QA&QC Earthing System.docx

EARTHING SYSTEM INSTALLATION

METHOD STATEMENT FOR EARTHING SYSTEM INSTALLATION

Rev. No.

Details Of Revision

Date

Prepared by

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Approved by

EARTHING SYSTEM INSTALLATION

1.

OBJECTIVE: The objective of this method statement is to provide guidelines for inspection of the earthing system installation.

2.

SCOPE: This method statement covers the activity of earthing system installation for quality inspections and tests.

3.

REFERENCES: The following documents are considered as reference documents:     

4.

Project specifications. Applicable international codes & standards. Project Quality Plan. Quality Inspection Plan. Project drawings.

ABBREVIATIONS/DEFINITIONS: SM PQP QIP I/C QA&QC MS PPE HSE IMTE BA FRM

5.

6.

Site Manager Project Quality Plan Quality Inspection Plan In -charge Quality Assurance & Quality Control Method Statement Personal Protective Equipment Health, Safety & Environment Inspection, Measuring & Test Equipment Business Area Form

RESPONSIBILITIES: 

Area incharge E&I checks earthing system layout and typical installation drawings for the activity.

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Area supervisor E&I checks earthing resistance at the test points, after complete installation at site and record the values on FRM (refer to related documents).

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The quality inspector checks that the relevant work is being carried out in conformance with project specifications, PQP and QIP along with the best engineering practices. In case of non-conformance at any stage, it will be controlled by corrective action request. If an inspection plan is given by customer, the sequence of inspections will be followed accordingly.

PROCEDURE:

EARTHING SYSTEM INSTALLATION

Following checks should be performed for the installation of earthing system, in accordance with project specifications and reference documents. 6.1

Earth Electrodes 

Earth electrode locations are to be checked to conform to earthing layout drawings.

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Checks should be performed for the installation of earthing system for following a) Size and quality of electrode/ plate. b) Quantity & quality of coal - salt-lime stone mixture. c) Dimensions of earth pit. d) Connection of earth continuity conductors to the electrodes/ plates and earthing bar. e) Earth electrode inspection pit.



Rod electrodes are to be checked for size, quality and the length driven in ground, couplings & terminal connections.

6.2

Earthing Mesh 

All earth electrodes are to be inter-connected according to layout drawings. Inter connecting conductors are to be checked for proper size and rigid connections.

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At all bolted joints, corrosion resistant grease is to be used as specified.

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Thermo weld jointing is to be checked for complete fusion of jointed conductors depending on project requirements. Thermo weld cartridges & moulds are to be of approved quality and proper size.

6.3

6.4

Earth Continuity Conductor (ECC) 

All earth continuity conductors are to be checked for specified sizes & types.

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ECC connected to non - copper metallic points are to be tinned using proper hardware.

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Splicing & tapping of ECC is to be done either with compression connector or thermo welds, depending on project requirements

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Splicing & tapping of strip type ECC is to be done with bolts or rivets of specified material.

Testing of Earthing System

EARTHING SYSTEM INSTALLATION

7.



All earth electrodes are to be tested individually for earth resistance, which is to be properly recorded on FRM Earth resistance value above a specified minimum is to be improved as per specifications.

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Earth electrodes are to be interconnected to get the overall resistance of the earthing mesh as per specification.

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It will be preferable that inspection/testing of earthing system should be carried out through checklist

TOOLS AND EQUIPMENTS: 

Correct type, size and weight of tool shall be used for each job.

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Properly insulated and non-conductive tools shall be used for electrical work.

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Proper compression type tool such as lugs press should be used for compression type connections.

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Screwdrivers - A screwdriver shall have the correct size of tip to fit the slot of the screw. Screwdrivers shall not be hammered or twisted with pliers or wrenches. Screwdrivers shall not be carried in the pockets.

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Hammers - Right kind of hammer shall be selected for the job. Eye protection shall be worn when hammering.

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Picks and shovels shall be maintained in a serviceable condition. Shovel blades shall not be allowed to become blunt, turned, split, or jagged, Pick head points shall be kept sharp and heat-treated so that the metal wears down in use and does not splinter or chip off. Shafts of picks and shovels shall be kept free from cracks and splinters.

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Spanners and wrenches - Right type and size shall be used. Extension on spanners and wrenches shall not be used unless the wrenches are designed for such use. A pipe wrench shall not be used as a hammer. A wrench (except slugging wrenches) shall not be hammered to tighten a bolt.

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Pliers shall not be used as wrenches. It will be ensured that scrap does not fly off and cause injury when cutting metal with pliers. Only long handled pliers shall be used to cut wire under tension. Pliers with insulated handles shall be used for electrical work.

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Hacksaws - Correct type of blade shall be selected to suit the material to be cut. The blade should be set in a hacksaw frame so that the teeth are pointing in the forward direction and sufficient tension shall be applied to ensure the blade is maintained rigid.

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Power tools - All portable power tools shall be stored in clean dry conditions. Power tools shall not be left lying around the job site where they may be damaged.

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Rotating tools shall be switched off and held until rotation has completely stopped before they are set down. Tools shall be disconnected before changing bits, blades, cutters, or wheels.

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All portable power tools shall be equipped with properly functioning "dead man switches".

EARTHING SYSTEM INSTALLATION

8.

HSE INSTRUCTIONS: 8.1 Existing Installations at live plants 

All efforts should be made to keep the environment clean. Any liquid fuel spills and accidental waste disposal should be avoided and properly cleaned up.

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No trash, papers, polythene bags, rappers, cans, bottles or any other litter should be left in the open trenches.

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No one shall be allowed to interfere with work in the immediate vicinity of any existing electrical installations or equipment without a valid permit to work. This applies to both temporary and permanent electrical installations and equipment.

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Where it would be required to work in the vicinity of electrical equipment, all necessary precautions to avoid accidental contact with live conductors, etc, would be taken.

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A competent qualified electrician shall only carry out installation and modification work in the vicinity of any electrical equipment under full time supervision.

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Only persons under full time supervision by a competent qualified electrician shall be permitted inside substations, unless with written permission from the customer’s representative.

8.2 New Installations at construction sites 

Material or equipment should be maintained in an orderly manner and labeled in accordance with statutory requirements and use in safe manner.



The electrical supply to powered hand tools shall not exceed 24 volts. Where this is not possible, due to the type of tool being used, the approval of the customer’s representative must be sought. But these electrical supplies must be protected by ELCBs (Earth leak circuit breakers).

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Electrical lighting for use in confined spaces shall not exceed 24 volts. Powered hand tools used in confined spaces shall, be air operated. Where this is not possible, all such tools shall be equipped with a deadman’s switch.

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The temporary electrical network installed for the job would be protected by ELCBs (Earth leak circuit breakers) to avoid any accidental contact.

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Personal protective equipment must be used as required by safe work practice

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For excavation in rocky area while using jackhammer, ear protection shall be provided.

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Unfilled excavated trenches must be provided with warning lights during night.

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Persons shall be provided hand protection (gloves) while pulling earthing cables manually.

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Earthing cables in open trenches shall be protected from welding sparks and other falling objects by using G.I sheets etc.

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Signs shall be posted after back filling of cable trenches showing “ELECT CABLE UNDER GROUND”.

EARTHING SYSTEM INSTALLATION 

9.

Earthing cable scrap shall be removed on daily basis from panels/control rooms.

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