Construction Specification for Electrical Installations

 

1. Purpose
2. Scope
3. Related Documents
4. Location of Equipment
5. Fixing of Equipment
6. Provision of Cables
7. Cable Installation – General
8. Cable Support Systems
9. Cable Duct Systems
10. Buried Cable Systems
11. Filled Trench Systems
12. Cable Identification Labels
13. Surplus Cables
14. Cable Terminations
15. Conduit Systems
16. Distribution Boards
17. Local Control Pushbutton Stations
18. Junction Boxes
19. Socket Outlet Installation
20. Lighting Installation
21. Fire Alarm Installation
22. C.C.T.V., Telephones and Communication  System Installation
23. Earthing Installation
24. Weather Protection of Equipment
25. Labels and Nameplates
26. Protective Coatings
27. Testing of the Installation
28. Commissioning of the Installation

1. Purpose of this article is describe general requirements for electrical construction contracts.

2. Construction Specification for Electrical Installations

This technical specification generally applies to all Companies electrical construction contracts. In Construction Projects, When there is a conflict between the requirements stated in this specification and the project- specific Electrical Scope of Work, the Electrical Scope of Work shall take precedence.

3. Related Articles, International Codes and Standards

Painting and Corrosion Protection for Design Temperatures to 649°C (1200°F)

International Electrotechnical  Commission (IEC)

IEC 60529   Degrees of Protection Provided by Enclosures (IP Code)

International Organization for Standardization  (ISO)

ISO 8501-1   Preparation of Steel Substrates Before Application of Paints and Related Products – Visual Assessment of Surface Cleanliness – Part 1

4. LOCATION OF EQUIPMENT

  1. Structural levels shown on contract drawings are provided for guidance only. Equipment locations and cable installations shall follow the layouts shown on the contract drawings. Layouts shown are diagrammatic only and shall be subject to such minor changes as might be necessary to facilitate the installations, to coordinate the work with other crafts, or to overcome obstacles encountered during construction.
  2. When a major deviation from the contract drawings is indicated by practical considerations,  the contractor shall submit his proposals to the Company  representative in such detail as will clearly indicate the necessity or desirability of the change.
  3. When equipment locations are shown on the contract drawings as “to be determined on site,” the contractor shall apply to the Company  representative for detailed information regarding the location of the specific items of equipment.

5. FIXING OF EQUIPMENT

  1. All materials and equipment installed under this contract shall be firmly supported and secured. The contractor shall supply all fixings.
  2. Fixings to wood shall be by means of wood screws or bolts, to masonry by means of metal expansion bolts or screws and metal or plastic plugs (no wood or fibre plugs will be permitted), and to steel by means of nuts and bolts or beam clamps.
  3. The contractor shall repair and make good any damage, as a result of the contractor’s own installation work, to equipment or equipment finishes, other materials, or other installations.
  4. All steelwork and steel fixings, other than galvanised, supplied and installed by the contractor shall be painted by the contractor according to the Engineering Scope of Work documentation.

6. PROVISION OF CABLES

  1. The contractor shall supply all cables except when specifically excluded from his scope by the Scope of Work for Electrical Installations.
  2. The route lengths stated in the “Electrical Cable Schedule” are approximate only. The contractor shall survey and measure the actual route lengths on site before cutting any cable lengths from drums.
    • Claims will only be accepted for installation of cable lengths in excess of those stated in the “Electrical Cable Schedule” when the contractor can prove to the Company  representative that the route length stated is incorrect.
  3. An allowance of 3 metres at each end of each cable run has been included in the calculated length by Company . Claims for additional installed cable will not be accepted when they are due to wastage by the contractor (i.e., excessive lengths for cable termination having been pulled by the contractor). Any subsequent cable shortages caused by such wastage shall be to the contractor’s expense.

