REPAIR REPLACEMENT OF EARTHING INFRASTRUCTURE AND ALLIED INTERNAL WORKS AT AF STN UNDER GE AVADI

M&L for in replacement of earthing complete with copper earth plate electrode of size 60cm x 60cm x 3.15mm thick burried directly in ground vertically at a depth not less than 2.25 metre deep below normal ground level with top edge of the plate not less than 1.5 metre below normal ground level surrounded from all sides by 15 cm thick packed layer of charcoal dust and common salt, filling in alternate layer and electrode connections by using copper strip 20 x 3mm dia by means of bolts, nuts, check nuts and washers made of copper or brass and protected by light grade 15 mm dia GI pipe connected to main switch board or main control board, and GI pipe light grade 20 mm bore for watering and including funnel, wire mesh, including test results alongwith excavation and earth work, disposal of surplus soil to a distance not exc. 50 mtr all as specified and as shown on Plate No 5 of SSR Part I (2009) all as specified and directed by Engr-in-Charge.

All as per Item No.1 above but for galvanised steel earth plate electrode of size 60cm x 60cm x 6mm and galvanised iron strip 25×4mm dia

All as per Item No.1 above but for galvanised earth lead wire 4.0mm dia Earth wire.

Material & labour in replacement of chemical earthing complete with copper earth plate electrode size 900mmx600mmx5mm thick burried directly in ground vertically with top edge of the plate not less than 3.5m below normal ground level (The depth of pit not less than 4.25m below normal ground level), earth plate surrounded by packed layers of mixture of magnesium sulphate (MgSO₄) - 100Kg, common salt - 200Kg, Charcol dust - 300Kg and also mixing of Bentonite not more than 25 Kg with water, electrode connected with & including earth lead of copper strip 32x6mm by means of oxycetelane copper brazing as directed by Engineer-in-Charge, and other end of the earth lead connected to main switch board or main control board or test point or equipment, earth lead protected by galvanised iron pipe light grade (ISI marked) 50mm bore alongwith watering pipe 20mm bore GI medium grade (ISI marked of specified make), funnel with wire mesh, including all necessary excavation & earth work, PCC chamber in plain cement concrete (1:2:4) type B-1 & RCC cover (in lieu of CI cover), all as shown in electrical plate No. 2 of MES Schedule Part-I (2009), complete all as specified and directed. Note(s) :- (i) RCC pit cover shall be pre-cast of RCC (1:2:4) type B-1, 80mm thick reinforced with XPM not less than 4Kg/Sqm. (ii) Rate shall include copper strip and protection pipe of length 7.5m, excess beyond 7.5m length required at site shall be measured and paid separately. (iii) Earth resistance should be less than 1 Ohm. In case the test results are not found below 1 Ohm, complete earthing will be redone without any extra cost to Govt.

Material and labour for in replacement test point terminal block made of gun metal or phosphorus bronze or copper, size 75mmx75mmx25mm, drilled and screwed including 3 nos. 8mm dia 25mm long hexagonal head screws, complete all as specified and directed.

Material and labour in replacement Air termination, single pointed aluminium rod 12mm dia and 300mm long, including making connection to earthing conductor, fixed as in replacement of old termination rod, complete all as specified and directed.

Supply and fix in replacement of GI pipe 25mm bore light grade (ISI marked), cut piece of 1.0 metre - 1.5 metre length or as directed by Engineer-in-Charge, fixed vertically with bottom end embeded in & including cast-insitu PCC (1:2:4) block of size 20cmx20cmx15cm including use and waste necessary fair finish form work, and other end (at top) fixed to air termination rod with necessary bolts, nuts etc as required, complete all as specified and directed.

Supply, Install, testing and commissioning in replacement of lighting flash/strike counter in water and weather proof, digital display facility, current discharge capacity > 1 KA, IP 65 protection with enclosure for analyzing the frequency of lightning strikes and effectiveness of the lightning protection system in place and connected to down conductor with mounting arrangements with GI mast tower or Building wall surface and suitable fixing arrangements with standard accessories etc complete as per specification and as required complete all as specified.

Supply and fixing in replacement of porcelain supporting insulator of as per existing size/adequate size fixing, on wall/roof for supporting the earthing strips, fixed as in repairs, complete all as specified and directed.

M&L for in replacement of recharging the earthing of 32mmx6mm copper strip by providing charcoal dust and earthing salt & including excavating, return filling and test results should be obtained as specified and as directed by Engr-in-Charge