Cable Sizing
Cable sizing is a critical part of electrical design, ensuring cables can safely carry current under real installation conditions. This section covers current-carrying capacity, derating factors, installation methods, and key standards such as BS 7671 and IEC 60287.
You’ll find practical guidance, calculation methods, and engineering insights to help you select the correct cable size for a wide range of applications.
Knowledge Base Topics
Articles
The Adiabatic Equation and k Factor for Cable Thermal Withstand
How to use the adiabatic equation for cable short-circuit thermal withstand calculations, including k factor values and material constants.
Updated June 4, 2026
Cable Thermal Withstand Under Fault Conditions
An overview of cable thermal withstand under short-circuit and fault conditions, including protective device disconnection and related checks.
Updated May 27, 2026
Solar Radiation Effects on Cable Current Rating
Solar radiation effects on cable current rating, including IEC 60287 thermal adjustment and practical derating approaches.
Updated June 4, 2026
Single-Core Armoured Cable Buried Sizing: BS 7671 and ERA 69-30
Buried single-core cable sizing using BS 7671 and ERA 69-30, including why Appendix 4 does not provide all required data.
Updated June 4, 2026
Derating Factors for Cables Grouped in Air
Derating factors for cables grouped in air, including IEC 60287-2-2 reduction factor methods for free-air installations.
Updated June 4, 2026
Cable Troughs: IEC 60287 Temperature Rise Method
A short reference for calculating cable trough air temperature rise using the IEC 60287 empirical method.
Updated May 27, 2026
Cable Sheath and Armour Losses in IEC 60287 Calculations
Sheath and armour losses in IEC 60287 cable current rating calculations, including screen, sheath and armour loss factors.
Updated June 4, 2026
IEC 60287 Cable Current Capacity: Introduction to the Thermal Method
Cable current rating calculations using IEC 60287 thermal balance methods, with a simple cable current capacity worked example.
Updated June 4, 2026
Fictitious Dimensions for Cable Design Calculations
A practical reference for fictitious cable dimensions used in IEC 60502-2 calculations for conductors, cores, screens, sheaths, bedding and armour.
Updated May 27, 2026
Cable Sizing Standards: BS 7671, ERA 69-30 and IEC 60502
An overview of cable sizing standards used by myCableEngineering, including BS 7671, ERA 69-30 and IEC 60502 current rating methods.
Updated June 5, 2026