7. CABLE INSTALLATION  – GENERAL

  1. When cables rise otherwise unprotected from ground, foundation, mezzanine floors and platforms, the contractor shall fabricate and install protective steel plates, ducts or channels not less than 150 mm high, to shield the cables from mechanical damage.
  2. When power and control cables are run along parallel routes with instrumentation measurement cables, the instrument cables must be spaced at least 600 mm away from the other cables, or must be segregated from the other cables by means of continuous galvanised steel barrier plates.
  3. When holes are made in brickwork, concrete, or sheeting to allow access for cables, the contractor shall make good any damage, and seal such holes in the building fabric at no additional cost to the Company  representative.
    • Transit seals shall be used on all external building penetrations when located within hazardous areas or where internal segregation between areas has to be maintained. Cable entries to building located within nonhazardous areas shall be sealed with a waterproof fire retardant material to the satisfaction of the Company  representative. All cable duct entrances shall be sealed at the end of the installation contract, using waterproof and fire- retardant, expanded-foam-type sealants.
  4. Trays, conduit, and cable must not be routed across the panels of process vessel boxes or pipework transition structures but must follow stanchions and other main structural framework members. All fixings must be welded into position, with no holes drilled into box or transition steelwork.
    • Cable runs, trays, and conduits must be supported with a clearance of at least 150 mm from box and transition structures.
  5. The method of sealing cable entries into switchgear panels shall be agreed with the Company  representative before the work begins.

8. CABLE SUPPORT SYSTEMS

  1. The contractor shall erect all ladder/cable trays required by the contract drawings. All cable trays and tray support brackets shall be supplied by the contractor unless specifically stated to the contrary in the Scope of Work.
    • All fixings shall be provided by the contractor.
    • All ladder rack/cable trays shall be of the heavy-gauge, galvanised, perforated steel construction with return flange, irrespective of whether installation is indoor or outdoor. Tray support brackets shall also be of galvanised steel. The manufacturer and type of cable tray or cable ladder rack shall be as stated on the contract drawings. No substitutions shall be made unless approved in writing by the Company  representative.
  2. Cable trays must be adequately supported to prevent deformation under the cable load. When intervening supports are necessary between existing building and structural frame members, the contractor shall fabricate and erect suitable supports of steel channel or angle.
    • The contractor shall paint all channel and angle supports installed and shall also make good any paint work on existing steelwork to which new supports have been fixed.
    • A minimum of 150 mm space shall be provided between the tray and adjacent surfaces, to facilitate painting after installation work has been completed.
  3. All cables shall be secured to cable trays by means of approved, standard, plastic-covered metal or rigid plastic saddles, and plastic straps shall be spaced at frequent intervals with due regard to the mounting plane of the trays, so that the cables are firmly held in linear formation without buckling.
    • For securing large diameter cables individually, approved, standard, plastic-lined metal cable clamps may be used. The use of nylon tie-wraps is not acceptable as a means of permanently securing cables.
  4. When securing cables to trays by means of metal clamps or saddles, particular care shall be taken to avoid damaging the outer sheath of the cables. When cables approach or leave a cable tray through the tray itself, the hole shall be adequately bushed, again to prevent damage to the outer sheath of the cables.
    • When single core cables run aboveground, they shall be secured at regular intervals (not exceeding 3 metres), using proprietary trefoil cleats suitably rated for the cable short circuit capacity. Information regarding the cable short-circuit capacity will be provided by the Company  representative on the contract drawings.
  5. Cable trays supported on brackets fixed to structural steelwork shall normally be installed in the vertical plane.
  6. When cables are routed in trenches or pits with pipes and other services, adequate clearances (minimum 250 mm) must be maintained between the cables and other services. When cables cross other services, or groups of cables cross, fabricated steel crossover supports and cable trays shall be installed to carry the cables without sagging and with adequate clearances. When cable trays are installed in tier formation, adequate clearances must be maintained with regard to heat dissipation and future access.

9. CABLE DUCT SYSTEMS

  1. Before any cables are drawn into pipe ducts, ducts shall be rodded clean of all obstructing foreign matter.
  2. On completion of the installation of cables in ducts, the contractor shall make good any excavations dug to gain access to the ducts. The backfill shall generally be according to Section 10 of this specification.
  3. Unused duct openings shall be sealed with waterproof and fire-retardant, expanded-foam-  type sealants.

