This standard establishes the rules to determine the rated voltage and the conductor and screen section of cables with a rated voltage equal to or above 0,6/1 kV, with special attention to cables up to 18/30 kV, for 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 under conditions other than the type conditions (see annex A). The power distribution cables that are included in this standard are: Designation Rated voltage Reference standard RHZ1 and HEPRZ1 from 3.6 / 6 kV to 18/30 kV UNE-HD 620 (-9E, -10E) RH5Z1 12/20 kV and 18/30 kV UNE 211620 NOTE Although the intended application of this standard is electrical power distribution cables, in annex A allowable currents have also been tabulated for more sections than those standardized in the aforementioned reference standards. Therefore, the given values of maximum allowable current can be applied, with particular attention to the installation conditions, to cables with similar construction types for industrial applications. 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.