19. December 2022

4 Min read

    Contents

      Written by Hermann Christen

      Market Development Manager R&M

      Fiber optic cable for outdoor use

      Fiber optic networks are expanding more and more. They take future broadband supply everywhere. In cities and urban regions, FTTH networks can be quickly installed in roads and canals. Fiber optic cables with a PE sheath are generally well-protected here.

      Today, there are more and more new or expanded fields of application outdoors, in which fiber optic cables are exposed to harsher ambient conditions without being additionally protected. Examples of these fields of application:

      • Aerial deployment: Rural regions want to get broadband into homes using fiber optic aerial deployment and drop solutions. This is more cost-effective than underground cabling. However, aerial cables have to withstand constantly changing weather conditions.
      • Event and sports organizers, broadcasting, and the military are increasingly relying on fiber optics. The cables must withstand changing mechanical loads such as transverse pressure, tension, and friction during laying.
      • The industry is increasingly using pre-terminated fiber optic cables for chemically contaminated environments. In addition, there are other industrial applications in outdoor areas with a lot of dust and dirt, for example.

      That is when the question arises as to which cable material is suitable. Companies are looking for a solution that stands up to all outdoor challenges in the long term. The answer is PUR.

      Polyurethane, or PUR for short, is a highly developed, halogen-free thermoplastic elastomer. It is ideal for cable jackets.

       

       

      Five advantages of PUR cables

      PUR has five major advantages over the regularly used sheath materials polyethylene (PE), polyethylene with flame-retardant additive (LSOH), and PVC. PUR cables are:

      • Mechanically stable. This means abrasion-resistant, impact-resistant, fatigue-resistant, tear-resistant, and cross-pressure-resistant; the soft PUR material acts as padding.
      • The cables remain permanently movable even in low temperatures and freezing temperatures down to -50 °C.
      • Oil, chemicals, UV radiation, etc. PUR is more resistant than standard materials for fiber optic cables.
      • Weather-resistant. PUR cables are suitable for outdoor use in all climate zones, even when exposed to high levels of ozone, salt water, wind, or sunlight.
      • And PUR cables hardly shrink or stretch when exposed to cold and heat, which means less stress for the internal fibers.

      Of course, one disadvantage should also be mentioned here: PUR cables cost more than PE or LSOH cables. And always remember: The well-known standards and directives apply to PUR just as they do to any cable material. This applies to fire behavior, halogen-free behavior, and similar parameters.

      Solutions from R&M

      As an internationally active wire manufacturer with its own production in Europe, R&M offers market-driven PUR solutions. In our cable catalog, you will find twisted-pair patch cords and fiber-optic aerial drop cables with PUR sheathing.

      In addition, the R&M cable catalog provides detailed information on the specifications and coding of the cable products in the «Explanations» section.

      … and recommendations

      For fixed installation cables, R&M recommends using standard cables and also giving them additional protection if necessary. For example, stable ducts, plastic or metal pipes, and reinforcements provide protection. PE and LSZH cables meet the requirements satisfactorily for most purposes in WAN or LAN cabling.

      Companies should consider whether the advantages of the application justify the additional price. In some cases, it is particularly important that the cables are mechanically resilient and can withstand organic liquids over the long term. PUR cables are recommended here. Aerial drop cables with a PUR jacket are recommended for FTTH expansion with aerial deployment.