Tuesday, July 11, 2017
METHOD STATEMENT FOR GROUNDING SYSTEM !!
TABLE OF CONTENTS
This Method Statement identifies the work general steps, and the installation requirement of grounding works including ground rod installation, exothermic welding, grounding connection, ground resistance test and inspection to be done at -------project according to approved construction drawings and specifications.
1) SAES-P-111 GROUNDING
2) SAES-P-104 WIRING METHOD AND MATERIALS
3) IEEE – 142 GROUNDING OF INDUSTRIAL AND COMMERCIAL POWER SYSTEM
4) ANSI/IEEE - 142 GROUNDING OF INDUSTRIAL AND COMMERCIAL POWER SYSTEM
5) NFPA - 70 NATIONAL ELECTRICAL CODE
6) SAES-A-114 Excavation and Backfill
a) Electrical Manager / Electrical Engineer
i. Delivering the relevant documentation and the required materials to the Construction Personnel.
ii. Implementation and supervision of the work activities.
iii. Notification after the work completed to Quality Group (Aramco and Contractor). QC Contractor personnel should be informed and verify the work before Saudi Aramco inspector as required.
iv. Taking part in the definition of any corrective actions required ensuring the correct Resolution of the non conformity.
v. Checking the adequacy of subcontractor’s personnel, equipment and promoting any required actions necessary to achieve the construction targets.
b) Electrical Supervisor
i. Lead and plan the work according to the contract drawings and Company standards
c) Quality Control Inspector
i. Inspect the work to comply according to contract drawings and Company standards.
d) Safety Supervisor
i. Make sure that all safety measures are complied before starting the work.
ii. Provide safety instructions to the workers
iii. Hand in hand with the site electrical Supervisor that the work is carried out according to safety controls and procedure.
a) Supervisors and inspector must be eligible and competent for the job.
b) Laborers must able to understand his work and require trade certificates if necessary.
c) Conduct trainings regularly to maintained safety and good workmanship.
a) Cable cutter
b) Set of spanner
c) Metal knockout punch
d) Electric grinder
e) Core drilling machine
f) Welding machine
g) Grounding kits
h) Cad welding kits
i) Cable pulling tools (jacks, winch, cable baskets…)
j) Ground resistance tester
k) Insulation resistance tester
l) Boom truck/crane (when needed)
1) Safety induction shall be done before starting at work site.
2) Tool box talk shall be conducted daily prior to work start.
3) Obtained required work permit before initiate the activities.
4) Proper personnel protective requirement (PPE) including flame resistant clothing (FRC), hard hat, safety shoes, shall be worn when working on or near electrical equipment.
5) SECL safety supervisor shall carry out the safety site inspection to ensure that safety requirement laid in the safe working plan is allowed during and after the work start.
6) Barricading and warning sign must be posted around the working area.
7) Precision tools, hand tools, and special equipment must be calibrated, inspected, periodically and bearing the latest color code before use.
8) Should be provided proper earthing and appropriate rated ELCB for welding machine, generator, compressor etc.
9) All electrical extension cables shall have a proper 6FCi outlet
10) During lifting operation safety pre-caution should be observed.
11) All lifting activity shall have a third party certificate or inspection and color coded, area shall be barricaded during lifting and rigging work.
12) Required wind velocity, as per Luberef standard. If the wind velocity is 32km/h lifting operation must stopped.
13) Construction area fire point wall be established where fire extinguisher, fire blanket stored and keep ready for use, additional fire extinguisher will be provided for immediate work areas during certain phase or work that is particularly susceptible to fire.
14) Emergency procedure shall be communicated to all workmen, availability of first aider / nurse, fire fighter with equipment.
