UPKEEP OF EARTHING AND LIGHTING ARRESTER INFRASTRUCTURE AT AF STN DARBHANGA UNDER GE AF BIHTA.

Amount

Earth continuity conductor or main earthing lead 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 complete all as specified with & including the following: -

Copper strip of size 20mm x3mm. .

Aluminium strip of size 25mm x3.15mm.

NOTES : (a) Strips to be fixed with porcelain / polymer insulators at the intervals of 0.6 metre so as not to be in electrical contact with building structure. (b) Brazing shall be done on both sides (overlapping) at all joints except test point.

Test point terminal block made of gun metal or phosphorus bronze size 75x75x25mm drilled and screwed including 3 nos. 8mm dia 25mm long hex. head screw complete all as specifed and directed.

Air termination, single pointed aluminium rod 12 mm dia 300 mm long complete all as specified.

40mm bore medium grade GI tubes, with necessary GI fittings laid in floors / wall complete all as specified

Rigid non metallic, PVC conduit, 40 mm bore, medium grade, ISI marked, inclusive of all fitings (such as junction boxes, bends, elbows, tees, reducers, bell mouth tube ends) and all fixing acessories such as couplers, lock nuts, saddles, pipe hook etc. for sub main wiring and the like complete all as specified.

Tripod Earthing (3 Set earthing inter-connected to 1 set) maintenance free Earthing Solutions comprising with the followings: (i) Supply and fixing after digging bore of suitable size the CPRI tested and UL certified maintenance free earthing system having a set of copper bonded Earth Rod of 3.5 meter length, 17.2 mm dia made of high tensile low steel circular rods, molecularly bonded with 99.90% electrolytic grade copper on outer surface(minimum copper bonding thickness-250 microns) inserted in GI pipe light grade of 25 mm dia as in P-I-P (Pipe-In-Pipe) technology and back fill by carbon based earth enhancing compound, with exothermally jointed copper bus bar of 200X25X6mm for long lasting and connecting to the Earth Copper bonded rod & exothermically jointed bus bar should be CPRI tested on 25KA fault current complete all as specified and directed by Engr-in-charge for complete connections.-Qty 3 Nos. (ii) Current carrying capacity of Earth Copper bonded Electrode shall be 25KA/Sec. (iii) Supply and filling of carbon based, eco friendly earth enhancing compound of RoHS tested compound tested by NABL accredited Lab in compliance to IEC 62561-7 and having passed leaching, sulphur, corrosion resistivity test as per IEC 62561-7 an international standard for earth enhancement compound in compliance to IEC 62561-7 with a resistivity < 0.12 ohm-m , 25 kg of Jam Lite/Equivalent.Qty- 3 nos.

(iv) Earth enhancing compound shall be free from corrosion, it shall be carbon based material and shall be free from bentonite and other hazardous substances.The product does not dissolve, deteriorate or leach out with time. It shall be highly conductive and improves earth's absorbing power and humidity retention capability. It shall be eco-friendly and chemically inert to sub soil. (v) Supply and fixing PCC earth pit block of 1:3:6 type C-1 of size 45 cmx45 cmx20 cm (Using 40 mm graded crushed black trap/ granite/ Basalt stone aggregate) alongwith plastic casing in the internal periphery of the pit for protection, with ms angle iron of 20*3 and pit covered with chequred plate openable lid of size 300x300x5 mm as an inspection chamber -03 Nos. NOTE:- (i) 3 Sets earthing inter-connected shall be treated as 1 set and the cost of copper earthing strips of size 20X3mm used for inter-connections are included in the quoted rate. (ii) Testing shall be done in a straight line after completion of job and if the desired earth resistence is not found i.e. below 1.00 Ohms , the earthing shall be re-done by the Contractor at no extra cost. (iii) Painting of Earth pit and cover in Red colour for chemical earthing shall be included in the quoted rate. (iv) 05 years "Performance Guarantee" as mentioned in PS clause 19.1.5

