Earth Fault Loop Impedance Calculator

Once $Z_s$ is determined, the prospective fault current ($I_pf$) is calculated using Ohm’s Law:

: External Earth Fault Loop Impedance (the impedance of the supply side outside the installation). R1cap R sub 1 : The resistance of the line (phase) conductor. R2cap R sub 2 earth fault loop impedance calculator

Resistance increases with temperature. Most calculators apply a (typically 1.2 or the "80% rule") to account for the fact that cables are cooler during testing than they will be when running at full load. Key Features to Look For When choosing an online or app-based Zscap Z sub s calculator, look for these features: Once $Z_s$ is determined, the prospective fault current

Standard resistance values are usually quoted at $20^\circ\textC$. During a fault, current generates heat, raising the conductor temperature. Regulations require calculations to be based on the "worst-case" scenario where conductors are at their maximum operating temperature (e.g., $70^\circ\textC$ for PVC insulation). Most calculators apply a (typically 1