The Problem Solved
This section is intended to help with your choice of cable, both at the original specification stage and as a post manufactured existing cable. As described in each of the previous sections, the fundamental elements of a cable are quite straight forward and are usually catered for by cables built to a unique Standard and readily available through Wholesalers and Cable Distributors.
However the real world is not as simple and Customers demand innovative Solutions or cost benefits by using more appropriate materials, components and new technology. As we have said many times there is always a Cost/Benefit decision to be taken at each stage of the cable design.
The Environment in which the cable has to work requires that every aspect of the construction of the cable has to be considered from the out set. Consider temperature where both ambient and generated elements will dictate the metal used in the conductors with plain copper conductors being Coated with Tin, Silver and Nickel as the operating temperature of the cable increases typically over 250 Deg C at the top end. Constraints with the more specialised material wires is one of volume versus finished cable demand were cost per kg of metal increases significantly.
The Automotive, Aerospace and Rail Industries need low weight in every component in their construction and reduced conductor cross section are specified to save weight and were power carrying is the function of the cable The smaller section conductor will be required to carry the same current as the higher cross sections thus generating a higher conductor temperature. Reference to any data sheet will tell you the maximum current carrying capacity for a given size. However by the application of new Insulating materials i.e. Teflon or Irradiation cross linked Compounds this combination will operate satisfactorily.
Options
This leads onto the choice of Conductor Insulating in general and here the choice is wide, and as mentioned above data or current carrying capacity and temperature are important initial considerations. However if the cable will have to operate in Damp or submerged environments, then this will influence the choice of Conductor Insulating Material, the application of Water Barrier Compounds or Tapes.
Another consideration important were the accuracy and magnitude of the signal being transmitted is vital to the operation of the equipment it is connecting. Is Mutual Conductance between wires and this can be influenced by the material chosen ie PE performs better than PVC. The radial thickness of the Insulation has a controlling effect, so a PVC Insulation with twice the radial may perform better than PE but at a lower cost.
As we move through the layers of the cable we come to the Outer Jacket were Temperature, Fluid resistance, Flexibility and Mechanical strength will all influence the material most suitable to meet these conditions. With the advent of bespoke sheathing compounds you can usually arrive at an acceptable compromise that gives high performance in a limited (and specified high importance) range of attributes or an average performance across the full spectrum of requirements.
Finally were the environment a cable has to operates has to have a Dynamic performance at low temperatures or be subjected to high flexing cycles. The whole design of the cable has to be considered, from multi strand fine wires, flexible Insulating Material e.g. Silicon/ Rubber, lay-up and bunching configurations, Protective Layers (Fire Survival Cables) Braid or Lap Screens and finally the outer Jacket were low temperature requires a soft Compound(Rubber) but LSZH Materials can result in a stiffer finished jacket.
Conclusions
In Conclusion Environmental considerations create a significant impact on the cable design and whilst there is little opportunity to add these enhancements to completed cable. The use of standard cables made into Bespoke composites does enable some of the attributes required to cope with onerous environmental conditions to be achieved.
Mechanical enhancements are designed to add or improve the cables resistance to physical damage. This process starts with the sourcing of a suitable cable with the appropriate electrical and constructional details i.e. voltage, current, data and core count. The working environment of the cable is then considered e.g. is the cable operating in a static or dynamic installation and are there any external mechanical conditions i.e. Conduit, Ducting. Finally will the finished cable require resistance to Chemicals, Oils, Termites and extremes of temperature.
Having collated all the relevant data we can then decide whether Steel Wire Armouring (Static Installation) or Galvanised Steel Wire Braiding (Dynamic Installation) is appropriate and which sheathing material will meet the external requirements.
Cosmetic enhancements are usually mainly to do with the Final external Sheath and covers the extrusion of the sheath in colour matched compounds to reflect corporate identity or operational/safety colours. Alternatively a transparent sheath can be offered to show the internals of the cable for aesthetic or operational reasons.
Replacing the outer sheath and replacing it with a more appropriate jacket is often possible either by over sheathing or stripping off the existing sheath.
In certain Market sectors, Own Brand printing on the sheath is expected, other sectors find Metre marking useful. This can be achieved either as an in-line process if we are manufacturing the complete cable or as an after service.
We believe that if the End Customer sees a well extruded and informative outer sheath they can expect the same standard on the inside business part of the cable.
Whether you want to convert your existing wires and cables into leads harnesses or retractable coils or commission a Custom made cable especially for the purpose. CDC Ltd has the resources, experience and knowledge to be able to advise what is possible and offer solutions from its extensive range of contacts.
