CWE/AF AMB/AMB-12/2022-23 IMPROVEMENT OF EARTHING INFRASTRUCTURE AT AT AF STN AMBALA UNDER GE (AF) AMBALA

Amount

Supply, Installation, Testing, and Commissioning of a set of maintenance free tripod earthing system consisting of 3 No. of Copper Bonded Earth Rod of 10 feet length, 17.2 mm dia made of high tensile low carbon steel circular rods, molecularly bonded with 99.9% electrolytic grade copper on outer surface (minimum copper bonding thickness-250 microns) with exothermically jointed copper busbar of 150mm x 50mm x 6mm for long lasting and connection . Each copper bonded rod and the exothermically jointed busbar both should be CPRI tested on at least 25KA Fault current to ensuring the high current carrying capacity of the system and earth rod should be certified by Underwriters laboratories confirming to comply with UL467 international standard for grounding and bonding equipment. Each rod should be used with minimum 50kg earth enhancing compound that should be ROHS tested and have passed , Resisitivity of the earth enhancing compond should be less than 0.05 ohm meter - an international standard for Earth Enhancement Compound by NABL accredited Lab complete all as specified & directed. Notes: (i) The rate for interconnection of tripod earth with Copper strip of size 20mm x 3mm and polycarbonate earth pit cover-03 Nos. shall deemed to be included in the quoted rates.

Notes for BOQ item No. 1.00 continued: (ii) The Earth result should be less than 1 ohm for two year and will be the responsibility of the contractor without any extra cost to department. (iii) The earthing shall comply to IS 3043, UL 467, BS/EN 50164-7. (iv) To obtain less than one ohm if a combination two or more earthings are to be interconnected or the length of the electrode is to be increased, it shall be measured and paid as one earthing only without any extra cost to department. (v) Testing of the earthing shall be carried out in presence of rep of Accepting officer, rep of User(i.e. IAF), rep of GE & Contractor, the cost of the same is deemed to be included in the quoted rates. (vi) A Security deposit (in form of retention money or FDR) against Guarantee of earthing resistance for the period two years from the certified date of completion shall be submitted by contractor @ 5% of work done amount of this item. (vii) The cost of the above aspects and cost of Earthwork (if any) are deemed to be included in the quoted rates.

M&L earth continuity conductor or main earthing lead on FRP/PVC/Ceramic insulator fixed to wall on batten or recess or chases or buried in ground or drawn in conduit/pipe or fixed to poles or any other indicated situation for loop earthing etc. as required copper strip 20mm x 3mm complete all as specified & directed

M&L air termination single pointed aluminium rod 12 mm dia, 300mm long duly fixed/secured with PCC or with GI pipe supports complete all as specified & directed. Note: PCC and GI pipe for fixing shall be measured & paid separately.

M&L test point terminal block made of gun metal or phosphorus bronze size 75mm x 75mm x 25mm drilled and screwed with and including 3 nos, 8mm dia, 25mm long hexagonal head screw complete all as specified & directed.

M&L earthing complete with with copper earth plate electrode 60 cm X 60 cm X 3.15 mm thick buried directly vertically in ground to depth not less than 2.25 mtr below ground level, with top edge of earth plate not less than 1.5 mtr below ground level surrounded from all sides by 15cm thick packed layer of Charcoal dust & common salt filled in alternate layers and electrode connected to copper earth lead strip 25mm x 3mm upto 7.5mtr long by means of bolts, nuts, check nuts and washers of galvanized iron and connection to earthing test point & earth dolly & watering pipe medium grade GI 20 mm bore including protection pipe GI light grade 40mm bore, including wire mesh, funnel, lugs, salt, charcoal dust, excavation in any type of soil, returning filling & removal of surplus soil upto 50mtr, pit chamber shall be of PCC 1:3:6 type C-1 using 20 mm graded mechnically crushed stone aggregates and pit cover slab 50mm thick shall be of Precast RCC 1:2:4 type B-1 using 20 mm graded mechnically crushed stone aggregates reinforced with welded steel wire fabric or XPM weighing not less than 4Kg/sqm with cast iron frame including necessary form work complete all as shown in electrical plate No 3 of SSR part-I, including testing on completion at site complete all as specified & directed. Notes:- (i) Any variation in length of earth lead and protection pipe of earth lead shall be adjusted through DO. (ii) On testing if the desired earth resistance is not obtained, earthing will be generated at No extra cost, till the desired earth resistance is obtained. (iii) The chamber shall be constructed atleast 1.5 mtr away from the earth electrode.

S&F alumininum strip 25mm x 3.15mm on FRP insulator fixed on wall/MS sheet or floors including connecting to lightening arrester/earthing/test point, strip should be brazed/welded/Soldering/double nut bolt at each joint complete all as specified & directed.

M&L PCC 1:3:6, type C-2 (using 40 mm graded mechanically crushed stone aggregates) as in blocks to hold GI extension pipe for air termination rod including necessary form work complete all as specified & directed.

M&L GI pipe 40 mm bore, medium grade as in trenches, under road,under floor, fixed to wall with fixing arrangement with suitable size of MS clamps made from 40mm x 3mm size flat iron including nuts, bolts & washers or along the pole with fixing arrangement etc complete all as specified & directed .

S&F 32mm dia (external dia) rigid non-metallic, heavy duty, PVC conduit exclusive of boxes (junction/terminal) but inclusive of all tees, bends, elbows, reducers, bell mouth tube ends and fixing accessories such as couplers, locknuts, saddles, pipe hooks etc. complete all as specified & directed.

M&L brazing of copper strips at joints of earthings at site by disconnecting existing nut bolts, shifting brazing machine at site. Brazing by using brazing rods, piece of Copper strips etc complete all as specified & directed. Note:- (i) Length of brazing upto 5cm on one spot shall be considered as one unit. (ii) The size of copper strip shall be minimum 20mm x 3mm or as directed by Engineer-in-charge. (iii) The work against this item shall be carried out on locations/ spots other than covered in BOQ item No 1.00 here-in-before.

Raman Electric Trading Co

Esha Engineers

Rahul Enterprises

M/s Dhapola Elevator and Engineering

m/s parmod kamar