10. BURIED CABLE SYSTEMS

  1. When outdoor cables are buried directly in the ground, the contractor shall dig the trenches, lay the cables to the procedure specified, backfill, and make good the ground.
  2.  Before any excavation work for the cables begins, the cable routes shall be ranged and pegged out by the contractor and approved by the Company  representative.
    • When excavation work is performed in the vicinity of an existing operating plant, a permit to work must be obtained by the contractor from the Company  representative.
  3. The cables shall be laid in horizontal layers. The top surface of the largest cable in the top layer shall be a minimum of 750 mm below finished grade, and the burial depth shall not normally exceed 1500 mm.
  4. Having excavated the trenches, the cables shall be laid according to the following procedure:
    • The bottom of the trenches shall be covered to a depth of 100 mm by a bed of soft sand.
    • The cables shall be laid on the bed of sand, in linear formation, without unnecessary crossovers.
    • Each layer of cable shall be covered to a depth of 100 mm by a layer of soft sand well tamped down; sieved stone-free soil may be used for this purpose subject to the approval of the Company representative.
    • Protective cable tiles 50 mm thick shall be placed on top of the sand covering the top layer of cables. The tiles shall be of the fully interlocking pattern and shall be of the appropriate dimensions to give an overlap of 50 mm on either side of the span of cables covered.
    • The protective cable tiles shall be covered to a depth of 150 mm by a fine backfill of earth.
    • On top of the fine backfill, plastic cable warning tapes shall be laid along the whole of the cable routes in the trenches. The tapes shall be coloured bright yellow, with the phrase “DANGER – ELECTRIC CABLES” printed repetitively along the length of the tape (in both English and the local language).
    • Finally, the trenches shall be completely backfilled using sieved backfill and the ground made good to grade level. When the original finished surfaces have been disturbed, these shall be reinstated and consolidated to the original specification and to the satisfaction of the Company representative.
  5. The contractor shall install concrete surface marker posts along the routes of all buried cables, and the posts shall be fitted with permanent noncorrodible metal warning and identification plates inscribed as follows:
    • “DANGER – ELECTRIC CABLES” (in both English and the local language) Surface marker posts shall be installed at all points where cable routes change direction, and at maximum intervals of 20 metres along straight sections of routes.
  6. Direct-buried cables must be spaced at least 600 mm from underground pipes, whether crossing or following parallel routes. Where cables and pipes cross, in general the cables shall be laid above the pipes, provided that the cables can still be buried at a minimum depth of 750 mm below grade; if this minimum depth cannot be maintained, the cables shall be routed under the pipes.
  7. Underground joints must not be made on buried cables except when specified in the Scope of Work or when authorised by the Company  representative. When underground joints are permitted, special precautions shall be taken to avoid straining the cable joints, and the joint boxes shall be laid in the bottom of the trenches on precast concrete paving slabs approximately 1000 mm square x 50 mm thick.
  8. When direct-buried cable routes terminate under prefabricated buildings raised above grade on piers, the contractor may assume that the Civil Contractor will excavate underneath the building to a depth of approximately one metre below grade during the erection of the building foundation. The contractor shall perform any further excavations necessary to complete the cable trenching and to backfill the complete excavated area up to grade level after completion of the cable installation.

11. FILLED TRENCH SYSTEMS

Following are general instructions to installed filled trench system.

  1. When cables are run in concrete trenches within buildings other than substations or switchrooms, the cables shall be arranged in horizontal layers in sand in a similar fashion to that described for buried cable systems.
  2. The top layer of cables in the trench shall be a minimum of 250 mm below floor level, and they shall be covered with a layer of sand up to 50 mm below floor level. The trench shall be completed by a 50 mm thick top protective layer of weak-mix red screed to finish flush with finished floor level. Weak-mix red screed shall comprise 3 parts sand to 1 part cement with 1.5 kg red iron oxide per 50 kg sack of cement.

12. CABLE IDENTIFICATION  LABELS

Following are general methods to install cable identification or labels in electrical system.

