Abstract: Heat tracing of an elongate, thermally-insulated substrate is effected by means of one or more elongate, constant wattage electric heaters mounted in thermal contact therewith beneath the thermal insulation. A metal conduit is mounted on the substrate and extends away therefrom out through the thermal insulation. The or each heater extends from the substrate through the conduit and is connected to a source of electric power within an external junction box. By this arrangement, the heat developed along the length of the constant wattage heater as it passes through the thermal insulation of the substrate can be dissipated safely through the body of the conductive conduit.

Abstract: Heat tracing of an elongate, thermally-insulated substrate is effected by means of one or more elongate, constant wattage electric heaters mounted in thermal contact therewith beneath the thermal insulation. A metal conduit is mounted on the substrate and extends away therefrom out through the thermal insulation. The or each heater extends from the substrate through the conduit and is connected to a source of electric power within an external junction box. By this arrangement, the heat developed along the length of the constant wattage heater as it passes through the thermal insulation of the substrate can be dissipated safely through the body of the conductive conduit.

Abstract: An apparatus for preventing the formation of ice on a substrate exposed to an outdoor environment or for preventing condensation of moisture in a cabinet for electrical equipment includes a sensor for measuring the temperature of the ambient air around the substrate or around or in the cabinet and calculates the rate of change of the temperature of the ambient air. The apparatus further includes a sensor for measuring the temperature of the substrate or of a surface of or inside the cabinet. A heater supplies heat to the substrate or cabinet in response to pre-arranged conditions dependent on the outputs of the sensors and on the calculated rate of change of the temperature of the ambient air. The apparatus for preventing condensation may optionally omit the sensor for measuring the temperature of a surface of or inside the cabinet.

Abstract: An apparatus is provided for preventing the formation of ice on a substrate exposed to an outdoor environment or for preventing condensation of moisture in a cabinet for electrical equipment. The apparatus includes a sensor for measuring the temperature of the ambient air around the substrate or around or in the cabinet, means for calculating the rate of change of the temperature of the ambient air, a sensor for measuring the temperature of the substrate or of a surface of or inside the cabinet, and a heater arranged to supply heat to the substrate or cabinet in response to pre-arranged conditions dependent on the outputs of the sensors and on the calculated rate of change of the temperature of the ambient air. The apparatus for preventing condensation may optionally omit the sensor for measuring the temperature of a surface of or inside the cabinet.