This method statement describes the various steps to be taken during the installation of cables and its associated works, etc.
Preliminary Survey & Route Approval
After survey has been conducted and formal approval from ELECT.COMPANY “Notice of Intent” to all the concerned authorities shall be issued indicating the selected route and length to avoid damage to underground utilities / services of the various installations and take necessary approvals (ADM, Etisalat, TPD etc.).
After a trial pit is made excavation shall be carried out either manually or by machines taking all the precautions to avoid damage to underground services (if existing). For 33 kV cables, 50 cm. wide at bottom and 1.1 m. deep trench will be made; for 11 kV cables, 50 cm. wide at bottom and 1 m. deep trench will be made; and for LV cables, 40 cm. wide and 75 cm. deep trenches will be excavated. The excavated trench shall be kept dry during cable installation. Dewatering shall be carried out incase water is found in the trench and all necessary care will be taken to dispose off water as per ELECT/ COMPANY instructions. The trench shall be straight and free from any sharp materials. The excavated trenches shall be protected by safety measures such as, providing picket fence, danger notices, barriers, warning lights etc. (if necessary) for public safety.
The cable shall be laid straight in the center of the trench. If trenches run parallel to the existing services / cables, at least a distance of 0.5 mtr. shall be maintained. The trench shall be filled with 10cm layer of sieved soft sand and then another layer of 10cms. Soft sand shall be filled after laying of the cable. Then cable-covering slabs shall be laid on the sand bed. At the joint locations, cable shall be laid with their ends over lapping for a length not exceeding 1 mtr. Bending radius shall be according to the overall diameter of the cable (12D to 20D). The trench shall be backfilled carefully with Warning tape having a thickness of 150 microns with ELECTRICAL COMPANY standard markings. Later the trench shall be compacted as per the instructions of ELECT. COMPANY Engineers or depending on the site conditions or grade of cable.
Testing of the laid cable shall be carried out as per ELECTR.COMPANY requirements / instructions such as meggering (Insulation resistance & pressure testing).
Road Crossing Ducts / Thrust Boring or Directional Drilling
All necessary precautions, approvals shall be taken prior to commencing / starting of the works. Road crossing ducts shall be installed at a depth of 90 cm. from the road surface / top for paved roads and as per instructions of ELECT.COPANYEngineers for unpaved roads. The thickness and diameter of the ducts shall be as per specifications (100mm / 150mm / 200mm generally). Thrust Boring / Directional drilling shall be carried out if cutting of Asphalt is not allowed by the concerned authorities. (Method statement for such works can be given during approval, if so required).
Removal & Reinstatement of Interlocking / Side Walk Tiles, Kerb Stones
All necessary permission shall be obtained prior to removal of such Tiles. The removed Tiles / Kerb stones shall be reinstated in its original shape / forms. The damaged Tiles / Kerb stones shall be replaced by new identical shape & color to the existing ones. Coarse sand shall be spread on all affected areas, of not less than 20 cm. and compacted till its original uniformity is restored. The work shall be carried out in accordance with ADM requirements and necessary Bank Guarantee shall be given for proper performance of the work.
All proposed / approved locations for installation of Equipments shall be properly leveled, rammed and compacted.
The required / suitable concrete base shall be pre-cast and carefully transported to the site with the Equipment. (Approval for such casting works shall be taken well in advance from ELECTRIAL COMPANY giving the method statement & grade of materials used, generally as per specifications).
Earthing of all installed Equipments will be carried out as per general instructions of the ELECTRICAL COOMPANY Engineers and to comply with British code of practice CP-1013.
All equipments shall be tested prior to commissioning / energizing and full test report / details will be submitted to ELECTRICAL COMPANY well in advance for approval.
Implement necessary safety precautions throughout the operation.