REPAIRS / REPLACEMENT OF EXISTING EARTHING, LIGHTENING ARRESTER AND ASSOCIATED MISC WORK AT AF STN SURYALANKA

Taking down carefully existing Copper strip of various size fixed in position as lightening conductor from roof/wall and buried in ground including making good the disturbed surfaces etc complete all as specified and directed by Engineer-in-charge.

Supply and Fixing in repair copper strip of size 32 x 6mm buried not less than 60cm deep into ground, fixed to wall with saddles including necessary nutbolts, screw, rivets, PVC blocks, porcelain insulator all fittings and joining materials connected and testing complete all as specified and directed by Engineer-in-Charge.

Taking down carefully existing GI strip of various size fixed in position as lightening conductor from roof/wall and buried in ground including making good the disturbed surfaces etc complete all as specified and directed by Engineer-in-charge.

Supply and Fixing in replacement of GI strip of size 32x6 mm in position with burried the strip of depth not less than 60cm where directed and fixing on wall/plinth with nessasary arrangements at any height after proper cleanig, obtained from item no.1 Note :- All T&P required for fixing of old strip will be arranged by contractor and the rate are deemed to be included in the quated rate

S&F in repair GI pipe medium grade 40mm dia bore fix to wall/ PCC block etc with suitable clamp complete all as directed by Engineer-in-charge.

M&L Chemical earthing complete with copper earth plate electrode of size 90cmX60cmX5mm buried directly in ground, earth pit not less than 2.25 mtr dept below ground level and 1.25 mtr width with top edge of the plate not less than 1.35 mtr below ground level, Charcoal of 250Kg, Salt Crystal of 200kg and Magnesium Sulphate Crystal of 100kg to be used in pit, alternate layers of charcoal and salt should be laid in the earth pit on top of copper plate and electrode connected with copper strip of size 50mX6 mm by means of copper brazing , GI pipe light grade of 80 mm bore as protection pipe, copper strip of length not more than 7.5 mtr and connected to test point. GI pipe 25mm dia medium grade of enough length to reach just above copper plate fitted with funnel with wire mesh, along with cap and running water tap to be provided for keeping the soil wet, PCC pit with PCC (1:3:6) pre cast chamber of internal size 40X12X30 cm and PCC cover of size 42X42x4cm with PCC (1:3:6) including excavation and earth work disposal of surplus soil to a distance not exceeding 50 mtr as shown on electrical plate No 3 of SSR-2009 complete all as specified and confirming to IS 3034-1987 : Code of practice for eartthing all as specified and as directed. The following precautions to be observed while errecting the earth pits :- (i) The copper plate and the copper strip to be brazed. (ii) Alternate layers of charcoal and salt should be laid in the earth pit on top of the copper plate. At least five layers to be laid. (iii) After laying of five alternate layers of charcoal and salt, a 2 in ch layer of magnesium sulphate needs to be laid.Balance volume of to be filled with soft soil. (iv) The chemical, salt and magnesium sulphate should never be mixed but are to be laid in layers only. (v) Ceramic spacer to be placed between the copper strip and the wall while extending the earth to the equipment. Large holes not to be drilled into the copper strip for fixing ceramic spacers.

M&L For MS sheet of size 30 x 20cm thickness of 2mm shape of triangle and if triangle each side will be 30 cm from coner to corner including 25x3mm MS angle orin by welding 10cm 'T' AI in bottom of stand (90 cm long) to grouting with PCC (1:3:6) type C-1 (using 20mm graded stone aggregates) of size 150x150x150mm below ground level, framed work, earth works etc including two coats of synthetic enamel paint over a coat of red oxide primer and making of TESTED on_____ RESULT _________with different colour of synthetec enamel paint with suitable size of letters and all arrangements complete all as specifed and directed