what is the graphite coating & Why it is used for power cables ?

Graphite is generally used as a conductive coating to enable a sheath test in the field or on the drum, where the cable may not be in contact with an earth medium (eg in conduits, or direct laid in non conductive trenches, or maybe sitting in insulated cable racks in tunnels). It gives it a continuous potential for the sheath test so the whole of the sheath insulation can be tested for damage during installation

One point cable junction

Cable reels specifications (part 2)

• When lifting cable reels by crane, a steel shaft of proper length and diameter shall be placed through the reel drum spindle. The steel shaft shall be threaded at both ends and provided with circular plates and retaining nuts to prevent the reel from falling in case of accidental tilt during the lifting process
• When rolling a cable reel from one location to another, care shall be taken to remove any objects on the surface area that might contact the cable surface. The marked rolling direction must be followed to prevent the cable layers from becoming loose
• The cable storage site shall be an elevated flat surface and must not be reached by flood or sea water
• Reels shall be stored on a solid support or hard and regular surface that will not allow the flanges to sink into the earth.
• Storage areas shall be free of construction equipment, flying or falling objects, chemical or petroleum spill or sprays, open fires or other heat sources and far from heavy vibration areas.
• The conductor or ground wire in reel shall be protected by wood lagging to prevent damage. The conductor reels are set or stored on ground blocking. It is advisable to store the different types of conductors in separate locations. Blocking shall be used to prevent movement or rolling of reels. When the conductor or ground wire is not protected by wood lagging, in no case, shall the blocking touch the conductors or ground wire.

Source SEC standard

SEE previous article 

cable reels specifications (part 1)

·         Cable reels shall be stored and maintained in a proper manner. Cable reels shall be shipped with adequate physical protection to ensure that they can be stored in an outdoor environment for the period of time between arrival and installation

·         All shipping reels for LPOF, EHV & HV cables shall be made of steel. Reels for MV cables Shall be made of steel or wood. Steel strapped wooden lagging is required in all cases. The LPOF cable reels will include a shipping/storage oil pressurization system for the testing and maintaining of proper oil pressure on the stored cable.

·         LPOF cables, when prepared for shipment shall be subjected to expulsion test to check the entrapped gas as per AEIC CS4. Figure 02-06 shows the expulsion test panel

·         When the LPOF cables are completed and ready for shipment, samples of oil shall be taken from each length of cable as per AEIC CS4 to determine the dielectric strength of oil samples.

·         The selection and use of the proper equipment and tools used in cable reel handling is essential. A thorough knowledge of the capabilities of equipment, cable reels weight and physical dimensions are required prior to moving or loading the cable reels

·         For XLPE cables in reels, the inner end and the outer end shall be sealed with heat shrinkable end cap after attaching a pulling eye to the conductor. This sealing method will prevent ingress of moisture into the cable.

·         Care on reel deterioration should be taken if cable are to be stored for extended period. Wooden reels shall be stored on concrete base or on raised wooden stringers placed under the reel flanges.

·         Cable reels shall be stored in an upright position only. Laying cable reelson their flat sides are not allowed.

To be continued

Source : SEC standards