SCOPE AND PURPOSE
This "Method Statement" covers the on site installation and testing of Bus bar Trunking systems with relevant accessories and the requirements of checks to be carried out.
REFERENCE DOCUMENTS
• Project Specifications Volume III, Division 16, Section: 16010, 16050, 16477
• Approved shop drawings (latest revision)
• Approved material submittals
• Manufacturer’s installation instruction
• Local authority regulations (DEWA, CIVIL DEFENCE, etc.)
GENERAL
Bus - bar trunking system generally includes standard straight lengths, special straight lengths (wherever necessary), elbows (vertical and horizontal), offsets, T -joints, standard component tap off boxes, feeder boxes, fixing elements, flanges, support systems and end connections etc; various items of the equipment. Installation of bus ducts will be carried out as per the project specifications and drawings and DEWA regulations.
EQUIPMENT
• Site Engineer/Site supervisor.
• QA/QC Inspectors.
• Physical verification of materials will be carried out for any damages prior to taking from stores and also prior to installation. Manufacturer’s test certificates received will be reviewed and submitted to consultant for approval.
• Prior to commencement of work, area and access will be inspected to confirm that the site is ready to commence the work
• All relevant documentation and material applicable to particular section of works will be checked by site engineer before commencement.
• Physical verification of material will be carried out for any damages prior to taking from stores.
• The site engineer / supervisor will give necessary instruction to tradesman and provide necessary construction / shop drawings.
• The site engineer / supervisor will also check that tools and equipments available are in compliance to contract requirements.
• The site supervisor also explains tradesman regarding safety pre-cautions to be observed.
METHOD OF INSTALLATION
1. Bus bar installation will be carried out as per approved bus bar lay out/isometric drawings. Before starting the installation of bus bar system, proper co ordination shall be done with other trades.
2. Manufacturer’s installation instructions attached will be followed for handling, storage, installations and testing.
3. Determine the position of the bus bar supports as per approved construction drawings and mark them on concrete surfaces.
4. Fix the support as per manufacturer’s installation instructions.
5. Provide sufficient horizontal and vertical clearance from walls and ceilings to provide easy access to joints, both for permanent installation and possible future removal of section when required.
6. For vertical bus bars, ensure that no joints or expansion joints are installed in the slab thickness.
7. Bus bar will be leveled and mounted at the correct height.
8. Elbows, offset and tap off boxes etc., will be installed as per approved construction drawings and as per manufacturer’s instructions.
9. Cable gland plates for tap off boxes and fixing elements shall be installed as per the recommendations of the Manufacturer and as per approved schematics.
10. Cable gland plates for tap off boxes and fixing elements shall be installed as per the recommendations of the Manufacturer and as per approved schematics.
11. Bus bar should be installed so that the orientations of phase from the front side will be GRY&N. The cabling from tap off shall be from side or bottom.
JOINT ASSEMBLY
12. Ensure that all contact surfaces are clean and free of containments.
13. Align the bus bar ends of adjoining sections, verifying proper phase alignment, and slide the sections together (use joints pullers, if required).
14. Expansion joints if required as shown in approved construction drawings will be installed as manufacturer’s instructions attached.
15. After completing the jointing of assemblies, torque the joints bolts to the specific value.
16. Where a bus bar extends through a inside block. Shear walls, an internal transverse barrier supplied by manufacturer will be installed.
17. Bus ways to be properly covered during the installation to protect them from moisture or other types of contaminants.
18. All the floor/wall crossing of bus bars is to sealed with approved type of fire sealant.
19. Bus bar enclosure continuity shall be ensured with proper bounding and connected to the main earthing grid through return paths al LV Panel end.
TESTING
After complete installation of Bus bar systems, Bus bars are subjected to following tests as recommended by Manufacturer:
• Checking of all joint connections for tightness.
• An Insulation Resistance test, carried out with a calibrated Megger insulation tester, to ensure that system is free from short circuits and grounds (ground, phase -to- neutral and phase-to-phase). It should be noted that readings vary inversely with the length of run and width or number of bars per phase.
• Verify that system phasing matches the busway phasing before reconnecting all connections to switchboards.
• Continuity tester will be used to check electrical continuity of SS/QCE phase bus bars, neutral bus bar and earth bus bar.
QUALITY CONTROL
• QCE along with Project Engineer and site Supervisor will monitor that all components are installed as per the contract specifications and approved submittals.
• Inspection Request (IR) shall be submitted to the Main PE/SS/QCE Contractor/Consultant during the following stages :-
• After completion of installation of bus ducts for a particular area/section.
• For testing of Bus ducts.
SAFETY
• Work will commence as per safety regulations laid down in the contract specification and project safety plan.
• Proper safety harness to be used and secured, if required.
• All personal protective equipment shall be used as appropriate according to the nature of job.
• Housekeeping shall be of good standard and all cut lengths and debris shall be removed.