An analytical solution of heat flow versus wire temperature for electric cables buried in plaster

Complete electric heating installations are becoming quite general throughout certain areas. A popular type is the resistance cable embedded in plaster to form a radiant panel heater. For long cable life and maximum safety, the cable temperature must not exceed a definite limit. Various investigators have derived equations describing the temperature throughout the panel. However such equations do not relate temperature to heat input or else they are based on conditions not met in electric cable heating. K. Kalous1 developed equations for embedded pipe using hot water based upon the simplified assumption that heat flows laterally through the panel. This assumption is valid for panel thicknesses near pipe diameter and for pipe spacing, which is large when compared to panel thickness. Neither condition is met in electric cable heating. T. Napier Adlam2 publishes curves for pipe buried in plaster. The pipe sizes and spacings however, are quite large as compared to electric cable sizes and cable spacing.