The requirements of this International Standard are intended to provide for a satisfactory life of conductors and insulation subjected to the thermal effects of carrying current for prolonged periods of time in normal service. Other considerations affect the choice of cross-sectional area of conductors, such as the requirements for protection against electric shock (see GB 14821.1), protection against thermal effects (see GB 16895.2), overcurrent protection (see GB 16895.5), voltage drop (see section 525 of GB 16895.6), and limiting temperatures for terminals of equipment to which the conductors are connected (see section 526 of GB 16895.6).
For the time being, this standard relates only to non-armoured cables and insulated conductors having a nominal voltage not exceeding 1 kV a.c. or 1,5 kV d.c. This standard does not apply to armoured single-core cables.
NOTE – If armoured single-core cables are used, an appreciable reduction of the current-carrying capacities given in this standard may be required. The cable manufacturer should be consulted. This is also applicable to non-armoured single-core cables in single way metallic ducts (see 521.5 of GB 16895.6).
Forward
IEC FOREWORD
523.1 General
523.2 Ambient temperature
523.3 Soil thermal resistivity
523.4 Groups containing more than one circuit
523.5 Number of loaded conductors
523.6 Conductors in parallel
Annex A
Annex B
Annex C
Bibliography
