Formula:

Variables:

• \(I\) = Short Circuit Rating (kA) - Maximum fault current the cable can withstand
• \(S\) = Conductor Cross-sectional Area (mm²) - Cable size
• \(t\) = Duration of Short Circuit (sec) - Typically matching circuit breaker clearing time
• \(K\) = Material Constant - Depends on insulation type

K Values by Insulation Type:

Important Notes:

• Values are for copper conductors only
• Applicable for low voltage cables up to 1kV
• Short circuit duration typically ranges from 0.1 to 5 seconds
• Consider derating factors for ambient temperature and installation conditions