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Self-regulating cables

Elec-Trace is a premier manufacturer of self-regulating cables. Only a few companies have the technology to produce self-regulating cable.

Self-regulating heating cable varies its heat output in relation to the ambient temperature. As the surrounding temperature increases, the heat output of the PSR cable decreases; however, when the temperature decreases, the cable heat output increases and provides the heat needed along the length of the cable.

An Easy Explanation of this Unique Type of Cable:

Self-regulating cable uses two parallel bus wires which carry electricity but do not create heat. They are encased in a semi-conductive polymer. The cables are extruded and then irradiated to cross-link the polymer and hold the shape. This polymer is loaded with carbon particles which conduct electricity between the bus wires. As the polymer core warms, it expands and the carbon particles spread apart reducing electrical paths and therefore current flow.

By varying both the carbon content and distribution, different cables with different output characteristics can be produced. In addition, there is an inner jacket which separates the bus wires from the grounding braid. In commercial and industrial cables, an additional outer jacket of rubber or Teflon® is applied.

Benefits:

Uses:

The most common pipe trace heating applications include:

Other uses of trace heating cables include:

Freeze Protection:

Every pipe or vessel is subject to heat loss when its temperature is greater than ambient temperature. Thermal insulation reduces the rate of heat loss but does not eliminate it. Trace heating maintains the temperature above freezing by balancing heat lost with heat supplied. Normally, a thermostat is used to energize the cable when it measures the temperature falling below a set temperature value, usually between 3°C and 5°C, and is often referred to as the “set point.” The thermostat will de-energize the heat trace when it measures the temperature rising past another set temperature value, usually 2°C higher than the set point value.

Gutter and Roof De-icing:

Placement of heat trace cable on roofs or in gutters to melt ice during winter months. When used in gutters, the cable is not meant to keep the gutters free of ice or snow, but only to provide a free path for the melted water to drain off the roof and down the downspout or drain pipe. A thermostat is used to energize the cable when it measures the temperature falling below a set temperature value, usually between 3°C and 5°C, and often referred to as the “set point.” The thermostat will de-energize the heat trace when it measures the temperature rising past another set temperature value, usually 2°C higher than the set point value.

Slab De-icing:

Heat trace cable can be embedded in the concrete of a ramp to keep it free of ice. A thermostat is used to energize the cable when it measures the temperature falling below a set temperature value, usually between 3°C and 5°C, and often referred to as the “set point “ The thermostat will de-energize the heat trace when it measures the temperature rising past another set temperature value, usually 2°C higher than the set point value.

Process Temperature Maintenance:

Hot water service piping can also be heat traced so that a circulating system is not needed to provide hot water at outlets. The combination of heat tracing and the correct thermal insulation for the operating ambient temperature maintains a thermal balance where the heat output from the heat trace matches the heat loss from the pipe. Self-limiting or regulating heating tapes have been developed and are very successful in this application.

A similar principle can be applied to process piping carrying fluids which may congeal at low temperatures; for example, tars or molten sulfur. High-temperature heat trace elements can prevent blockage of pipes.

Industrial applications for heat tracing include chemical plants, oil refineries, nuclear power plants, food manufacturing facilities – virtually any place where fluid flows in a pipe. For example, wax is a material that starts to solidify below 70 °C which is usually far above the temperature of the surrounding air. A pipeline used for liquid wax must be provided with an external source of heat to prevent the pipe and the material inside it from cooling down.