Cable Ducts
Electricity, pilot and telephone cables shall only be installed into electricity cable ducts, complying with UK Power Networks’ Engineering Approval Standard EAS 00-0002.
New cable ducts shall be black in colour and marked with the legend 'Electric Cable Duct' on two diametrically opposite sides.
Cable shall only be installed in ducts that are suitable sized to accommodate them, Appendix A details the minimum internal duct diameters allowable for the most common types of cable used by UK Power Networks.
All cable duct joints shall be installed in accordance with the manufacturers' instructions or recommendations and should be installed in such a way to prevent those damaging cables as they are installed.
All cable ducts and tubes entering substations or buildings shall be sealed with the appropriate RDSS Rayflate® duct seal, as specified in UK Power Networks’ Engineering Approval Standard EAS 00-0002 to prevent the ingress of gas and water, even if the ducts do not contain a cable.
Where reasonably practicable, before a cable is installed, all duct lines shall be checked and cleared of all obstructions. To ensure that the duct is suitable for the type of cable to be installed, a 3 metre length of the cable to be installed shall be pulled through the complete length of duct. This shall then be examined for damage, before any attempt is made to install the complete cable. If the sample of cable is found to have deep scores and tears in its outer sheath, which are more than half the thickness of the outer sheath, the duct route shall be repaired before any attempt is made to install the final length of cable.
33kV, 66kv or 132kV cables; and their associated pilot and telephone cables shall be installed in appropriately sized ducts installed a cement bound sand material, complying with the requirements of ENA TS 97-01, except where cable rating calculations prove that a stabilised backfill material is not required.
Installation of Underground Cables - LV to 132kV Document Number: ECS 02-0019 Version: 10.0 Date: 02/06/2015
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When a thermally stable duct filling material (such as Bentonite) is to be used as specified in Appendix C of ENA TS 09-02, the duct shall be installed in a cement bound sand material, complying with the requirements of ENA TS 97-01, except where cable rating calculations prove that a stabilised backfill material is not required and the joints in the pipe or duct shall be effectively sealed to prevent the migration of the material and preserve it’s moisture content under service conditions.
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