SUKPHURIC ACID AND CONCENTRATION PLANT AT
ARUVANKADU, TAMIL NADU
Page 1 of 11
Ann 1/1
- INSTALLATION, TESTING & COMMISSIONING OF CABLES
GENERAL
Installation of cables shall generally include the following types of cables:-
i)1100V grade aluminium conductor, PVC insulated, armoured power cables
ii)1100V grade copper conductor, PVC insulated, PVC sheathed armoured control and instrument cables
In the plant buildings. MCC rooms/ Control room power and control cables shall generally taken exposed on brackets, cable racks/ cable trays laid in built-in cable ducts, concrete cable trenches or along building and technological structures.
In the auxiliary shops and utility building power and control/ instrument cables shall generally taken on cable racks/ trays either laid in concrete trenches or supported from building structures, walls/ ceiling etc. Power and control / instrument cables along buildings and technological structures, ceiling, walls, floors etc. which are required to be protected against mechanical damage shall be taken in G.S. conduits.
Cables in trays shall be clamped at not more than 1500 mm for horizontal and 800mm for vertical run. While cleating on wall/ structure GI saddles with cleats shall be used.
All cable risers irrespective of type of installation shall be protected by means of GS pipes to a height of 2 metre from the working floor level. Entry or exit of cables from underground trenches or cable ducts shall be through pipe sleeves. Pipe sleeves shall be properly sealed.
Cable runs shall be uniformly spaced, properly supported and protected in approved manner. The bending radius of various cables as per IS 1255 shall not be less than 12 x diameter of cables.
Power and Control /Instrument cables shall be laid in separate racks/ cable trays.
All cables shall be provided with identification tags including cable numbers in accordance with the cable / circuit schedule. Tags shall be fixed at both at entry and exit ends of the cable. The tags shall be of aluminium sheets with the numbers punched on them and securely attached to the cables with non-corrosive wire. Individual cores of control / instrument cables shall have, for identification, plastic ferrules with engraved numbers at both ends of the circuit.
All cables shall be terminated at both ends through heavy duty type nickel brass cable glands. Crimping type cable lugs shall be used for termination of power cables and Control/ Instrument cables. In some cases the control cables may be directly terminated at terminal blocks by screws.
All cable racks/ trays, supporting brackets and cabling accessories shall be painted with two coats of red oxide primers and one coat of synthetic enamel paint.
Power cables laid directly buried in ground shall be laid as per requirement of code of practice IS:1255. Generally cables shall be taken at a depth of 900mm from GL and shall be provided with 75mm sand cushioning both at top and bottom and pre-cast protective cover. All control and instrument cables shall be laid in cable trays in shop floor along wall / cable duct. Outside the building the control and instrument cables shall be laid in overhead cable tray. Control cables can be laid in bunches. Power and control cables shall be in separate cable trays. Suitable size Hume pipes shall be provided at road crossing/ drain crossing etc.
All cables (power, control & instrument) run inside the SAC plant shall be laid on cable tray made from FRP material.
Power cable of each motor shall be terminated to a power JB of adequate ratings terminal block. From the PJB cables shall be terminated to motor through flexible copper cables through flexible GI pipes.
In each cable run, both at exit and entry point some extra cable length shall be kept for future maintenance etc.
While laying cables parallel to buildings, utility pipe lines, drainage etc., the minimum clearance shall not be less than one metre.
SUPPLY OF MATERIALS
Cable Glands – Cable glands shall be tinned brass heavy duty type, complete with necessary armouring and tapered washers.
Cable lugs – Crimping type aluminium lugs for power cables with aluminium conductor and tinned copper lugs shall be used for control , instruments and signal cables.
Cable trays – cable trays shall be pre-fabricated ladder type galvanized steel of 2mm thickness. Cable trays shall be complete with all accessories such as ground continuity connections, bimetallic nuts, bolts, washers, hangers, clamps, tees and bends.
Supports – All supports, hangers and brackets shall be manufactured from steel. Wherever necessary these shall be supplied and fabricated at site.
Cable termination and jointing kits – Supply all materials for cable termination and jointing kits for power cables, control and instrument cables.
