What is voltage rating?
The voltage rating of a cable is the highest voltage that may be continuously applied to a cable construction in compliance with the relevant cable standard or specification.
Voltage rating figures for cables are normally expressed in A.C. RMS. (Alternating Current Root Mean Square) and are written as a figure Uo/U (Um)
Uo = Rated voltage phase to Earth
U = Rated voltage phase to phase
Um = Maximum system