Earthing Cable Sizing May 2026

| Largest service conductor (AWG/kcmil Cu) | GEC size (AWG Cu) | |------------------------------------------|-------------------| | 2 AWG or smaller | 8 AWG | | 1/0 – 4/0 | 4 AWG | | 250 – 500 kcmil | 2 AWG | | Over 1100 kcmil | 3/0 AWG | Used for large installations (generators, substations, industrial plants).

| Phase conductor size (mm²) | Minimum protective conductor (mm²) | |----------------------------|-------------------------------------| | ≤ 16 | Same as phase | | 25 – 35 | 16 | | 50 – 95 | 25 | | ≥ 120 | 50 | earthing cable sizing

Formula (copper, 1 second fault):

[ S = \frac\sqrtI^2 \times tk ]