15) Housekeeping shall be conducted on a regular basis to maintained orderly, clean, healthy and safe work place.
a) Tool box talk shall be carried out.
b) If the trench excavation is more than 1.2 meters deep, Confined space entry permit shall be ensured and all confined space entry procedures shall be complied.
c) Ensure all worker assigned are confined space entry trained. Log sheet of personnel entering and exiting the excavation shall be maintained.
d) Ensure the both the edges of trench excavation are properly sloped to allowed entry personnel inside.
e) Ensure sufficient safe access and egress ladder shall be provided and maintained properly.
f) Daily excavation checklist, tanks, and vessels shall be ensured and maintained at all times.
g) Supervisor must be there.
a) Full body harness with two lanyards must be issued for all workers working on 1.8 meters and above and 100% tied off shall be strictly implemented.
b) Samsung work at height training must be completed by the involve workers prior to mobilization to the site.
c) Tools and materials must be secured and tied properly when using and lifting on height respectively
d) Working area should be barricaded.
e) Scaffolding material shall be free of defects, inspected and approved by Samsung.
f) Mobile elevated working platform must be of good running condition, free of defect and with valid third party inspection certificate.
g) Barricading and warning signs must be posted around the working area.
h) All working platform should be inspected and tagged.
1) Grounding cable
2) Cable lug
3) Cable clamp
4) Cable connector
5) Bolts and nuts
7) Ground bar
8) Anchor bolts
9) Grounding rod
10) Shrinkable tube
11) Contact grease
12) Exothermic materials
13) Copper tape
14) Ground cable
a) General requirements: ensure that installation will be carried out in accordance to approved project drawing and specification; the following shall be verified and studied upon execution of grounding.
i. Released and approval of construction drawing will be verified
ii. Verify location of area where grounding works will be executed
iii. Conduit size and lay-out verification (as per drawing schedule)
iv. Grounding cable size, route and length
v. Types of connection which will be made
vi. Stop-up locations
vii. Grounding rod location
b) Survey route and location of installation in reference to construction drawing prior to installation, any obstruction/variations found during survey shall be reported and an alternate route shall be sought from contractor through technical query, items written in the above paragraph (par. A) will be considering during survey.
c) Grounding cable installation and cable pulling
i. Prepare materials and tools for grounding cable pulling; ground cable may be pulled along with any other cable, grouped in accordance to cable schedule.
ii. Verify the location of cable pulling activity where to place the cable drum
iii. Preparation of cable reel for pulling
a. Carefully place the cable in spool stand , ensure that cable drum will not dropped
b. When cable reel needs to be rolled, roll drum in accordance to manufacturers’ roll direction, reel shall be not be rolled in sharp edges, should be rolled on hard surface and avoid sinking to soil when handling.
c. Lifting equipment, tools, rope, slings, men, and soil must not contact the cable or cable protective covering during shipping and handling, and DO NOT apply mechanical force or pressure to the cable surface during handling.
d. Cable will be pulled manually; an adequate number of manpower will be used when pulling longer cable.
e. Check interconnection drawing subject for termite welding.
a) Verify number of grounds for exothermic weld connection.
b) Ensure that mould to be used is correct for the conductor size and application, do not modify mould.
c) Mould to be used may absorb moisture, propane torch may be used to dry out the mould on both side thoroughly.
d) Dry up the conductors for connections, use wire brush to prepare the conductors surface. Scrape the outer surface to remove dirt and oxidation.
e) Insert the conductors and position them for the connection. Close the clamp tightly after connections
f) Insert the steel disk on the mould and ensure that it is properly seated.
g) Take a tube of properly sized welding material and quickly pour into the mould.
h) The bottom of the tube contains compressed material. Tap the bottom of the tube to loosen this material.
i) Pour of this compressed material over the welding material in the mould crucible.
j) Close the lid and pour the remaining 75% of the compressed material into the slot of the mould cover.
k) Aim the flint igniter from the side. Ignite the material on the mould cover and quickly withdraw the igniter to prevent fouling.
l) Allow approximately 30 seconds for completion of the reaction and solidification of the molten material.
m) After removing mould, joints shall be cooled down. Clean joint with soft bristle then apply corrosion inhibitors or protective epoxy compound suitable for grounding joints corrosion protection. Application of compound may be done after completion of cad welding in each area and as joints cooled down.
n) Check that the number of usage for mould does not exceed the required usage stated by manufacturer. Thermo weld mould can be reused as per manufacturer instructions thus need to recheck for any damage upon using.
