PROVISION OF LIGHTNING ARRESTER AND SURGE PROTECTION SYSTEM ALONG WITH ASSOCIATED WORK E AND M AND B AND R AT CERTAIN LOCATIONS PHASE II AT AF STN CHIMNEY HILLS BANGALORE

Amount

Supply & Fix Air termination single pointed, copper rod 12mm dia 600 mm long all as specified and as directed

LIGHTENING PROTECTION WORKS :- Chemical earthing complete with copper earth plate electrode 900 mm x 600 mm x 5 mm thick buried directly in ground (Earth pit not less than 5.15 m deep below ground level) with top edge of the plate not less than 4.25 mtr below normal ground level connected to and including copper strip lead 32 mm x 6 mm size by means of copper brazing strip and layers of charcoal & magnesium sulphate including funnel with wire mesh and testing of earthing all as specified by Engineer-in-charge. (a) Earthing has to be done in presence of Engineer-in-Charge.(b) For Chemical earthing , Charcoal small pieces - 75 Kg, salt (crystal) - 250 Kg, Magnesium sulphate (crystal) - 100 Kg shall be used. (c) Copper strip shall be braced with copper plate electrode. (d) Alternate layers of charcoal and salts should be laid in the earth pit on the top of copper plate at least in 5 layers . (e) After laying the 5 alternate layers of charcoal and salt, two layers of magnesium sulphate has to be laid.(f) The chemical salt and magnesium sulphate should not be mixed but are to be laid in layers only. (g) Earth pit cover shall be painted with yellow colour on top side and details has to be written in block letters, with black paint i.e , date of earthing done, resistance value, name of eqpt connected etc, and earth pit indicators made with MS plate of 3mm thick, triangular shape, size 15 cm width & 15cm height welded/ rivetted to suitable 10mm dia MS rod / MS flat 45cm length painted in red colour for easy identification and to be suitably grouted 30cm above ground level near earth piy. (h) During execution of work pour sufficient water in earth pit before and after doing earthing. (j) 25 mm dia GI pipe medium grade of suitable length fitted to funnel covered with meshalong with cap has to reach just above copper plate for pouring water. (k) Soft soil ( Black cotton soil) shall be used in case of rocky terrain.(l) Brass nuts & bolts with proper washers shall be used for copper strip jointing and necessary bracing shall be done as directed. (m) Copper strip beyond 7.5 m shall be measured and paid separately.(n) The test point pit shall be made as directed.(o) The test report shall be submitted in triplicate. (p) Construction of earth pit chamber shall be with PCC (1:3:6) type C1 , using 20mm grade stone aggregate, RCC 1:2:4,type B-1 cover, 50mm thick with 8 mm dia TMT bar 100 mm centre to centre with lifting handles of suitable dia complete all as directed by Engineer-in-charge. Note :-1. Earth resistance should be less than 1 Ohms. 2. After completion of work, while doing testing, desired earth resistance is not obtained contractor has to redo the earthing at his own cost.

M&L copper strip earth continuity conductor or main earthing lead of size 32 mm x 6 mm fixed on wall/ floor/roof or any other surface with porcelain insulators and all joints should be by means brazing and all as specified and as directed

M&L submain wiring with PVC insulated, single core, multi stranded, 1100 volts grade unsheathed copper conductor cable in and including PVC Conduit with accessories fixed on camera poles with clamps & screws complete with 3 runs of 4.0 sq mm copper conductor all as directed. (for surge protection connection)

Supply, Install and testing of Surge protection device, single phase 1P+N- I max 15 KA Type 2 with necessary connecting accessories including PVC enclosure. Make :- L&T cat No. AUSP021PN15 or equivalent in Schnieder/ABB

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