Sizing of Ground Conductors Against Fusing

The correct evaluation of I2R heat, absorbed during a fault, is the most critical factor in determining the adequate size of a grounding conductor. This paper presents a general method for calculating and comparing the short-time ampacities of modern conductors made of copper clad steel, aluminum clad steel and galvanized steel, aluminum and aluminum alloys, etc. For copper, a direct correspondence is established between the general formula and the existing Equation No. 12 of IEEE Std. 80-1976