INSTALLATION OF EARTHING AND LIGHTNING SYSTEM

INSTALLATION OF EARTHING AND LIGHTNING SYSTEM

General Requirement:

  • All material received at site shall be handled and stored upon receipt in accordance with Project Procedure for Material Control.
  • Installation shall be conducted by the Electrical Supervisors and inspected by Electrical QC Inspector.
  • Equipment using for testing should have valid calibration certificate.

 Installation of Earthing cables

  1. Earthing cable route shall be as per IFC drawings to ensure proper size location, correct routing, tagging & installation.
  2. For Underground cable, size and depth of cable trench shall be installed as per typical earthing installation details.
  3. Cables forming part of the main earth grid will be laid in trenches and trays in accordance with the project specifications. Underground joints branch connector shall ensure good mechanical and electrical bonding.
  4. Branch connector shall be checked to ensure good mechanical and electrical bonding for termination.

Installation of the Earthing Rod, Inspection Pit & Cover

Earth rod locations and installation shall be checked against the detail drawings to ensure correct positioning.  Where rods are to be “hand driven”, the procedure shall ensure the correct depth.  Where rods are to be installed in pre-drilled bore-hole, the bore-hole reports will be submitted to ensure the correct depth is achieved and the back-fill material is as per specification.  Upon completion, the installation of the earthing rod, earth pit, earth pit cover, and termination it will be checked against the earthing installation detail.

 Installation of Earth bus bar and earth bonding

  1. The location of earth bus bars will be checked against the layout drawings and the assemblies checked to ensure the fixings are secure.
  2. Equipment will be installed to ensure the earth bonding, cables stub-ups; sealing compound and branch connector are installed and located as per the layout and detailed drawings.
  3. The termination of the earth cables will be checked to ensure the crimping or bolting is secured.
  4. As per company response the reinforcing bars need not be connected to the earthing grid since electrical equipment have an appropriately sized ground wire connected to ground well that positively grounds the electrical equipment.

Installation of Lightning Protection

  1. The Lightning Protection shall be checked against the layout and detailed drawings.
  2. Earth tapes and down conductors shall be installed as per specification, installed as per the detailed drawing and securely clipped. Cross jointing, clamping and bonding will be checked for tightness and electrical continuity.
  3. Test clamps will be installed to ensure that it is securely fixed as per the installation detail and disconnect facilities is operable.
  4. Bonding of associated metal structures will be visually checked against the layout drawings.

Testing Procedure

The test method shall be conducted for minimum requirements for all facilities before backfilling of the trenches applied as follows:

Testing for Earthing System

  1. Measurement of earthing resistance of each electrode.
  2. Check continuity of equipotential loop, protection conductors and generally all earthing and bonding conductors.
  3. Measurement of earthing resistance of the grid network.
  4. The earth resistance minimum acceptable value shall be:
  • Non-Hazardous Area – Less than 10 ohms
  • Hazardous Areas – Less than 1 ohm
  • Dirty & Signal earth – Less than 1 ohm

The test shall be conducted by Site Electrical Engineer/Supervisor, witnessed and recorded by the Electrical QC Inspector.

Testing of Lightning Protection System

The resistance of each earth electrode will be checked to ensure that the resistance value of each electrode group does not exceed 10 Ohms.

FIELD INSTALLATION CHECKLIST FOR EARTHING & LIGHTNING

  ITEMS TO CHECK COMPLIANCE (YES OR NO)
1. EARTHING CONDUCTOR TYPE & CORRECT SIZE.
2. EARTH ROD TYPE & CORRECT SIZE.
3. EARTHING CONDUCTOR BURIAL DEPTH AS PER SPECIFICATION.
4. EARTHING AND LIGHTNING JOINT CONNECTION LOCATION.
5. LOCATION OF EARTHING AND LIGHTNING POINTS.
6. TIGHTNESS OF JOINT CONNECTION.
   7. LIGHTNING AND EARTHING SYSTEM FOR BUILDING AND EQUIPMENT AS PER  SPECIFICATION.
8. EARTHING RELAY DEVICE AND INSULATION CHECKING DEVICE SETTINGS VERIFIED AND OPERATES PROPERLY.
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