QA&QC Earthing System.docx

7/16/2019 QA&QC Earthing System.docx

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EARTHING SYSTEM INSTALLATION

METHOD STATEMENT

FOR


Rev. No. Details Of Revision Date Prepared by Checked by Approved by




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 qualityinspections and tests.

3. REFERENCES:

The following documents are considered as reference documents:

Project specifications.

Applicable international codes & standards.

Project Quality Plan.

Quality Inspection Plan.

Project drawings.

4. ABBREVIATIONS/DEFINITIONS:

SM Site Manager PQP Project Quality PlanQIP Quality Inspection PlanI/C In -chargeQA&QC Quality Assurance & Quality Control

MS Method StatementPPE Personal Protective EquipmentHSE Health, Safety & EnvironmentIMTE Inspection, Measuring & Test EquipmentBA Business AreaFRM Form

5. RESPONSIBILITIES:

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

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

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

6. PROCEDURE:




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 layoutdrawings.

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 drivenin 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 rigidconnections.

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

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

6.3 Earth Continuity Conductor (ECC)

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

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

hardware.

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

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

6.4 Testing of Earthing System




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

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

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

7. TOOLS AND EQUIPMENTS:

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

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

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

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.

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

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

Spanners and wrenches - Right type and size shall be used. Extension onspanners and wrenches shall not be used unless the wrenches are designedfor such use. A pipe wrench shall not be used as a hammer. A wrench (exceptslugging wrenches) shall not be hammered to tighten a bolt.

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

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

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 bedamaged.

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

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




8. HSE INSTRUCTIONS:

8.1 Existing Installations at live plants

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

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

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

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

A competent qualified electrician shall only carry out installation andmodification work in the vicinity of any electrical equipment under full timesupervision.

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

8.2 New Installations at construction sites

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

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

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

The temporary electrical network installed for the job would be protected by

ELCBs (Earth leak circuit breakers) to avoid any accidental contact. Personal protective equipment must be used as required by safe work

practice

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

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

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

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

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




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

9. RELATED DOCUMENTS:

QA&QC Earthing System.docx

Documents

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