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
IEC 60502 vs IEC 60840: Power Cable Standards Compared
IEC 60502 vs IEC 60840 comparison for power cable standards, including voltage range, application, testing and construction differences.
Updated June 4, 2026
Economic Optimisation of Cable Size: Life-Cycle Cost and Losses
Economic cable sizing balances installed cost against the present value of Joule losses over the cable life.
Updated June 4, 2026
Dielectric Loss in Cables: Tan Delta and Capacitance
How dielectric loss is calculated in AC cables using tan delta, capacitance and IEC 60287 voltage thresholds.
Updated May 27, 2026
Radiation in Cable Thermal Analysis
Thermal radiation in cable and busbar thermal analysis, including surface radiation and enclosure heat-transfer equations.
Updated June 4, 2026
Convection in Cable Thermal Analysis
How convection is represented in cable thermal analysis, including Newton cooling, effective conductivity and enclosure correlations.
Updated June 4, 2026
Cable Thermal Analysis: Heat Flow, Losses and FEA
Introduction to cable thermal analysis, including heat-flow equations, cable losses, boundary conditions and finite element analysis.
Updated May 27, 2026
BS 7671 Voltage Drop Calculations
How to calculate cable voltage drop using BS 7671 Appendix 4 mV/A/m tables, correction factors and impedance conversion.
Updated May 27, 2026
Voltage Drop Calculations for Cable Sizing
Voltage drop calculations for cable sizing using CENELEC TR 50480, including d.c., single-phase and three-phase systems.
Updated June 4, 2026
Non-Adiabatic Effects in Cable Short-Circuit Calculations
Non-adiabatic effects in cable short-circuit calculations, including the IEC 60949 correction factor method.
Updated June 4, 2026
I²t Cable Thermal Withstand and Energy-Limiting Devices
How to compare protective device I²t let-through with cable thermal withstand, including energy-limiting device data and the k²A² check.
Updated June 4, 2026