Self-regulating cable has the characteristics of “artificial intelligence” because its heat dissipation is influenced by the ambient temperature. Modern advances in science and technology have made it possible to obtain a heating system design element that, as the ambient temperature increases, the heat output released decreases, and as the ambient temperature decreases, it increases. In this case, the heat release in each section of the cable is determined by the ambient temperature without additional control devices and does not depend on the condition of adjacent sections.
Self-regulating cable has a design feature – it is a special heat-generating polymer matrix with conductive inclusions made of carbon material. A drop in temperature leads to compression of the matrix material, thereby increasing the number of conductive paths, which increases the heat dissipation of the cable. As the ambient temperature increases, the matrix material swells, leading to a break in the connections between the inclusions and a reduction in the number of conductive paths, which in turn leads to a reduction in heat generation. Thanks to such a device, the self-regulating cable adjusts to the ambient temperature with each of its sections.
Self-regulating cable principle of operation
Self-regulating cables consist of two conductive parallel copper wires. They are multi-conductor, generally having 17-19 wires. The most acceptable coating for the wires is nickel, which prevents oxidation and aging. The matrix and conductive cores are covered with an inner insulating layer, and a shield is placed over it. This multilayer structure is covered from the top with a plastic protective coating. The two insulating layers used provide an increase in the cable’s dielectric strength, protection against shock loads and negative environmental influences.
The cable’s outer sheath, braid and inner insulation provide mechanical, chemical and electrical protection… but the “magic” happens in the conductive core of the heating cable.The cable’s outer sheath, braid and inner insulation provide mechanical, chemical and electrical protection… but the “magic” happens in the conductive core of the heating cable.
A. Low ambient temperature = High heating power
If the temperature in the immediate vicinity of the self-regulating heating cable is low, its heating power increases. The polymer chains of the cable’s core shrink, causing many electrical connections to form between the embedded carbon molecules.
B. Moderate ambient temperature = Low heat output.
In response to the increased ambient temperature, the heating power of the self-regulating heating cable decreases. The polymer chains of the cable’s core expand, reducing the number of electrical connections.
C. High ambient temperature = Virtually zero heating power
If the ambient temperature of the heating cable reaches a high level, its power drops to practically zero. Due to the maximum degree of chain expansion in the polymer core of the cable, there are virtually no electrical connections. The self-regulating heating cable adjusts its heating power along the length of the entire cable. This makes such a system a safe and reliable solution for many applications.
- The nVent RAYCHEM company is the inventor of self-regulating heating cables and a world leader in this field.
- Self-regulating heating cables can cross and touch each other without burning out!
- Self-regulating cables can be cut to the appropriate length on site, giving full flexibility in situations where the installation design deviates from the actual site situation.
Self-regulating heating cables and applications
The self-regulating heating cable industry is very broad, ranging from construction (floor heating, driveways, ramps, gutters) to the chemical and petrochemical industries. It counts hundreds of different specialized models of which the ordinary person is not aware.
Self-regulating heating cables differ in min:
- supply voltage,
- heating power,
- chemical resistance,
- mechanical resistance,
- minimum installation temperature,
- maximum interaction temperature,
- Withstand high temperatures (up to 600°C),
- external insulation,
- The ability to work in a hazardous area.