Construction of cable cores according to IEC 60228

According to IEC 60228, conductors of insulated cables are subdivided into 4 classes.

These conductors include solid and stranded copper, aluminium and aluminium alloy conductors incables for fixed installations and flexible copper conductors.
  • Class 1: solid conductor, the core is formed by one single wire with a diameter up to 6 or 10 mm2 (also denoted by the letter U)
  • Class 2: stranded conductor intended for fixed installation: for cores with a diameter over 6 or 10 mm2, the core is usually formed by a plurality of thin wires (also referred to by the letter R)
  • Class 5: flexible conductor: the core is formed by a large number of thin wires
  • Class 6: very flexible conductor.