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
Cable Fault Calculation Worked Example
Cable fault calculation worked example using complex impedance for phase and earth fault currents.
Updated June 4, 2026
AC and DC Cable Performance Worked Examples
Textbook-style AC and DC cable performance worked examples with equations for temperature, resistance, voltage drop, power loss and indicative life.
Updated June 1, 2026
BS 7671 Voltage Drop Worked Example
BS 7671 voltage drop worked example with equations, substitutions and result for a 50 mm² copper cable.
Updated June 4, 2026
Standard Cable Sizes to IEC 60228
Reference table of standard metric conductor and cable sizes defined by IEC 60228, from 0.5 mm² to 1000 mm².
Updated May 27, 2026
Metric to AWG Cable Size Conversion Table
Metric to AWG and MCM conductor size conversion table with circular mils, stranding and approximate overall diameter.
Updated May 27, 2026
Electrical Resistance: Formula, Temperature Effects and Cable Use
Electrical resistance explained, including resistance formula, temperature coefficient, worked example and use in cable impedance, voltage drop and power loss.
Updated May 27, 2026
Cable Reactance: Inductive and Capacitive Reactance
Cable reactance explained, including inductive and capacitive reactance formulae and their use in impedance, voltage drop and fault-current calculations.
Updated May 27, 2026
Electrical Resistivity: Definition, Formula and Cable Applications
Electrical resistivity explained, including the resistivity formula, factors affecting resistivity and its role in conductor resistance and cable calculations.
Updated May 27, 2026
Cable Inductance: Self, Mutual and BICC Handbook Formulae
Cable inductance explained, including self and mutual inductance, single-phase and three-phase formulae, and BICC Electrical Cables Handbook K values.
Updated May 27, 2026
Conductor Resistance: DC, AC, Temperature and IEC 60228 Values
How conductor resistance is calculated for cable sizing, including IEC 60228 DC values, IEC 60287 AC resistance, skin effect, proximity effect and temperature correction.
Updated May 28, 2026