  1. The contractor shall fit approved, permanent, strap-type cable identification labels (Critchely or equal) at both ends of all power and control cables installed (e.g., cable reference “101” must be marked “101”).
  2. The contractor shall also fit approved, permanent, printed-type sleeve ferrule cable identification labels at both ends of all cores of multi-core control cables installed; the cores shall be ferruled with appropriate wire number shown on the contract drawings. Split- or ring-type ferrules are not acceptable.
  3. The specific type of cable and ferrule numbering shall be agreed with the Company  representative before the work begins.

13. SURPLUS CABLES

  • On completion of the installation to the Company  representative’s satisfaction, the contractor shall seal at both ends, coil and label all usable surplus cable lengths remaining from those originally supplied by Company , and hand them over to the Company  representative.
  • All scrapped cable and unusable cable lengths shall be retained by the contractor, and the disposal arrangements agreed with the Company  representative.

14. CABLE TERMINATIONS

  1. Paper-insulated  cables shall be terminated using compound-filled  sealing boxes, or oil-filled or heat-shrinkable  plastic sealing ends, with glands and armour clamps, as appropriate to the types of cable involved and as specified on the contract drawings.
  2. High voltage, plastic-insulated  cables shall be terminated using stress-relieving termination kits together with compression-type  glands, with sheath seals and armour clamps, as appropriate to the types of cable involved and as specified on the contract drawings.
  3. Low voltage (below 1 kV), plastic-insulated  cables shall be terminated using mechanical-type  glands. The glands shall provide a compression seal over the inner sheath, and internal armour clamping cone and nut, and an additional clamping nut with neoprene washer over the outer sheath for weatherproofing.  Glands shall be of brass and shall be complete with earth tags. For cables with aluminium armour, compatible cable glands must be used (i.e., aluminium alloy.)
    1. M.I.C.C.-type cable shall be terminated using compression-type  glands with screw-on seals.
    2. Plastic gland shrouds shall be fitted to all glands in outdoor locations.
  4. All cable terminations shall be made according to recognised standard practice, as recommended by the cable manufacturers. The responsibility for provision of termination materials shall be as specified on the contract drawings.
    • All control cable terminations of 1.5 mm2 or below shall have, as a minimum, “boot lace”-type insulated ferrules. All conductors above this size shall be terminated using pin or blade-type, crimped, insulated terminations, as a minimum.
  5. When certified crimping lugs are available, the conductor ends of power cables shall be crimped to cable lugs. This method shall be used for solid aluminium and stranded-copper  or aluminium conductors requiring lug-type terminations. Long-barrel, double-hex-type  crimping lugs shall be used for all HV terminations and shall be used for LV terminations whenever possible.
    • When sector-shaped, solid aluminium conductors are to be connected to clamp-type terminals, the conductor ends shall be swaged and fitted with brass sleeves. All sleeves shall be provided by the contractor.
    • All cable lugs shall be supplied by the contractor. Insulated lugs shall be used whenever possible. When insulated lugs are not available, all terminations shall be insulated using high- temperature, electrical insulating tape or heat-shrink sleeving.
  6. The correct sizes and types of cable lug must be used for conductors of all cables so terminated, and the correct crimping tools used. Cable conductor strands must not be reduced in number, or solid conductors reduced in cross-sectional  area, when the conductors are terminated in cable lugs or clamp-type terminals.
  7. For multicore cables with metallic armouring and/or earth conductors, the metallic armouring and/or earth conductor must be properly bonded at both ends of each cable to the cable gland, terminal box (if applicable), and equipment frame. For single core cables with metallic armouring, and/or screen, the metallic armour and/or screen must be bonded at the field end only, unless otherwise indicated in the contract drawings.
  8. The contractor shall ensure that only trades persons who are fully skilled and properly qualified in the appropriate techniques are permitted to terminate cables. The contractor shall also ensure that the trades persons are fully equipped with the proper tools appropriate to the types of cable to be terminated.
  9. When paper or high-voltage, plastic-insulated  cables are used and are to be terminated in cable sealing boxes, the electrical equipment will normally be supplied by the Company  representative, complete with cable sealing boxes, glands and armour clamps, but the contractor shall supply the appropriate type of sealing compounds.
  10. When paper-insulated  cables are used and are to be terminated in oil-filled or heat- shrinkable-plastic  sealing ends, or when plastic-insulated  cables are used and are to be terminated in cast-resin sealing ends, the electrical equipment will normally be supplied by the Company  representative, complete with cable terminal boxes, glands and armour clamps, but the contractor shall supply the appropriate type of sealing end.
  11. Medium voltage (above 1 kV) equipment, provided by the Company  representative, will normally be supplied with undrilled gland plates. The contractor shall drill gland plates as necessary and fit all cable glands required.
  12. All spare cores shall be terminated and earthed unless shown otherwise on contract drawings.
  13. The contractor shall ensure that magnetic loops are not created around single core cables.
  14. Cable joints are not permitted without the express written permission of the Company  representative. Such joints shall be made using Raychem or 3M Scotchcast termination kits or an approved equivalent. Current-carry capacity of cable armour and continuity of cable screens shall be maintained across all joints.