a) Check that the rod is free from non-conductive coatings such as paint or enamel prior to being driven to the ground.
b) Length of the rod shall have a minimum length of 2.4 meters. Jointed rods are permitted but each joint must be at least 2.4 meters long.
c) The ground rods shall then be brought to their marked location. Clear the area from debris and perform excavation and drilling of earth for rod installation.
d) Set up the drilling machine (core drill will be used as applicable) in place carefully and drill thru the marked location to the maximum depth of the drill bits prepared. then position the ground rod in the drilled hole
e) Insert the fabricated pipe driver from the top of the ground rod and pile drive the rod into the drilled hole. When ample length of the rod has been driven into the earth, manual hammering of the rod can be done.
f) Inspection has to be raised to verify and confirm that the installation of the first rod is acceptable.
g) After that, connect the second rod with the coupling and pile drive the second rod in the same manner as the first till the whole length of the rods are into the earth with the required clearances within the ground rod pit.
h) Permanently concealed ground connections are required; make the connections by the exothermic process to form solid metal joints. Make accessible ground connections with listed grounding connectors.
i) The resistance value of each earth rod shall be noted and the total earth rods to be installed until the prescribed resistance value are acceptable.
a) Check mounting details of ground bar (welding or bolting). Ensure that ground bar will be completely installed.
b) Plate will be welded to equipment or structural column as shown on project drawings.
c) Seal stub-ups of cables to be connected to the ground bar or plate.
a) Equipment Grounding :
i. Check that grounding cable pulled for equipment grounding complies with project drawing, cable specification, schedule and lay-out.
ii. Prepare grounding cable for termination crimping cable ends with proper connector or lugs.
iii. Apply insulation tape (green or yellow/green tape) to cable lugs.
iv. Fix ground cable for equipment's provided termination point with screw or bolt as specified.
v. Tighten bolts in accordance with the appropriate torque value as applicable.
b) Cable Tray Bonding :
i. Drill hole at side rail of cable tray from each end of the splice plate
ii. Check bonding jumper to be used for cable tray as per requirement. Properly crimp connectors for bonding jumper or as specified if braided jumper will be used.
iii. Place screw head on inside of cable tray, put jumper on outside the cable tray add flat washer, locknut and tighten.
iv. Bond cable tray to the local ground grid or ground electrode at both end points ensuring that bonding continuity is met throughout all the racks in the system.
c) Conduit Bonding :
i. Prepare cable for bonding by crimping with correct lugs or connectors.
ii. Connect grounding jumper at both end points by bonding to a grounding conductor, a grounded metal enclosure, or to a grounded metal cable tray with approved grounding clamps and conductors connected externally to the conduit.
a) Fences which are within 10 m of an enclosed ground grid or ground loop that is connected to equipment operated at 1000v or greater shall not be PVC coated and shall be grounded at intervals not exceeding 15 m to the ground grid or loop.
b) All fences within 3 meters of a ground grid or ground electrode shall be bonded at the nearest fence posts to the ground grid or ground electrode.
c) Fences that pass under transmission line operating at 69 kV and above shall not be PVC coated and be grounded at intervals not exceeding 15 m.
d) Fences that cross over a ground grid or conductors that connect two ground grids shall not be PVC coated and shall have a bond between the grids or conductors and the nearest post. If the crossing area is extensive, the bond is required every 50 m.
a) All stages of work shall be inspected in accordance with the approved project quality control inspection plan.
b) Inspection / Quality activities shall be as per the corresponding SATIP and SAIC.
c) Fall-Of-Potential Test I Ground Resistivity Test will be done in compliance with IEEE Standard 81 on the main grounding electrode or system.
d) For large ground works, it may be necessary to locate the current and potential electrodes a considerable distance from the connection to the network. In this instance, the current and potential electrodes can be placed at a minimum angle of 90 degrees.
e) In all cases step and touch potentials during ground faults shall not exceed the safe values defined in IEEE 80 (SAES-P-111 Sec. 8.2).