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Initiation responsibility: Network planner; Head of IT Section; Head of Site Technical Service
Implementation responsibility: Site technical service
When planning cable routes, attention must be given to avoiding identifiable sources of danger. As a general rule, cables should be routed only in areas which can be accessed exclusively by the user. It is easier to control routing if the line layout is clear. Routes and individual cables should always be run in such a way that they are protected against direct damage by persons, vehicles or machines.
Sites for equipment should be selected so that the cables are not run in areas through which people walk or drive. If this cannot be avoided, cables must be protected against the anticipated mechanical loads by suitable ducting.
As a general rule, attention must be given, in the case of appliance cords (flexible cables), to sufficient pull relief of the cables in the connector(s). It may sometimes be expedient not to screw in the connectors. In the case of tensile load, only plug-in connections, and not the connector/cable or connector/device soldering points will be torn apart.
Underground car parks pose a major problem as regards damage-minimising routing of cables. Due to the fail-safe circuits and long hours during which entrance gates are open, access by outsiders to underground car parks can never be ruled out. The normally low height of the ceilings means it is possible to gain access to the lines located there using only simple tools. When lines are located in the driving area, the space left may be less than the permissible height of vehicles. In that case it is possible for ducts and cables to be damaged or destroyed by vehicles.
When buildings are shared with third parties, steps must be taken to ensure that cables are not run in floor ducts in areas occupied by those parties. Floor and window-sill duct systems must be firmly sealed against the areas of external users, using mechanical means. It is better to confine such ducts to the user's own area.
Areas with a high fire hazard must be avoided. If this is not possible and all cables run on a cable route are to be maintained in a serviceable condition, fire sealing must be provided for that route. If it is only essential that certain cables are kept serviceable, an appropriate cable must be selected for this purpose.
In production plants, high inductive loads and the resultant interference fields are to be expected. These must also be taken account of in the layout of ducts and cables. For cable protection, an approach similar to that of fire sealing is to be taken.
In the case of underground lines, warning tapes must be laid approx. 10 cm above the line. For individual cables (without conduit), it is advisable to provide cable covers.
Cables must be run in such a way that they cannot be moved during a gale. For example, care should be taken to ensure that any cables that run across exposed roof tops are fastened appropriately at least every 5 m. It should be noted here that during a storm powerful forces can act on the cable or cable sections. Moreover, cables must be protected against possible mechanical damage resulting from objects falling on them. Cables run on roof tops or in areas that have lamellar walls should therefore always be laid in protective sleeves.
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by Bundesamt für Sicherheit in der Informationstechnik |
last update: July 2001 |