SCHEDULE OF WORK IN GENERAL
sl.no. / item description / qty01. / laying of aramoured aluminium conductor power cable in cable tray/ duct, in cable trenches, along wall in plant from mcc to different motors of following sizes:
- 3cx4
- 3cx6
- 3cx16
- 3 ½ c x 95
- 3 ½ x 300
1000 m
400 m
150 m
150 m
02. / laying of aramoured copper conductor cotrol cable in cable tray/ duct, on overhead cable tray, along wall in plant from plc to different different instrumenys / panels of following sizes:
- 7c x 1.5
03. / laying of aramoured copper conductor instrument cable in cable tray/ duct, on overhead cable tray, along wall in plant from plc to different instrumenys / panels of following sizes:
- 3cx1.5
- 9c x 1.5
1500 m
04. / supply & erection cable tray made from 2mm thick ms sheet, hot dip galvanised finish complete with slotted rung @250 mm in each 2500 mm length of cable tray. The tray shall be complete with galvanised coupler plates, nuts, bolts and washers. Sizes of cable trays –
150 mm width
300 mm width
600 mm width / 200 m
200m
150m
05. / supply & erection covered cable tray made from frp material, & shall be complete with fixing materials as required -
150 mm width
300 mm width
600 mm width / 300m
200m
40m
06. / erection of metal clad local control station on wall or structure with required fixing materials (lcs shall be supplied by epl) / 25 nos.
item description / qty
07. / erection metal clad control / instrument junction box on wall or structure with required fixing materials. the jb shall be supplied as free issue item. / 15 nos.
08. / termination of pvc armoured cables including supply & fixing heavy duty compression type cable gland complete with nickel coated brass gland, rubber rings for dust & moisture proof entry of pvc armoured cables, crimping type copper lugs/ sockets etc., as required, as per following sizes –
a)3cx 4
b)3cx6
c)3cx16
d)3 ½ cx 95
e)3 ½ c x 150
f)7c x 1.5
g)3c x 1.5 / a)10 no.
b)30 no.
c)16 no.
d)6 no.
e)6 no.
f)30 no.
g)35 no.
09. / making of cable trench for laying of underground cables of size
- 1500 width x 900 depth
- 450 width x 900 depth
100 m
10. / Erection of overhead cable tray structure and supplying and fixing cable tray of size 300mm from SAC building to chillar plant and to Boiler House / 10 m
11. / supply and erection of a mcb db on wall / structure having 63a TP switch fuse units at incomer, 63a 3 phase alu bus bar and 9 nos. 6a tp mcb, 10ka at outgoing for power supply to exhaust fans. The db shall have removable cable glands at bottom for cable entry. / 1 no.
12. / laying of cables 3cx4 from the mcbdb to the exhaust fan motors including termination by cable glands at both ends. cables shall provided by epi. / 180 m
13. / supply and erection of heavy exhaust fan complete with motor, impeller, mounting ring, ms arms and rubber suspension pieces, strictly confirming to is 2312 with ip 55 & acid proof at sac building / 8 nos.
Ann 1/2
- INSTALLATION OF SYSTEM AND EQUIPMENT EARTHING
The method adopted for system as well as equipment earthing shall be in accordance with Code of Practice for earthing IS 3043. It shall also comply with the relevant clauses of Indian Electricity Rules. The earthing shall in general as per the Earthing Layout drawings.
The earthing installation shall be complete in all respects and shall include supply of materials like GS Flat, GI wires, earth electrode, all materials for construction of earth pits, weatherproofing compound, steel saddles, clamps, bolts, washers etc as required. Where earth conductors are buried underground the excavation and subsequent backfilling shall be done by the contractor.
All non-current carrying metallic parts of various electrical equipment as well as cable armouring, metallic pipes, cable trays etc. shall be effectively earthed. Earthing of medium voltage equipment shall be done by means of two separate earth continuity conductors connected either directly to earth electrodes or to the nearest earthing ring main. However low voltage equipment may have single earthing. Main earth rings and earth riser/leads shall be directly buried in ground. Additional earthing rings, connected to at least at two separate connections to the underground main ring, shall be provided over ground inside plant buildings. Earth continuity conductors shall be taken from this ring for connection to earth of various equipment, cable trays, structures etc. The details of main earthing ring main , earth risers, earth pits etc have been shown in the drawings.
Earth continuity conductor embedded in concrete shall generally follow the shortest route and wherever possible shall be taken along pipes embedded for laying of cables. MS saddles shall be used for clamping earth conductors on cable trays. Structures, walls etc. The saddles shall be clamped to stell flat spacers with tapped holes.
