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Calculated Operating Temperatures of Thermally Insulated Electric Cables.



D. D. Evans


Steady-state operating temperatures of current-carrying electric cables buried axially in cylinders of thermal insulation were calculated. Combinations of six types of nonmetallic electric cable, two thermal insulation materials, five thermal insulation thicknesses and a range of currents both greater and less than the typical rated service currents for the cables were studied. These calculations show that thermally insulated electric cables carrying the rated current may exceed the rated operating temperature limit for common cable jacket materials.
Technical Note (NIST TN) - 1133
Report Number


electric cable, electrical fire, models, thermal insulation, wiring system


Evans, D. (1981), Calculated Operating Temperatures of Thermally Insulated Electric Cables., Technical Note (NIST TN), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed June 23, 2024)


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Created January 1, 1981, Updated November 10, 2018