The most important thing when installing electrical wiring is to choose a high-quality cable, because you can always easily replace a socket or switch, and replacing a burned-in cable will be difficult, not to mention the consequences of this. Very often, the cable cross-section differs from the one declared by the manufacturer, because reducing the cross-section allows unscrupulous manufacturers to save on the most expensive component - copper. In order not to become a victim of fraud, it is advisable to measure its cross-section yourself before buying a cable, and determine the cable cross-section by diameter in three simple ways using the application.

For the first two methods, you will need a caliper or micrometer.
        It is necessary to measure the diameter of the cable core (wire) without insulation and enter in the Enter diameter (mm) field.