Control of thermal environment of buried cable

THE OPERATING TEMPERATURE of underground current-carrying conductors is affected directly by the thermal resistance and capacitance of their immediate environment. With pipe-type or directly buried cable, where soil alone comprises that environment, the thermal characteristics of that soil are of major importance. Soils vary considerably in respect to these characteristics, even in a given locality, and along the route of a cable line several miles in length, the range in values usually will be appreciable.