Symbol Used in Harmonized System
  Color of cores and outer sheaths
  Voltage Drop
  Voltages
  Convertions Factors for Current Carrying Cap...
  Construction Components and Rated ...
  Capacity of Cable Drums
 
 

Voltages

 

Rated Voltages

Cables are classified by the rated voltages Uo/U.
Uo: The voltage between the conductor and earth or earthed mettalic cover (concentric conductor, screen, armouring, metalsheath).
U: The voltage between two phase conductors.
The standard rated voltages employed ın three-phase systems in compliance with TSE-IEC-VDE and BS are accordingly:
Uo/U = 0,6/1; 3,6/6; 6/10; 8,7/15; 12/20; 18/30; 20,3/35 Kv

In three-phase AC installation systems, the rated voltages:


Uo=U/√3

In single-phase AC systems where both conductors are insulated from earth, or DC systems, the rated voltages:

Uo=U/2

In single phase AC systems where one conductor is earthed or DC systems, the rated voltages:

Uo=U

Operating voltages

In DC systems having a cable with Uo= 0,6 kV, the maximum permissible operating voltage is:

Um= 1,8 Kv

The maximum permissible operating voltages (Um) for single-phase or three-phase AC systems are described in the table on next page.