Conventional type earthing complete with Copper earth plate 600 mm x 600 mm x 3.15 mm thick buried directly in ground vertically in pit of depth not less than 2.25 mtr below normal ground level with top edge of the earth plate not less than 1.50 mtr below normal ground level connected to continuous (without joint) copper strip 20×3 mm as earthing lead by means of bolts, nuts, check nuts and washers of brass connected including single test point terminal block made up of gun metal or phosphorus bronze of size 75 mm x 75 mm x 25 mm drilled and screwed including 3 Nos 8 mm dia 25 mm long hexagonal head screwed all as specified, excavation and earth work and disposal of surplus soil with vertically inserting 40 mm bore Gl tubing light grade and necessary fitting for protection of Gl strip including laying of charcoal dust and common salt in alternate layer of not less than 15 cm each surrounding upto the height of the plate and PCC earth pit block of 1:3:6 type C-1 of size 45 cmx45 cmx20 cm (Using 40 mm graded crushed black trap/ granite/ Basalt stone aggregate) alongwith plastic casing in the internal periphery of the pit for protection, with ms angle iron of 20*3 and pit covered with chequred plate openable lid of size 300x300x5 mm - 01 nos as an inspection chamber, GI medium grade watering pipe 20 mm dia with funnel and wire mesh, 15 mm thick rendering in cement mortar 1:4 internally and upto 150mm below ground level & externally. GI funnel with wire mesh , complete all as shown on electrical plate No.3 of SSR Part -1 (2020 ) and connected in earth test including testing and writing test results on a 3.00 mm thick painted mild steel earth pit marking plate (200 mm x 100 mm) duly welded with a 450 mm long 100 mm dia round MS rod fixed with the earth pit chamber by grouting complete all specified and directed.

NOTE:- (i) The unit rate quoted is deemed to be inclusive of cost of Earth test point terminal block and test result marking plate with MS rod. (ii) Both earth strip and protection pipe upto 7.5 metre beyond the earth plate electrode shall be included in the quoted rate. (iii) Painting of Earth pit and pit cover in Yellow colour for conventional earthing shall be included in the quoted rate. (iv) THe cost of marker/identifier shall be quoted and paid separately under respective item (iv) On testing, after completion of job ,if desired earth resistence is not found i.e. below 1.00 Ohms, the earthing shall be re-done by the Contractor at no extra cost.

IDENTIFIER/MARKER made out of mild steel plate of size 300mmx200 mmx4mm thick fixed by means of two Nos of rivets on mild steel strip of size 30mmx8mm thick and 70 cm long painted with synthetic enamel paint (except embeded portion) with following colour coding to identifier. (a) For chemical earth pits - Red Colour synthetic enamel paint shall be used (b) Lightning Arrester-LA (Oval Shape/ ) (c) Equipment Earth-EQ (Triangular Shape ) (d) Signal Earth-SG (Dome Shape) (e) Power Supply Earth-PS (Square Shape) NOTE:- (i) Height of the identifier should be 60 cm above the ground level all as specified. (ii) Quoted rate shall be deemed to included cost of PCC Block 1:3:6 using 40 mm graded stone aggregate size 45 cmx45 cmx20cm including necessary excavation and earth work and tarring of embedded portion. (iii) Writing letters shall be in block, painted with black colour synthetic enamel paint on plate and the size of writing letter on earth pit identifier shall not be less than 1 inch high (LA for lightning arrester earth pit, E for equipment earth pit, SG for Signal earth earth pit and PS for power supply earth pit) with total number of particular type of earthing (e..g. LA-1/4 means lightening arrester no. 1 out of total 4 LA for the building/equipment and so on) and Quoted rate shall be deemed to include the cost of writing letters..

Disconnecting and taking out old earthing including brick work, pit, pit cover, etc for site clearance complete all as specified and directed

RPS Tech Engineering (BID ID -3460357)

MUKTI ENTERPRISES (BID ID -3455353)

M/S NARAYAN ENTERPRISE (BID ID -3464614)