The earthing electrodes shall be at least 1.2 to1.5 metre away from building. The erection of earth stations shall include the necessary excavation, construction of a masonary enclosure with top cover, connections, provision of homogeneous mixer of charcoal. Sand and salt and shall be in accordance with drawing and instruction. Each earth electrode shall also be provided with a marker. The contractor after installation shall test the earth resistance so as to obtain combine grid resistance less than one ohm. If, require, the contractor may increase number of earth pits to obtain the require result. For details earthing system please refer to Earthing Layout in Main Boiler House and Chillar Plant, vide drawing nos. CFSP-528-PCS-ETL-A-009-A1-SH 1 OF 1- R-00 & CFSP-528-PCS-ETL-A-010-A1-SH 1 OF 1- R-00.
EQUIPMENT EARTHING IN SAC PLANT
Earthing materials which shall be used inside the SAC Plant shall be of non-ferrous alloy and shall be preferably of insulated copper wire. Earthing of the plant outside the building shall be done by GI, but all equipment earthing and over ground earthing conductor shall be done by PVC insulated flexible copper wire. For details earthing system please refer to Earthing Layout in Main SAC Building, drawing no. CFSP-528-PCS-ETL-A-011-A1-SH 1 OF 1- R-01.
ELECRONIC EARTHING – Separate earthing system shall be provided for the electronic control system and associated power devices as per electronic equipment manufacturer’s recommendation. Electronic earth pits shall be connected with electronic equipment through 35 sq.mm single core stranded flexible copper wire laid in GI conduit. The flexible copper wire shall be connected to copper plate of size 320 x 320 x 6mm buried in the electronic earth pit 3 metre depth. Number of earth pits to be constructed shall be as per the manufacturer’s recommendation.
SCHEDULE OF WORK FOR POWER EARTHING
Sl. No. / Item description / Quantity1) / supply & erection earth electrode with 100mm nb x 3000mm long perforated (40 nos.10mm dia holes) gi pipe driven to a depth of 3m below ( -)1.25m level and shall be surrounded by homogeneous layer of coke, charcoal & salt. The work also include construction of a masonary enclosure on top of above earth electrode of size 650 x 650 x 400 mm deep below ground level complete with cemented brick work (1:6), duly plastered with cement morter(inside), CI hinged inspection cover, 65 mm dia pvc conduit as per our said drawing. / 12 sets
2) / supply & erection of main ground grid conductor of 50 x 6 mm gi flat around each building, burried at a depth of 1000mm below grade level and a distance between 1200 & 2000 mm from the building structure / 700 metre
3) / supply & erection of overground conductor (earth bus) of size 50 x 6 mm gi flat around the perimeter of the inside wall of the boiler house & chillar plant at a height of 600mm above f.f.l , having clearence of 6mm from wall including providing suitable number drilled holes on the earth bus complete with gi bolts, nuts, washers, spacing insulators etc. as required. / 100 meter
4) / supply & erection of earth overground conductor of pvc insulated flexible copper wire of size 70mm2 around the perimeter of the inside wall of each floor of the sulphuric acid & concemtration plant (sac) building on suitable saddles and connecting 25 x 6 x 300 mm long copper earth bus bars. the earth bars shall be provided at least three numbers in each wall and shall be interconnected to the earthing system. / 200 metre
5) / connecting the equipment to overground earth bus including s/f gi flat / gi wire/ pvc insulated flexible wire (applicable in sac plant only), on wall, burried inside wall / floor as required, and making connections to equipment with bolts, nuts, washers, copper lugs, sockets etc. and mending good damages.
