PROVN OF ISOLATION TRANSFORMERS AT VARIOUS LOCATIONS IN TECH AREA AT AF STN NAL

Amount

Excavation in trenches n. exc 1.5 metre wide and n exc 1.5 metre in depth for cable laying in any type of soil complete all as specified and directed.

Returning, filling in trenches including spreading, levelling, watering and well ramming in layers not exceeding 25 cm each complete all as specified and directed.

Removing excavated materials to a distance not exceeding 50 metre and depositing where directed at a level not exceeding 1.5 metre above the starting point complete all as specified and directed.

Material and labour for kolayat sand cushioning to under ground cables 8 cm thick before laying the cable and 15 cm, thick after laying, stretching and testing the cable complete all as specified and directed.

Material and labour for brick cover of old size bricks sub class 'B' with width equal to the length of the brick laid dry & flat abutted with each other with gap between adjacent bricks n.exc 10mm over UG cable for protection complete all as specified and directed.

Supply, laying & testing XLPE insulated armoured heavy duty electric cable with aluminium conductor 1100 Volts grade, cross sectional area 185 Sqmm 3.5 core in trench or fixed to wall/ passing through pipe/ pole complete all as specified and directed.

All as per item No 6.00 here in before but cross sectional area 50 Sqmm 3.5 core

All as per item No 6.00 here in before but cross sectional area 35 Sqmm 3.5 core complete all as specified and directed.

All as per item No 6.00 here in before but cross sectional area 25 Sqmm 4 core complete all as specified and directed.

All as per item No 6.00 here in before but cross sectional area 16 Sqmm 4 core complete all as specified and directed.

Supply, installtion, testing and commissioning of isolation transformer indoor type of capacity 200 KVA, 3 phase, 50 Hz, copper wound, oil cooled , class of insulation 'A', metalic body duly powder coated designed for input voltage range 415 + 5% and out put voltage range 415 + 5 % voltage, ratio 1:1 , vector group :Dyn 11, Delta-star type , IP 42 protection (CPRI approved) complete with over load protection, MCCB of suitable rating, first filling of transformer oil of requestic dielectric strength up to level , efficiencey more than 95%, seperate neutral bushing shall be brought out for earthing potential difference between neutral to earth less than one volt with all standard fitting like digital tempreture meter, adequate number of cooling radiators , lifting hooks, earthing terminal two nos as per IS complete with over load/short circuit protection. The isolation transformer shall produce a stable supply to the circuit and the connected equipments, The primary and secondary shall be made out of two electromagnets that are copper wound around each other in order to allow the primary coil to induce a current in the secondary coil. The isolation transformer can prevent the equipment connected to this from spikes and harmonics from the main. Efficiency should be more than 95%. Separate neutral bushing shall be brought out for earthing. Potential difference between N-E shall not be more than 1 Volt.

All as per item No 7.00 here in before but 150 KVA capacity complete all as specified and directed.

All as per item No 7.00 here in before but 50 KVA capacity complete all as specified and directed.

All as per item No 7.00 here in before but 20 KVA capacity complete all as specified and directed.

All as per item No 7.00 here in before but 15 KVA capacity complete all as specified and directed.

All as per item No 7.00 here in before but Out door type with IP -55 of capacity 125 KVA complete all as specified and directed.

All as per item No 7.00 here in before but Out door type with IP -55 of capacity 50 KVA complete all as specified and directed.

All as per item No 7.00 here in before but Out door type with IP -55 of capacity 20 KVA complete all as specified and directed.

Notes for Sl item No 7.00 to 7.07 (a)The rate quoted shall deem to include for connectoin with existing power sources cable lugs and glands and base channel as per manufacturer design. (b)Contractor shall obtain CPRI approval for IP42 protection in indoor type isolation transformers(Sl item No 7.00,7.01,7.02,7.03 & 7.04) and CPRI approval for IP55 protection in outdoor type isolation transformers(Sl item No 7.05,7.06 & 7.07).Nothing extra shall be paid to contractor on this account.

Material and labour for earthing complete with copper earth plate electrode 600mm x 600mm x 3.15mm thick, buried directly and preferably vertically in ground, earth pit not less than 3.65m deep below ground level with top edge of the plate not less than 2.90 m deep below ground level. The earth plate to be connected with copper earthing strip of size 32mm x 6mm thick by means of brashing between copper strip and earth plate minimum 45 cm in vertical length and copper strip also to be joined by brashing only. The copper earth strip to be protected by GI pipe 40mm bore medium grade upto ground level and there after with 40 mm HDPE pipe upto test point. Earthing shall be included with providing funnel with 20mm bore GI pipe light grade, wire mesh, charcoal or coke and common salt in alternative layer of 15 cm (compacted thickness) upto 90 cm all around earth plate further filled with 60 mm thick tibba sand and 2nd layer with 30mm magnesium sulphate powder (compact thickness), 3rd layer with tibba sand up to the ground level. Earthing shall also be included for providing concrete earth pit in PCC (1:3:6) type C1 (with 20mm graded aggregate), 50mm thick precast RCC (1:2:4) cover slab (reinforced with 8 mm dia. TMT bar @ 15 cm C/C both ways and suitable handle made of 10 mm dia.) including necessary earth work in excavation, returning filling, and removal of surplus earth up to a distance not exceeding 50 m etc. All as shown on electric plate No.3 of MES Schedule Part-I complete to obtain less than 1 ohm earth resistance value, complete all as specified and as directed. Note : The electric plate number given in specification is for guideline only for earth pit chamber. Colour coding and numbering for earth pit chamber also to be carried out under rate quoted by the contractor.

Supply and fix copper strip of size 25 x 3mm from test terminal point to Panel, DB etc as specified and directed with suitable insulators complete.

Supply and fix 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 specified and as directed.

Material and labour for PCC 1:4:8 type D2 using 40 mm graded stone aggregate as in foundation for isolation transformer, filling of mass concrete complete all as specified and as directed.

Material and labour for PCC 1:2:4 type B-1 using 20 mm graded stone aggregate as for staging of isolation transformer including form work complete all as specified and as directed.

Electro Tech Systems

Instruments and Equipment Co

R D Bansal

RAJENDER ENTERPRISES

RISING ELECTRICALS

M/s Chopra Associates

S.G.ENGINEERING COMPANY

MAHAVIR CONSTRUCTION CO