The maximum allowable current of a conductor depends upon the wire size. For a higher diameter of wire size, the conductor can carry more current depending on the conductor material. Similarly, the maximum allowable voltage drop by the wire depends upon the length of the wire. These parameters should be considered while calculating the wire size. Use the online electrical wire size calculator for calculating wire size either in metric (SI) and British system.
The Allowable Voltage Drop of Wire.
When current flows through a wire, heat is produced. A higher current produces a higher heat depending upon the specific resistance of the material and wire size. Even though the resistance of a conductor is very low but still it produces heat and causes a voltage drop. Therefore, for higher current, a high gauge wire is selected to reduce the power loss due to heat and the voltage drop. The maximum allowable voltage drop from a source point to load is 2.5%.
Temperature and Resistance
Due to the collision of charge and the fraction to the current flow, every current-carrying conductor produces heat. While continuous heat generation can add up and cause big problems. For a high-temperature conductor, the current carrying capacity of the conductor decreases. Similarly, a low diameter wire can produce more heat and vice versa.