Method for Installation of Cable & Wire (Part-1)

Purpose:

  • The method explains the Procedures or activity for safely installation and Testing of MV cable in directly buries in ground, in trenches, in to cable trays or in underground ducts as per the standard Practice and Code.

General Equipment & Tools:

  • Testing Equipment for Cable
  • LV / HV Insulation Resistance tester (250V to 5KV)
  • Multi-meter
  • Continuity Tester
  • AC High Voltage Test Kit

Storage & Material Handling:

  • The storage area must be free from dust and Water leakages / seepages.
  • Manufacturer recommendation shall always be followed in loading/unloading and storing of Material.
  • Material and its accessories shall be unloaded handle with care in designated area of the Store (Do not directly drop to Ground) to avoid any damages.
  • Materials shall be stored in a dry place which is free from water or from weather effects and protection should be given to the material by means of covering the material with Tarpaulin sheet.
  • The Material will be stacked / unload in the site store on a proper stand on wooden loft on a flat surface at a sufficient height from Ground.
  • If Material are dispatch in packs or pallets, each pack or pallet shall be lifted individually with suitable lifting equipment.
  • The material shall be transported / Shifted in their original packing to Site location.
  • The cable drums shall be off-loaded at the site locations.

  • The cable drum should be visually inspected for damage, which may have occurred during transport.
  • During storage periodical rolling of drums once in 3 months done. Rolling shall be done in the direction of the arrow marked on the drum.
  • It should be ensured that both ends of the cable are properly sealed to prevent ingress/absorption of moisture by the insulation.
  • Protection from rain and sun shall be ensured. Sufficient ventilation between cable drums, should be ensured during storage.
  • The drums shall always be rested on the flanges and not on the flat sides. f. Damaged battens of drums etc. should be replaced, if necessary.
  • When cable drums have to be moved over short distances, they should be rolled in the direction of the arrow, marked on the drum
  • While transferring cable from one drum to another, the barrel of the new drum shall have a diameter not less than that of the original drum.
  • The manufacturer’s seal on the inner and outer cable ends should be examined and the condition of the sheath inspected for mechanical damage.
  • If the cable is found defective it shall not be installed and the cable shall be returned to the supplier for replacement.

Inspection of Materials:

  • Check The Material according to its Type, Size, Make
  • Inspection of Cable:
  • Type of Cable (HT /MV /LV)
  • Cable Operating Voltage
  • No of Cable Core (1 core,2core,3 core, 3.5 Core,4 core)
  • Type of Cable Core (Cu, Alu)
  • Type of Cable Material (PVC,XLPE)
  • Size of Cable
  • Length of Cable
  • Physical Damages Inspection:
  • Damage on Cable Drum
  • Damage on insulation of Cable
  • In case of any damages observed during inspection, the concern report will be issued and Material shall be returned to the supplier for replacement.

Testing and of Cable:

(1) Insulation resistance test:

  • Following Insulation resistance test will be carried out by approved calibrated equipment.
  • At the Time of Cable drum receiving at the Store
  • Before Installation of Cable on Site.
  • After Installation of Cable on Site.
  • The Insulation Resistance values will be noted for Core to Core and Armor by DC High Voltage Tester (Megger) before following activities.
                                    Voltage Class Test instrument Acceptance Value
L/V Cable 1000 VDC >20 Mega ohm
M/V Cable 5000 VDC >100 Mega ohm
Control, Instrumentation, Communication cable 250 VDC >1 Mega ohm
  • The cables and conductors must discharged after Insulation Resistnce test.

(2) The continuity test:

  • The continuity test would be carried out between
  • Phase to Phase,
  • Phase to Neutral,
  • Phase to earth and
  • Neutral to Earth.
  • The results would be recorded for records and future reference.
  • After the test, the end of the cable shall be sealed to prevent the ingress of moisture.

