Below is the detailed cable tray installation method statement not only for cable tray but also applicable for GI ladder and trunking for indoor and outdoor applications and in service rooms like pump rooms, electrical rooms and plant rooms etc.
All materials intended for cable tray, ladder and trunking shall be submitted for approval of the consultant as per the standard procedure using the Notification of permanent material received at site. Material samples shall be submitted as required by the consulting engineer for approval.
Electrical site supervisor will complete the inspection checklist and follow the Inspection & Test Plan detailed in this procedure.
Intent of this procedure is to establish a high level of assurance that the end product meets the specification requirements.
QA/QC Inspectors should verify the approved procedures are followed and the inspections and testing records are completed.
All operatives will attend safety induction along with the relevant document copies i.e. valid visa company ID copy, and copy of previous experience and training in the same job which proves his competency.
Supervisor should closely monitor the activity, if he finds any operative is lagging on safe work competency, he will be sent for re-induction and even retraining if deemed necessary.
Examine the areas to execute the work and the conditions under which the work will be performed. Identify conditions detrimental or unsafe for the proper and timely completion of the Work. Do not proceed until unsatisfactory or unsafe conditions have been corrected.
Examine the areas to execute the work and the conditions under which the work will be performed. Identify conditions detrimental or unsafe for the proper and timely completion of the Work. Do not proceed until unsatisfactory or unsafe conditions have been corrected.
Material Storage and Handling
Site quality team shall submit material inspection request upon receipt of materials on the project site, by attaching delivery receipt, material submittal approval and other documents to show complete compliance with specifications.
Any material found not as of approved material or with surface damage which is not rectifiable will be set aside, these materials will be labelled rejected and returned to supplier warehouse and a Non-conformance Report will be issued to the supplier by QA/QC superior.
Store keeper is responsible to store materials in protected dry location off-ground in accordance with manufacturer’s instructions and to protect from mechanical damage or weather effects.
Extreme care shall be taken while handling the cable trays, ladder tray and trunking materials.
Lay down area at site to be coordinated and arrangements to be made for unloading and / or mobilization of materials.
Ladders / Scaffoldings to be secured firmly over the working platform and inspected by competent personnel and tagging system (green/red) are implemented, prior to start of work.
Prior to commencement of work, the Engineer / Supervisor/Foreman will inspect all materials delivered to work place in order to confirm that these are the relevant pieces for the site and materials are not damaged, these are without excessive scratches or visible corrosion.
Only required materials to be shifted to site and stored temporarily and ensure extra materials are not dumped to site and congest the working area.
Once work is completed extra materials and tools to be returned back to stores, work area to be kept clean.
Cable Tray Installation General Requirements
Approved site fabricated trays shall be used as per site conditions.
Only approved brand cable tray, ladder tray and trunking shall be allowed to be used.
Ensure that sleeves and box outs are as per approved shop drawings and specifications, these must be done during the construction of structural elements.
Manufacturer’s standard fittings shall be used and where manufacturer fittings are inadequate as per site requirements site fabricated fittings shall be used as per consultant approval.
Mark the location of installation and install the approved cable trays, trunking and ladders as per specifications, shop drawings and site requirements for individual cases like slab or wall etc.
In the case of hollow block expansion bolts (unifix) will be drilled and C-Channel will be installed at the regular intervals. Trays and trunking shall be fixed on c-channel using suitable bolts sized as per load of the tray & trunking and as per approved mock-up. Supports shall be installed as per specifications.
Ensure cable trays, ladders and trunking are installed neatly on the surface and be truly vertical, horizontal or parallel with the features of the building.
Wherever the accessories like Tees, Flat Elbows, Reducers & the jointing of two straight runs are required it should be provided with support in 300mm distance from joint.
Sets and bends shall be sized to allow for the minimum permissible radius of the largest cable on the tray.
Earth continuity strips shall be installed at all joints and fitting connections. Separate grounding cable for cable trays/ladders/trunking shall be provided and connected to earth bar.
Burs and sharp edges shall be removed prior the installation of the trays, trunkings and accessories. Approved galvanized paint shall be applied on the cut edges to protect from rusting.
Ensure load bearing cleats are provided in the vertical cable trays.
Joints shall be kept as close as possible to the supports.
A minimum space of 75mm shall be maintained between installations and building structure in order to secure the cables and for general maintenance.
Expansion joints shall be provided in the cable trays where it passes through the building expansion joint.
Approved sleeves shall be provided where cable tray passes through a floor or fire barrier, the same shall be sealed with fire resistant sealant / fire stop materials.
After the completion of a section of cable tray/trunking continuity test shall be performed to ensure continuity of the system.
Fix identification stickers for the power cable trays and ELV cable trays and other ELV services accordingly.
GI Cable Tray Installation and Trunking in the Roof Area
All the supports in the roof area shall be provided as per the approved roof coordinated MEP services installation details drawings.
Pedestal shall be provided for the floor mounted supports for the cable trays and trunking.
All the supports for the roof area floor supports shall have the mounting legs with the opening (holes) for the fixing.
Cable trays and trunking installed at the roof level shall be covered with the cable tray covers according to the size of the cable trays and trunking. (For the Top layers only which is exposed direct to sun)
All the cable trays and trunking covers shall be secured with proper clamps or screws fixed with supports.
Ensure the gaps between the trays which are mounted in tires are sufficient for the cable laying as per the approved installation details drawings.
Cable Ladder and Cable Tray Installation Steps
After the civil clearance to proceed with MEP installations, ensure the area is clean and ready to start the cable tray installation works.
Ensure all the relevant latest approved shop drawings are available with the electrical trunking and tray installation team.
Required quantity of standard length of cable trays / ladders are shifted from site stores to the work place with the help of cranes and/or wheel barrow.
Clean all the cable trays and trunking from all debris and dust etc.
Mark the cable tray / ladder routes as per approved shop drawings, ensure these are of horizontal and vertical runs only, except where it is not practicable and approved by consultant.
Coordinate the routes, levels and ensure there are no clashes with other services.
Maintain a minimum of 150 mm clearance from other mechanical services.
Make the holes and fix the cable tray supports with appropriate metal plugs, mounting brackets with base plates and nuts, ‘L’ angles / slotted ‘C’ channels and nuts.
A maximum of 1.2 meter distance is maintained between the supports to avoid sagging of cable trays / ladders.
Provide supports at 250 mm from bends, branches and offsets.
Cut the standard length of Cable tray / ladder to required length with appropriate cutting tools and fixed with the necessary accessories.
Manufacturer’s instruction for installation shall be followed.
Ensure the installation of cable tray / ladder are neat, in straight line for good aesthetic look.
Trim the extra projected supports.
Approved fire sealant shall be provided wherever the cable tray / ladders installation crosses the fire rated walls.
Copper earth links shall be installed at every joints to maintain continuity throughout the installation, later this continuity is tested and recorded.
Provide identification labels as specified to identify the electrical service.
Cable tray covers shall be provided after the cable installation activities are completed, wherever it is exposed to direct sun light.
Cable tray installation inspection request shall be raised for Consultant’s inspection and approval.