Technical Specification of Roof Top Tower of 12, 15, 18 & 21m height

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To Plate Earth e. Earth conductor should not be encircled with metal clamps while taking it along the wall. This is essential to eliminate the high inductive reactance that will impede the flow of surge current along the conductor in case of lightning. f. Earthing conductor shall not pass through any metallic conduit or pipe as this will increase surge impedance. OUTDOOR GROUNDING BUS BAR To Plate Earth TOWER PLATEFORM FEEDER GROUNDING CARD FEEDER LIGHTENING ARRESTER MOUNT GROUNDING WIRE Figure – 2 LIGHTENING ARRESTER MOUNT INDOOR GROUNDING BUS BAR GROUNDING STRIP 50 mmX3 mm Earthing arrangement using outdoor grounding Bus bar and indoor grounding bus bar GROUNDING WIRE UTL/RTT/02-01 OCT 2011 Page 28 of 31 BTS SMPS
3.1 The bidder shall provide two numbers of GI plate earth (one for Tower and the other for equipment) located at least 3 metre apart and shall be connected by 50mm x 3mm GI strip for maintaining common potential (Figure-2). Each plate earth system shall have ohmic value ≤2Ω. 3.2 Each earth plate (Figure-1) shall include excavation of pit of size 1000x1000x2000mm in all kinds of soils and placing four numbers of GI plates of size 300x300x6 mm vertically at diagonally opposite ends in the excavated pit and inter connecting the plates with 4 Nos. of 50x3mm G I strips with 2 Nos. of GI bolts and nuts of 10mm dia. at each connection and covering the joints with bitumen, placing GI pipe of 50mm internal diameter (B Class) and 2000mm length at the center of the plate grid for watering and filling the pit with fine ash and / or finally sieved good quality soil including ramming in 20 cm layers etc. complete and cover the pit with 750x750x50mm thick precast reinforced cement concrete slab having 100mm dia. hole at the centre to pass the GI pipe and construct a chamber of internal size not less than 280x280x250mm with half brick wall including fixing CI manhole cover of size 300x300mm of weight not less than 7.20 Kg. (cover & frame) and plastering the chamber on all sides with cement mortar 1:4 of 12mm thick (1 cement : 4 fine sand) and including disposal of surplus excavated earth if any. 3.3 The bidder shall provide GI strips of size 50x3 mm one end connected to the tower leg with GI bolts and nuts [with lead sheath in between] at the bottom of the tower and the other end shall be connected to the GI plate earth with GI bolts and nuts [with lead sheath in between] including clamping the down lead flat to walls/stems without any sharp bends using necessary clamps and screws. 3.4 The bidder shall provide GI bus bar of 50 x 3 mm or 50sq. mm Copper cable (PVC insulated) connected to the lightning conductor and to the leg of tower (where one plate earth is terminated) with 2 Nos. of 10 mm diameter GI nuts & bolts [with lead sheath in between] at each connection. The bus bar shall be drawn through heat shrink sleeve and shall be shrunk properly. The bus bar/cable shall be clamped to the tower walls at uniform interval of 1.5 M. using proper clamps and insulators such that the bus bar shall be well insulated from the tower/building walls all complete. 3.5 The bidder shall terminate separate earth strips from the two earth pits up to indoor and outdoor grounding bus bar (i.e. one earth strip from first pit to indoor grounding bus bar and another from second earth pit to outdoor grounding bus bar) as per figure-2. *** UTL/RTT/02-01 OCT 2011 Page 29 of 31
Page 1 and 2: Technical Specification of Roof Top
Page 3 and 4: Table of Contents Chapter Title Pag
Page 5 and 6: Material: M-20 grade concrete shall
Page 7 and 8: 10.0 Verticality The verticality fo
Page 9 and 10: 18.0 Bill of Material 19.0 Design T
Page 11 and 12: Sl. No. DESCRIPTION COMPONENT SIZE
Page 13 and 14: 2.1.1 Details of Nuts, Bolts & Wash
Page 15 and 16: 2.2 Bill of Material for 18 M Roof
Page 17 and 18: Sl. No. DESCRIPTION FEEDER COMPONEN
Page 27: Notes: Chapter-3 Specifications for
Page 31: Chapter-5 Key Diagrams UTL/RTT/02-0

Technical Specification of Roof Top Tower of 12, 15, 18 & 21m height

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