ABSTRACT
Typically, a load of about 30 watts per foot from a cable or duct bank are sufficient to dry such sand to near zero percent moisture where the rho can rise to 350 to 400.
Thermal runaway conditions of native soils have been experienced by many utilities involving transmission cables as well as single-circuit, direct buried distribution feeder cables. In one situation, the sand had less than one-half percent moisture adjacent to a direct buried feeder cable exiting a substation even though lawn irrigation sprinklers were only two feet above. With four hours of watering every night, the sand could not retain enough moisture to prevent thermal runaway of one buried three conductor 500 kcmil copper feeder cable. The pattern of eccentric circles of dry sand was found to be in complete agreement with the paper of Balaska, Merrell, and McKean [14-9] that described a simulated transmission cable in a sand hill in New York.