50 x 6 gi flat
25 x 3 gi flat
no. 8 swg gi wire
6 mm2 pvc insulated cu wire / 100 metre
150 metre
500 metre
250 metre
SCHEDULE OF WORK FOR ELECTRONIC EARTHING
Sl. No. / Item description / Quantity1) / supply & erection earth electrode of copper earth plate 600 x 600 x 6 mm thick driven to a depth of 3m below grade level, 25mm dia x 2500 mm long copper tube through 80nb gi pipe x 2200 mm long, connecting the copper tube with the earth electrode by brazing and connections to earth riser / conductor of 70 mm2 multi strand pvc insulated copper cable through fexible pvc conduit , and shall be surrounded by homogeneous layer of coke, charcoal & salt. The work also include construction of a masonary enclosure on top of above earth electrode of size 650 x 650 x 400 mm deep below ground level complete with cemented brick work (1:6), duly plastered with cement morter(inside), ci hinged inspection cover. / 4 sets
2) / Supply and laying of 70 mm2 size pvc insulated single core flexible copper wire through flexible pvc pipe from each earth electrode to earth bus at plc control room / 100 metre
3) / supply and fixing 50x6 x400 mm long copper bus bar, having suitabel number of drilled holes for connections of earth conductor. / 2 nos.
4) / Supply and laying of single core 6 mm2 size pvc insulated single core flexible copper wire through flexible pvc pipe from eath bus bar to plc control panel and othe instruments etc / 60 metre
- INSTALLATION OF LIGHTNING PROTECTION SYSTEM
The installation of lightning protection system shall be carried out strictly as per IS 2309 – Code of practice of building and allied structures against lightning. It shall comprise of installation of roof conductors, down conductors, earthing stations and associated accessories. The lightning protection system shall be in general in accordance with Lightning Protection of buildings drawings.
The lightning protection system shall comprise of air terminations, in the form of horizontal conductors, air terminals, test links and earth electrodes. The installation shall be carried out as shown in the aforesaid drawings. Earthing system and lightning protection system shall be electrically interconnected.
Air terminations shall be of horizontal conductor type. The horizontal air terminations shall be so interconnected that no part of the roof is more than 9 metre away from the nearest horizontal conductors. For flat roof horizontal conductors shall generally be provided along the outer periphery of the roof. All metallic projections, chimneys, ducts, vent pipes etc. on or above the main surface of the roof shall be properly boded to the air termination network.
The number of down conductors from air termination to the earth electrode shall be selected on the basis of one down conductor for every thirty metre of building perimeter. However, in no case the number shall be less than two. Down conductors shall follow most direct path possible between air termination and earth electrode through a suitable TEST LINK.
Installation of galvanized strips directly buried in ground shall be inclusive of excavation of trench, laying and welding of the strips and back-filling of the trench with shifted soil.
Installation of GS strips along building roofs comprising CGS sheet or concrete walls, columns, structures shall include necessary cutting of holes, making chess, clamping, bolting, welding etc. It shall also include the supply of necessary clamps, nuts, bolts, MS washers, bituminous washers, weatherproofing compound, paint etc. to make the installation complete in all respects. Holes and damages done to the existing civil and structural work shall be repaired. All welded and bolted joints and steel strips shall be painted with anti corrosive paint.
Installation of earthing stations shall include excavation of earth pit, installation of earth electrode, supply of salt & charcoal, wherever required, backfilling of the pit making a slopping 300 angle etc. The earthing station shall include supply and installation of Test Link comprising 250mm long, 50 x 6 mm galavanised strip having required number of holes with nuts and bolts for connecting the down conductor to the earthing station in accordance with said drawings.
SCHEDULE OF WORK FOR LIGHTNING PROTECTION SYSTEM
Sl. No. / Item description / Quantity1) / supply & erection earth electrode with 40mm dia x 3m long ms rod driven to a depth of 3m below grade level with suitable gi clamps with gi bolts & nuts for connection to the dpwn conductor. / 7 nos.
2) / Supply & fixing gi testing link of size 50 x 6 x 250 mm long having suitable drilled holes for fixing the 50 x 6 mm down conductor and the 50 x 6 mm riser. the test link shall be fixed on wall / structure having clearence of 6mm from wall for making connections of the gi flats / 7 nos.
3) / Supply & erection lightning air terminal of 20mm dia x 1000mm long medium GI pipe having five discharge prong of 4 swg gi wire at top with a 6 mm thick base plate duly fixed at the roof top and connected to directly to the earth electrode through the down conductor / 7 nos.
4) / Supply & fixing of 5ox6mm gi flat for down conductor along the steel structure member by properly fixing with structure by welding and final connection to the test link. the down conductor shall be suitably and welded to the horizontal conductor along the roof of the structure. also supply & fixing of horizontal roof conductor of 50 x 6 mm on the roof, saddles 1100 mm apart including connections/ welded to the the down conductor / 250 metre
Ann 1/3