This standard establishes the rules to determine the conductor section of the cables with a rated voltage equal to 0.6 / 1 kV, for electric power distribution circuits. Starting from some installation conditions considered as type, the admissible currents in permanent regime for cables in common use and the correction factors are tabulated to calculate the admissible currents in conditions other than the type conditions (see annexes A, B, C and D). The power distribution cables that are considered in this standard are: Designation Reference standard RV UNE-HD 603-5N XZ1 (S) and XZ1 (AS) UNE-HD 603-5X RZ UNE 21030-1 for Al UNE 21030-2 for Cu NOTE Although the intended application of this standard is electrical power distribution cables, the Annexes have also tabulated allowable currents for more sections and types of conductor than those standardized in the aforementioned reference standards. Cables for special applications that have their own application regulations, such as cables for ships, mines, submarines or for nuclear power plants are not considered in this standard.