Before starting the installation of power busbar following tools shall be arranged:
- Tower Crane / Fork Lift for transporting Busbar
- Chain Block Pulley (Suitable Capacity)
- Portable hand tolls
- Portable Drilling Machine
- Spirit Level (1,50 meter – 2,00 meters long)
- Level Threads
- Torque wrench (capacity recommended by manufacturer)
- 1000 volts Megger
Installation Procedure for Power Busbar:
PREPARATION FOR INSTALLATION
Start of Busbars installation shall be done in accordance with approved shop drawings and properly coordinated with Site Engineer’s for the exact locations and levels. The mark on site to be carried out prior to commencement of installation works.
Electrical Engineer or Electrical Supervisor should check the approved isometric drawing of Busbar layout and ensure that all sections of the Busbars are received at site.
During shifting to installation location, lift busbar and its associated fittings using proper lifting equipment or manually with adequate number of people. Never drag the busbars across the ground, handle with care to avoid damage to internal components and the enclosures. All involved personnel will wear appropriate personnel protection at all times during the entire period of unloading/shifting.
If the busbar is not yet installed, store busbar and its associated fitting in a clean and dry area to prevent condensation. Do not allow the busbar to contact with corrosive fumes, liquids and other foreign matters. It must be stored off the ground and securely covered to provide protection from dirt & moisture. Busbar should not be stored outdoors without proper weather protection.
Prior to installation, ensure that approved shop drawings for construction details of bus duct arrangement & bus duct routing is available as approved by the supervision consultant. This drawing should be followed carefully to ensure proper busbar system.
- In shafts, Busbar riser works are carried out over temporary working platforms which are installed at every floor level.
- Separate safety / emergency rescue plan with procedures is attached.
- Site Supervisor/ Safety Supervisor to check proper lighting and ventilation availability before starting of any works.
- Ladders / scaffoldings to be secured firmly over the working platform and checked by competent scaffolding inspector, prior to start of work.
- Site Supervisors to keep check of working technicians in risers in regular intervals.
INSTALLATION / WORK SEQUENCE
- Prior to installation ensure all relevant drawings are approved and available to the installation team.
- Installation of bus bar starts from Main distribution board. During the installation. chain block (1-2 tons) will be used to lift the bus bar & its component to its proper position as per the approved drawing. During the installation process workers involved wears appropriate safety protection.
- Distribute pieces of the bus bar and its associated fitting to each floor as per the approved drawing details of bus duct arrangement. In shifting the materials to each fioor tower crane I fork iift will be used or manually with adequate number of people. All involved personnel must wear appropriate personnel protection during the entire period.
- Install horizontal busbars & vertical busbar riser including its supports in accordance with the approved specification, manufacturer’s recommendation & approved shop drawing.
- HORIZONTAL MOUNTING SUPPORT: Use approved channel l hanger flat & down rod as per manufacturer’s recommendation.
- During the installation maintain good alignment of the drop rods along the busbar run; do not support the busbar at the joints. After the busbar is secured in the hangers, adjust the hangers on the rod for the correct elevation.
- Joint shall be done as per manufacturer’s recommendations; this is to avoid any ingress of moisture into the bus duct system.
- Prior to jointing, both section of bus duct to be joined undergo continuity & insulation resistance test. Joints shall be made by simply sliding together the bus duct unit, and tightening the clamping bolts progressively to the specific torque. Ensure that all joint contact surfaces are free of contamination.
- Install plug in box (MCCB) as per the approved shop drawing and manufacturers recommendation.
- Ensure that during the installation of the plug in box (MCCB) the operating handle shall not be more that 2 meters above finish floor level (FFL).
- VERTICAL MOUNTING SUPPORT. Use vertical support (vertical hanger) & spring support (vertical spring hanger) as per manufacturer’s recommendation. Prior to installation, check the opening in each fioor where the busbar will go through. after the busbar is placed through the floor; the floor fiange must first be installed before installing the vertical hanger. This must be done in conjunction with mounting supports or channel. Ensure that it is capable of absorbing a horizontal movement of 60 mm in any direction. Provide vibration insulation pads.
- Install first outlet of the vertical at a minimum distance of one foot above the floor.
- Install floor flanges at each floor penetration.
- Provide approved fire stop material at floor & wall penetration in accordance with the appropriate standards and requirement of the local authorities
- Provide a minimum of 75 mm high concrete curb around bus duct floor penetrations.
- During the installation, inspect the bus bar run for straightness in all planes and make any adjustment necessary for good alignment.
- Clearance between bus ducts running in vertical riser shall be considered during the installation in order to allow for adequate heat dissipation & for installation of the bus duct selection joint.
- Install expansion joint wherever required in accordance with contract documents, approved shop drawing & manufacturer’s recommendations as well as on every building expansion joint.
- After the erection, use vinyl or corrugated cardboard or with polythene sheets to cover the Power Busbar System, protection for concrete, plaster and water damage etc.
- Any missing tools or equipments shall be provided for perfect installation.
- Ensure A danger notice is fitted to all accessible panels where a voltage exceeding 200V and the Power Busbar System is protected until the building is clean, and system is ready to be energized.
CONTINUITY TESTING OF POWER BUSBAR
- Prior to installation of Power Busbar System and before electrical circuitry has been energized, demonstrate product capability and compliance with requirement.
- Perform continuity test to both section of bus duct to be joined to ensure proper connections. If satisfactory readings cannot be achieved, remove and replace mal-functioning busbars with new units and retest.
- Measure resistance between phases, phase and earth using megger. (The mega ohm readings should not be less than the value recommended by the manufacturer.)
- Upon installation, measure resistance of each major branch. In case of low readings, re-tighten all joint bolts in the busbar section being tested using torque wrench. If satisfactory readings cannot be achieved, remove and replace mal-functioning busbars with new sets and retest.
INSPECTION & TEST PLAN
- The engineer should verify that the supervisor/foreman with construction responsibilities for installation is familiar with this method statement and is issued with copies of the inspection checklists and test plans.
- The engineer should satisfy the procedures provided by QA/QC inspections to ensure the as-installed condition of the Busbars installation meets the specified engineering requirements and approved drawings.
- As part of the assessment, the QC Inspection Procedures must ensure a quantitative or qualitative acceptance criteria for determining the prescribed activities have been accomplished satisfactorily.
- The QC inspection personnel. in coordination with Site Supervisor, should verify that the quality of the related Busbars installation activities is within the prescribed criteria.
- The Supervisor should verify any as-built record of Busbars installation. and confirm that the information meets the project requirements.
- Quality Control Engineer along with Project Engineer and Site Supervisor will monitor that all components are installed as per contract specifications and approved submittals.
- Request for Work Inspection Request (WIR) shall be submitted by Site Engineer for verification and inspections.
- Readable stamped approved drawing to be available during installation and inspection.
- Arch. approval for wall/ceiling to be attached with WIR.
- All the equipments engaged for testing shall have a valid calibration and certificate should be furnished.