What Is The Wire Squared And How To Calculate It?

- Aug 22, 2018-

Actually, the square of the cable is the cross-sectional area of cable, which is the area of the circular cross-section of cable, its unit is square millimeters.

Generally, when network voltage is 220V, and the current rating for per square cable is about 1 kilowatt.

Each square of copper wire can live 1-1.5 kilowatts, and the aluminum wire can live 0.6-1 kilowatts per square. Therefore, it is sufficient to use only one square copper wire for an electric appliance with a power of 1 kW.

Regarding the electric current, power transmission for the short-distance, generally, per square of copper wire can live 3A to 5A. The good heat dissipation condition is 5A/mm2, which not good is 3A/ mm2.

Conversion method:

Knowing the square of the wire, calculate the radius of the conductor using the formula for the circular area:

Square of wire (square millimeters) = pi (3.14) × square of conductor radius (mm)

Knowing the square of the wire, the same is true for calculating the conductor diameter, such as:


The wire diameter of the 2.5 square wire is 2.5 ÷ 3.14 = 0.8, and the square root is 0.9 mm, so the conductor diameter of the 2.5 square wire is 2 × 0.9 mm = 1.8 mm.


Knowing the diameter of the conductor, calculating the square of the wire is also calculated using the formula for the area of the circle:


Square of wire = pi (3.14) × square of conductor diameter / 4

The cable size is also nominally squared, and the multiple strands are the sum of the cross-sectional areas of each conductor.


The formula for calculating the cross-sectional area of the wire:

0.7854 × square of wire diameter (mm) × number of shares

For example, 48 strands (wire diameter 0.2 mm per strand) 1.5 square wire:

0.7854 × (0.2 × 0.2) × 48 = 1.5 square.