A Detailed Description About the Self-Regulating Cable

The main
reason why the self-regulating cable is more advantageous than the standard
heating cable is because it cannot get overheated enough to cause damage to
itself. Self-regulating cable systems offer protection against frozen roof
gutters, burst water pipes, snow-covered
walkways etc.  Although very many people
use this heating system in their homes, very few actually know how it works, and in this article, we will show you the magic
behind the working of this cable as well as its main
benefits.

 How Does A Self-Regulating Heating Cable Work?

Self-regulating heating cable, also called Self Regulating heat trace, is designed in such a way that, as it gets hotter, it reduces the amount of electricity flowing in. Although the term self-regulating might seem to suggest that the cable will attain some given temperature and maintain it at that level, it is important to note that the cable only works by limiting the heat flow until at some point below a temperature that would potentially damage the cable. At this point, the cable prevents electricity from flowing through. The best way to describe this system would, therefore, be ‘’self-limiting ‘’.

We will let
you know how this cable work by focusing on the individual parts of this system
and what they do.

Parts of a heating cable

  • Outer plastic jacket– This outer jacket works by
    shielding or protecting the cable against mechanical and moisture damage. It is, however, important to note that the
    plastic outer jacket is not present on
    all heating cables.
  • Inner plastic insulation– This acts as the main layer of insulation (electrical) between
    the outside and the live-current heater. 
    The cable also has bus wires which connect
    the heater to the power source.
  • The conductive core– This is where the real magic of
    self-heating occurs. The conductive core is made of a unique
    plastic material. This plastic is electrically insulating at high temperature
    and conductive at low temperatures. This property of the plastic leads to what is commonly referred to as the positive
    temperature coefficient or simply, the PTC
    element. This means that, as the
    temperature increases, so does the resistance of the cable. To understand this
    better, consider the following equation:

                   R= kT, where T is the temperature, k is a constant
ratio, and R is the resistance. The
actual process is a bit complex, and this
is a simple equation to show you the general idea.

As electricity flows through the plastic material, some of it is absorbed by the resistive plastic, which
turns it into heat. It works the same way as how the tungsten coil absorbs electricity to produce light in an
incandescent light bulb.

The magic behind how the conductive core works

Design and
a good choice of material can be accredited
to the efficiency of this core. It is important to note that, the negative and
positive bus wires don’t touch each other during the action. This means that all the electricity flow
through the core itself.

As the
current flows, microscopic electrical pathways are created and forced to flow
from one bus wire to the other. It is important
to note that, all this happens within the matrix of the core. The small
circuits have some amounts of resistance which combine to form a large heating element. As the core gets heated, it expands and warms up your workload.

However,
the conductive core expands in an irregular
manner and hence creating gaps in the matrix. The created gaps disconnect
or break apart some of the electrical pathways. As
the core gets hotter, it expands more and hence creating more gaps in the
matrix. This means that the number
of complete circuits continues getting
smaller.

As the
temperature continues to increase, many
gaps develop in the matrix until it is impossible for any current to flow
through. At this point, the cable stops generating any heat.

Advantages of the Self-Regulating Heating Cable

  • Temperature regulation– The main advantage of the self-regulating cable is its ability to limit the amount of current flowing
    through it. As we have already explained, as the temperature increases, the
    microscopic electric pathways are broken. This
    increases the cable resistance and hence decreasing the amount of heat
    produced.

The self-regulating
cables are suitable for frost prevention and temperature maintenance because
they produce less heat when warm and more heat when cold.

  • Inherently temperature safe– This is a term used to refer to a
    type of cable that limits its heat production as it approaches temperature
    levels that could interfere with its operation. The self-regulating cable cannot produce heat to the point of damaging itself, and it is
    therefore described as being inherently temperature safe. However, it is
    always advisable to incorporate a thermostat in your heating system especially
    when you are not sure whether your cable is inherently
    temperature safe.
  • Flexibility in installation– These cables can be cut to achieve
    the desired length either during design or in the field. This is because the heating circuit is
    infinitely parallel. This minimizes wastage and also increases
    flexibility during the installation process.

Do I need to incorporate a temperature control system when using this cable?

Like we
have already mentioned, this system works by limiting the amount of current
flowing through the cable. Although there are some cases where you can work
without using a thermostat or any temperature control system, it is not always recommended. Here is a reason why you should use a thermostat or use
any other temperature controller:

  • Accuracy or precision– Please note that these cables are widely used on industrial applications that require a specific temperature optimum level. Although
    these cables are inherently temperature safe, it would be unwise to expect that
    the system would regulate the temperatures to such precise degrees. Incorporating a simple thermostat in
    your system can enable you to achieve the required precisions.

As you can
see, there are so many advantages of using a self-regulating cable over the
standard one. Incorporating a suitable
temperature controller into the system is equally important since it saves you
from unnecessarily losing energy and also from unforeseen mishaps as a result
of using an uncontrolled heating cable.