches the band. In this place, it must be folded a second time and attached to the ruler. Warning: the accuracy of this method is the lowest. It can be used if there are thick aluminum wires. Not suitable for copper wiring.

With ready-to-use tables

This method is best suited for standard gauge conductors. Measurement charts can be taken from physical reference books. Measuring the cross section of a stranded wire First you need to remove a little insulation, disconnect all the wiring. Measure the diameter of a strand. Knowing their number, it is easy to calculate the total cross section of the measured material. Wires are not always tightly connected. There is often an air gap between them. In this case, the result can be multiplied by 0.91.

Cross section measurement is an important procedure before wiring and other types of repair work. It is necessary to approach this stage with responsibility, since even a small mistake can ultimately lead to the most adverse consequences, up to a fire.