BS 7671 Regulation 543.1.3 & Formula 543.1.3

Adiabatic Equation Calculator

Calculate minimum protective conductor size (S) or maximum fault duration (t) using S = √(I²t) / k.

Fault Current (I in Amps)

Disconnection Time (t in seconds)

Conductor k Factor

Minimum Calculated Conductor Size (S)

4.13 mm²

Nearest Standard Conductor: 6.0 mm²