Splendid insulations: art merges with science

Surrounding the core with added-value

WANTED: just the right wrapping

InsulatingFinding just the right insulation around a metallic or optical core is a science and a practical art which brings together knowledge about polymers, and how they are formulated and processed.

If the only concern were electrical insulation, the cable industry could have merely relied on “commodity materials” like mass-impregnated paper-insulated insulations which were long used for HV underground and submarine power cables, and still are. However, today, cross-linked polyethylene (XLPE) has largely replaced paper since it is durable, flexible and tolerates temperatures of ≤120ºC.

Over the years, our downstream partners needed cables which could survive in extreme conditions where insulation took on a new dimension, far beyond the prevention of “electrical leakage.”

Insulating at extreme cold and hot temperatures is now a must. That is why synthetic rubber elastomers and polymeric alloys are increasingly used.

For example, our ICEFLEX™ cables – developed by our Korean company, Kukdong and the French Nexans Research Center in Lyon – are ideal for freezing arctic conditions in shipboard and oil & gas applications.

At the other extreme, high-temperature cables must be insulated with Poly Ether Ether Ketone (PEEK) or fluoro-based polymers (PTFE/Polytetrafluoroethylene). These insulations assure endurance and safety in aerospace and plenum LAN applications, in addition to many others.

Moreover, since each application has a specific chemical environment, polymer insulations must resist a wide diversity of threats: from simple hydrocarbon fluids to alcohols and other invasive substances. Urethanes, polyamides, polyamines and special polymers make these cables safe for conditions like those that prevail in modern petrochemical plants.

One major threat for polymer is fire. To continue functioning during an emergency, insulations must lose their malleable characteristics and transform themselves into a stiff ceramic-like shield which can resist extreme temperatures and keep vital data and energy flowing. This is achieved through Nexans’ unique INFIT™ technology.

Finally, air can be used as a very efficient insulator in some circumstances because of its dielectric qualities, especially where high-speed data transmission is involved.

Profile insulation” is a patented extrusion technique where the insulation geometry is contoured. The resultant shape – which is not unlike the spiraling column of a gothic cathedral – provides structural support to the insulated wire in a twisted-pair construction. This significantly improves signal strength on standard LAN cables. In addition, “grooved” insulations also reduce insulation material by 10–30% and increase signal speed.

Thus, art and design often merge with science and engineering to improve the performance of Nexans insulations in many new and challenging environments.