1.0. Scope
This methodology and safety document "Method Statement For Installation Of Earthing System" uploaded by QHSE Documents highlights the details of the method of installation of the Earthing System.
2.0. Material
2.1. Material used for the installation of the earthing system is as per British Standards: 7671 and British Standards: 7430.
3.0. Applicable Locations
3.1. Basement, Ground level, roof, Mechanical, and Electrical rooms at all levels.
3.2. All mechanical services exposed will be bonded to the earthing system, all extraneous metal below 2.5 Meters shall be bonded.
3.3. Ceiling grids and other such metals & systems shall be measured to assess whether bonding may be required.
4.0. Method
4.1. Storage
4.1.1. All materials received at the worksite/project shall be observed and inspected carefully and closely by the Quality Assurance Engineer and ensured that the materials are as per approved material submittal/shop drawings.
4.1.2. Any discrepancies, damages, etc. shall be reported for further proper action.
4.1.3. Material found not suitable for the project to be removed from the site immediately.
4.1.4. Earthing material shall be stored in a covered/dry place at all times to avoid corrosion.
4.2. Installation of LV Earthing System times
4.2.1. As per approved shop drawings, accurately identify and mark the location of earth pits.
4.2.2. Co-ordinate with the the Main Contractor for installation of earth pits with approved fixing details
4.2.3. The copper earth rod will be driven manually into the earth. After gaining a minimum depth of approx. 3 meters, the earth resistance will be measured accordingly. If the Earth Resistance Value (ERV) is not as per the expectations, the process and work of adding further earth electrodes shall be continued till desired resistance value of less than 1 ohm is gained.
4.2.4. Adjacent earth electrodes shall be spread to at least 1 length of one of the driven electrodes (6 meters) to achieve a result of less than 1 ohm. Work Inspection Request (WIR) to be released.
4.2.5. The earth pit shall be installed after completion of the installation of earth rods and a clear gap of 50 mm shall be maintained between the top of the earth electrode and earth pit cover.
4.2.6. The top of the earth pit shall be properly level with the finished floor level in the area. Earth rods (electrode) connection to be protected with Denso tape securely and appropriately.
4.2.7. The PVC sheathed single core earthing cables of specified size as per shop drawings shall be laid between the earth pit and the earth bar inside the building and terminated with proper type lugs/clamps.
4.2.8. The interconnection of the earth pit shall be as per the approved shop drawing.
4.2.9. All earthing connections shall be made after cleaning the surfaces thoroughly and tightness checks for each connection shall be performed.
4.2.10. Continuity of earth connections shall be checked for every link in the network by the ETA QA Engineer. Issue WIR. All joints to rods to have shrink-wrap protection applied.
4.2.11. The downstream earthing connections from earth bars shall be made to the panel boards, frames, and other equipment as per approved shop drawings.
4.2.12. Along with all power cables on earth cable of size as per approved shop drawings shall be laid and it shall be terminated to the earth bar of the panel and or equipment, which it feeds to, additionally with local earthing from the earth bar.
4.2.13. On completion of the total earthing system and testing, WIR will be submitted for approval to the Design Consultant.
4.2.14. The extent of bonding requirements to be identified and agreed between R&P and MACE in line with project specifications, DEWA standards, statutory requirements & clause 3.0 above.
5.0. Installation of Equipotential Bonding
5.1. The metallic frame of all electrical equipment shall be connected to the nearest earth bar with a specified size of earth cable.
5.2. The earthing continuity of cable trays and trunking shall be maintained with earth links on each joint of cable trays and trunking shall be connected to the earth bar with the specified size of earth cable.
5.3. Flexible earth cable spiral shall be used for the earthing connections when there is the possibility of expansion/contraction and also where vibrating equipment is installed.
5.4. The metallic water lines shall be bonded by an earthing cable of size not less than 6mm2
5.5. All bonding connections shall be carefully and accurately checked and examined for correct tightness and cleanliness.
5.6. WIR will be issued for signature to the Consultant.
6.0. Safety
6.1. All safety measures shall be practiced as per the established project safety plan and procedure.
7.0. Records
7.1. Inspection request duly signed off by Consultant.
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