Geoff Day, Technical Manager at CMS plc.Managing the physical cable in a communications room or Data Centre shouldn’t, on the face of it, seem too daunting, but in practice, it can present plenty of challenges along the way. There are a number of factors that need to be taken into consideration when mapping how cables are routed and organised. If insufficient consideration is given to cable management as part of the planning process, which sometimes happens, this can result in problems post-installation. Investment in the planning and implementation of robust cable management can ensure a system that is easy to both maintain and expand at a future point in time.
So what are the elements we need to consider when planning for good cable management?
Cable properties
Firstly, we need to be cognisant of the impact of poor cable management on the cable itself. Whenever a cable changes its direction, any bends, kinks, or twists in the cable can impact on its electrical properties, ultimately affecting its overall performance. This applies whether using copper or fibre cable and is the reason why it is essential that bend radius parameters should be adhered to.
Infrastructure and Environment
The building infrastructure will impact on the cable management planning and implementation process. New buildings can effectively, be regarded as “green-field” sites as far as the communications room and cabling are concerned. They will still require careful planning but there will be no incumbent hardware or containment to deal with. Refurbishments can often prove more challenging: with floor or ceiling cavities, cables and containment in situ, that can’t always be removed. These can impact on the containing and routing of new cables, and, as most seasoned installers will know, existing cables aren’t always removed.
Cabling Standards
There are a number of industry standards that need to be followed: all of which include recommendations on the treatment of cables in installation. These include:-
BS6701 – Telecommunication Equipment and Cabling
EN50173, ISO11801, ANSI/TIA/EIA-568-B – Generic IT cabling for Customer Premises
EN50174 – IT Cabling Installation
EN50130 - Bonding & Earthing in buildings with IT Equipment
ISO/IEC TR14763-2 – Implementation and operation of customer premises – part 2 Planning & Installation
In addition to this there is TIA-942 which is the Telecommunications Infrastructure Standard for Data Centres and ANSI/TIA606-B which is the administration standard for telecommunications infrastructure, which covers labelling, which is an integral part of cable management.
The standards are designed to cover all potential eventualities in real-world installations and it is most likely the combination of the standards, combined with the variety of different building infrastructures and layouts that have led to the plethora of cable management products that are available on the market today.
Best Practices for Cable Management
It isn’t possible within the confines of this article to cover all the details documented in the standards, so I will cover what I deem to be the most pertinent points.
- • Services need to be separated – power and data cables need to be separated and the standards provide detail on the separation distances and how cables should be kept apart. There are different parameters for separation dependent on the cable construction and containment used.
- • Cables must be earthed and bonded
- • Adequate containment for the cables should be provided either overhead or under a raised floor
- • Containment can be either: a solid plastic structure which fits together to create a pathway or a metal framework that can be cut and shaped to create a pathway
- • Sufficient space should be left in containment to allow for future expansion
- • Service loops should be provided on the network to allow the installer to: work at a convenient location to reconfigure hardware or re-terminate cable. If possible service loops should be stored on the containment on dedicated tray work.
- • In the case of Data Centres and in accordance with the TIA-942 standard
- • They must be designed with separate racks and pathways for each media type.
- • Data and power cables must be placed in separate pathways or separated by a physical barrier
- • Sufficient space must be provided between racks and cabinets and in pathways for better cable management, bend radius protection and access.
- • Don’t forget that patch cords need to be managed within the rack space
Cable Management products
Again it isn’t possible to cover all the available cable management products in this article, but I have highlighted some key products which form an integral part of most typical installations.
Cable Management Checklist:
I have listed below a few of my top tips for cable management
- • Don’t skimp on planning and implementing cable management, if you do it will come back and bite you later!
- • Always conduct a thorough site survey as this will highlight any unusual cable management needs
- • Think about the infrastructure and environment you are working in
- • Ensure you are aware of all the standards requirements
- • Never fill containment – it should not be more than 50% full
- • Choose the right containment for the cable you are using
- • Good labelling is a critical part of cable management
Containment
Selecting the right containment for the cable you are using it critical and there are many different options available on the market including solid metal, mesh metal, plastic raceway and trunking. Metal containment is typically used for copper cables and the cable type will determine the level of cable separation required within the containment. Plastic raceway is typically used for fibre cable containment.
Trunking is generally used where there is insufficient space below floor or above ceiling but is not the first choice for containment as it is somewhat more intrusive. At CMS plc we have recently uncovered a niche application, in secure environments, for clear trunking for applications where the cables need to be visible to the network manager.
Above- the- rack containment
Above-the- rack raceways offer Network and Data Centre managers more options for cable routing in the communications room or Data Centre. Using roof- mount raceways frees up under-floor areas and helps to improve cooling efficiency, which is particularly important in a Data Centre application. The installation of fibre cables above the rack is becoming increasingly popular, but it isn’t confined to fibre, it can be used for copper too. Often these raceway products can be attached via the rack, negating the need for any ceiling fixtures.
In-rack cable management
In recent years there has been a dramatic increase in the number of different cable management products for use in racks: this has primarily been brought about by the increase in the number of Data Centre installations: where space is at a premium, cables are densely packed and network performance is critical. For many years horizontal rack managers were the only product in town: now there are horizontal rack managers, vertical rack managers in a whole variety of shapes and sizes all designed to contain cables whilst maintaining that ever-important bend radius requirement.
The other stuff
Then we have a huge range of other cable management products which all have their own unique features making them ideal for specific applications. Traditional cable management products which have been around for many years include: floor boxes, data grommet boxes, flexible conduit, cable ties and grips, cable matting. Many of these products are simple in their construction but still widely used today alongside the newer products that have been designed specifically for the Data Centre environment.
