talking point Management styles


Paul Courson of Cablofil argues that specifying the right cable management system makes for easier maintenance and greater data centre efficiency.


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n amongst all the multi- million pound hardware, the sophisticated security systems and the super efficient cooling systems, it’s easy for specification of the cable management system in a data centre environment to seem like a peripheral issue. However, it can affect ease of access for maintenance; ease of reconfiguration or retro-fitting of additional systems, cooling load and energy consumption requirements and play a business critical role in protecting cables. These days, even when there are big budgets involved, everybody is concerned about costs and often that means that specifiers shop around. When it comes to cable management systems, it’s essential to consider costs not just on the basis of purchase price, but also on the criteria of installation times, product wastage, future flexibility and suitability for application.


In general terms, a steel wire basket tray system offers the best value, not only because it uses less steel than traditional perforated steel tray but also because it is quicker to install and allows an installation to be modified easily. However, not all steel wire systems are the same, and quality counts. A better quality system will offer better load bearing capabilities, greater durability, a wider range of brackets, couplings and accessories and a design led approach that provides solutions that answer the end user’s requirements. For example, one of the issues for data centre applications is the possibility of business critical cabling being snagged on the edge of the steel wire tray during installation/ commissioning or maintenance. For this reason, specifiers should always look for a cable management system with a rounded ‘safety edge’ to prevent this happening. The cable management system is not


designed merely to contain the cables but also to protect them. Unfortunately, the


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task of protecting the cables is complex: use a system that is too enclosed and the cables will be difficult to access for maintenance purposes and may overheat, potentially affecting the integrity of the cables over time. To illustrate this point, recent comparative tests were carried out in order to demonstrate the effects of a steel wire tray cable management system as compared to perforated steel tray, metallic trunking, plastic trunking and metallic conduit. Carried out by world renowned, independent laboratory, Bureau Veritas: LCIE, the tests used rigs of 100mm and 300mm widths of the various containment systems and measured both the core temperature of the cables and their resistivity during the course of the tests. On both tests, the natural ventilation of the steel wire basket tray ensured that the cable cores remained at a lower temperature than any of the other systems.


The tests also demonstrated that the natural ventilation offered by steel wire tray systems ensures reduced resistivity (due to the reduced temperatures of the cable cores). The steel wire tray again registered the lowest readings at 5.0mΩ for the 100mm rig and 19.5mΩ for the 300mm rig, demonstrating that the natural ventilation of a steel wire tray system reduces the amount of energy consumed by avoiding wasted energy. While the test results outlined above are compelling, many specifiers still insist that the use of matting is necessary to prevent the perceived risk of pressure marks on the cables.


In fact, the mesh like structure of steel wire tray is designed to distribute the weight of the cables evenly across the tray so that there is never any risk of pressure marks. This has been proven in independent reliability and durability tests conducted by Intertek Testing Services, which concluded that cables are at no greater risk of pressure marks with tray


alone than with tray and matting. What’s more, the same tests revealed that cables are actually likely to perform better without the use of matting because the matting inhibits the steel wire tray’s natural ventilation properties. While the matting debate continues concerns about ‘zinc whiskers’ presents another contentious subject for the data centre sector. This phenomenon involves the possibility of microscopic particles of zinc which separate from zinc electroplated steel materials and could contaminate the atmosphere. According to the theory, these particles, if not filtered out by the air handling units, could come to rest on an exposed circuit card causing a short circuit and equipment failure. There are two key points to consider: firstly from our 15 years’ experience in data centres, as far as I know there are no cases where there has been a problem caused by zinc whiskers; secondly the cable management system is not likely to be the only zinc electroplated material in the data hall. Nevertheless, where there is even the smallest possibility of business critical risk, there should be a solution. In this case, that solution is to use a powde coated steel wire tray system, which completely seals in the zinc-electroplating so that there can be no risk of zinc whiskers from the cable management system. This option can also provide benefits in terms of management and maintenance as the powder coating allows colour coding of the cable management infrastructure for easy identification of different networks for isolation or maintenance. Steel wire tray remains the cable management system of choice in data centre environments and its growth in popularity mirrors the ascendance of the data centre sector. Cable management specialists are clearly focused on addressing sector specific issues – whether perceived or proven – playing a vital role in its operational efficiency.


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