General Steps for Cabling Laying

  • Shifting of Cable Drum at Working Location:
  • If a crane is used to unload / Shift cable, a shaft through the arbor hole or a cradle supporting both reel flanges should be used.
  • Forklifts must lift the reel by contacting both flanges.
  • Check and ensure that approved drawings, the correct size and type of Cable & accessories are ready for installation.
  • Ensure that Cable and accessories received from site store for the installation are free of rusty parts and damages.
  • Installation of Cable Drum on Jacks:
  • Check and ensure that the Correct Size and Type of Cable Drum and accessories are transported at the Site locations.
  • Ensure that cable and its accessories received from site store for the installation are free from rust, corrosion and damages
  • Location of cable drum should be planned before transportation of cable drum. (Practically could differ at one or two places for easy installation of cable).
  • The cable drums shall be un-packed.
  • Depending on the weight and size of the drum, suitable size of the cable spindle shall be placed inside the central axis of the drum.
  • Suitable jacks shall be placed firmly on the ground and jacked-up the Drum to allow sufficient clearance from the ground. Ensure that the cable drum on a jack is free for rotation.
  • The cable drum will be correctly positioned and the direction of cable pulling as indicated by arrow on the drum shall be complied.
  • Drum control during pulling
  • Cable winch, if required, shall be positioned in proper place for cable pulling.
  • The cable shall be fixed to the winch, if used, by means of a cable sock or gripper. Required number of persons will be posted at winch and near the drum.
  • At all times during the pulling operation, at least one member of the team shall be stationed at the drum to control its rotation and check on the stability of the drum and jacks.
  • Cable Roller:
  • Cable rollers shall be placed as required on the cable route.
  • Cable rollers will be placed not more than more than 3 meters apart under the M.V cable during pulling over longer distances and standoff rollers for acute bends to ensure that the cable is pulled with minimum effort and the cable outer jacket is free of scouring lines.
  • Cable Pulling Speed:
  • The required cable pulling speed and tension requirement shall be maintained according to the manufacturer’s specification. If any problem arises during the pulling, the proceedings shall be stopped immediately and restarted only after the problem has been cleared.
  • The pulling speed shall be controlled during the cable pulling and it will be assured by observing the indication of the tension meter.
  • Cable pulling shall be done under strict supervision during the entire period of operation. Safety norms shall be observed and shall stick to the standard requirements
  • Identify Cable Laying Route:
  • Location of the panels / equipment shall be identified.
  • Cable laying will generally start from one end of the route length or at any suitable point if required.
  • In case of cable lengths which are more than one drum length, all cables which can be laid from original position will be completed. And then the cable pulling set-up will be re-positioned to the next location, from where the next length will be pulled.
  • Cables shall be cut from the drums as per the actual cable length in accordance to the drum schedule and drum allocation sheets
  • Before cutting the cable, both ends must be inspected to ensure sufficient length is for proper dressing and end termination.
  • The cable schedule and drum schedule will be updated with the information on cable pulling.
  • Cable rollers shall be positioned properly in to the cable trench. The intervals for the rollers are to be kept approximately 2 to 3 meters.
  • The rollers shall be maintaining its smooth rotation. If the cable will run through the curves and edges the, curve rollers should be used at the proper position in order to keeps a safe cable bending.
  • Precaution while laying of Cable:
  • Where bends are encountered in a run, cables shall be lubricated with a cable pulling lubricant (without Petroleum based) to facilitate easy movement.
  • Ensure excessive force and twisting of cables is avoided
  • Proper spacing will be maintained between the cables
  • Cables are protected from mechanical damage during pulling
  • Protection shall be provided to the cables at crossings with pipes, civil works to prevent mechanical damage.
  • PVC sleeves shall be installed for all cables passing through brick, block or concrete or similar structures in case there is need for future withdrawal.
  • After the Insulation Resistance Test, the open ends of the cable will be sealed till termination to prevent entry of Moisture and water.
  • After completion of all cables in the same route the cables shall be dressed and clamped.
  • Unless the lengths exceed the maximum drum lengths joints shall be avoided. Joint markers indicating joint positions shall be provided above ground and also shown on the drawings.
  • Empty cable drums will be transported back to stores.
  • Measure Insulation Resistance before Laying Cable
  • Insulation resistance of the cables shall be checked before laying cables.
  • Measure Insulation Resistance After Laying Cable
  • Soon after completion of every cable laying the cables will be tested for insulation resistance.
  • Cable Bending Radius:
  • During installation process cable can not be bent to a radius of less than 6D for unarmored cable and 8D for armored cable or bending radius of cables shall comply with cable manufacturer’s recommendation. These conditions shall be strictly follow to, particularly where cables turn into road crossings, conduit entry etc
  • Eliminate Sharp Edge:
  • While pulling, in order to eliminate sharp bend and crossovers, always have a person feed the cable(s) straight into the conduit by hand or, for larger cables, over a large diameter sheave.

  • Do not pull cable directly across short, sharp angles. After pulling completely out of one side of the enclosure, feed cable into the other side of the enclose and pull that segment.

  • Cable Laying Arrangements:

  • The configuration of three single-conductor cables in a conduit is determined by the ratio of the conduit inner diameter (D) to the outer diameter (d) of one of the single cables (D/d ratio).

  • A cradled configuration develops when three single-conductor cables are pulled into a conduit where the D/d ratio is 2.5 or greater.
  • A triangular configuration develops when three single conductor cables are pulled into a conduit where the D/d ratio is less than 2.5.
  • These cables may be pulled from individual reels, tandem reels, or a single reel with parallel wound cables.

About Jignesh.Parmar (B.E,Mtech,MIE,FIE,CEng)
Jignesh Parmar has completed M.Tech (Power System Control), B.E(Electrical). He is member of Institution of Engineers (MIE) and CEng,India. Membership No:M-1473586.He has more than 16 years experience in Transmission -Distribution-Electrical Energy theft detection-Electrical Maintenance-Electrical Projects (Planning-Designing-Technical Review-coordination -Execution). He is Presently associate with one of the leading business group as a Deputy Manager at Ahmedabad,India. He has published numbers of Technical Articles in “Electrical Mirror”, “Electrical India”, “Lighting India”,”Smart Energy”, “Industrial Electrix”(Australian Power Publications) Magazines. He is Freelancer Programmer of Advance Excel and design useful Excel base Electrical Programs as per IS, NEC, IEC,IEEE codes. He is Technical Blogger and Familiar with English, Hindi, Gujarati, French languages. He wants to Share his experience & Knowledge and help technical enthusiasts to find suitable solutions and updating themselves on various Engineering Topics.

2 Responses to Method for Installation of Cable & Wire (Part-1)

  1. zsiddiki says:

    Very informative and knowledgeful article , very much suited for young supervisors and trainee Engineers.

  2. mohammad khan says:

    Dear Jignesh Thanks for your email along with Electrical Notes..Please keep up this service to humanity.It has greatly increased my knowledge of the subject Regards M.M.KHAN

    Sent from Mail for Windows 10

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