15. CONDUIT SYSTEMS

  1. The contractor shall supply and erect all electrical conduit (with associated adapters and accessories) necessary for lighting, small power, and local control wiring installations, as shown on the contract drawings. All conduit shall be steel, heavy-duty gauge, welded and shall have a galvanised finish.
  2. Conduits must be adequately supported to prevent deformation and sagging. The contractor shall fabricate and erect suitable intervening conduit supports of steel angle between existing building and structural members for surface conduits, if necessary, in a similar manner to that described in paragraph 8.2.
  3. All surface conduits shall be firmly secured to support structures by means of galvanized-steel  spacer bar saddles.
  4. Conduit systems shall be designed and installed with adequate provision for draining off condensed moisture and water ingress at all low points on conduit runs.
  5. All conduit fittings shall be screw-type, malleable iron and shall have a galvanised finish. Inspection fittings shall not be used and all junction boxes shall be fitted with purpose-made gaskets of rubber, neoprene, or equal.
  6. Adequate “draw box” fittings shall be incorporated in conduit runs to permit easy removal or insertion of wiring after initial installation.
  7. When cables emerge from conduit lengths on noncontinuous runs, the ends of the conduit shall be fitted with screwed bushes, to prevent damage to the cable insulation.
  8. When flexible conduits are used, the watertight, plastic-sheathed-metallic-type shall be installed. The ends of flexible conduits shall be fitted with standard brass adapters specifically designed for this purpose. External earth continuity conductors shall be fitted to all flexible conduits.
  9. In continuous conduit systems, only single-core, plastic-insulated  cables shall be used. In noncontinuous conduit systems, only multicore, plastic-insulated,  and sheathed cables shall be used.
  10. Cable sizes and numbers of cables in specific conduits shall be according to the ratings defined in applicable national standards and codes.

16. DISTRIBUTION  BOARDS

  • The contractor shall erect all distribution panel boards specified on the contract drawings; the supply of the distribution boards shall be as specified in the Scope of Work.
  • Distribution panel boards shall be surface-mounted-type with metal-clad enclosures for indoor or outdoor locations as specified in the Scope of Work.

17. LOCAL CONTROL PUSHBUTTON STATIONS

  1. The contractor shall supply and erect all local control stations specified on the contract drawings.
  2. Local control stations shall be the surface mounted type with enclosure protection to IP55 minimum according to IEC 60529. The control stations shall be suitable for outdoor location (irrespective of whether they are to be mounted indoors or outdoors). The type and manufacturer shall be as stated on the contract drawings.

18. JUNCTION BOXES

  1. The contractor shall supply and erect all cable and wiring junction boxes, complete with terminals, specified on the contract drawings.
  2. Junction boxes shall be the surface mounted type with enclosure protection to IP55 minimum according to IEC 60529. The junction boxes shall be either metal-clad or high-impact plastic/polycarbonate enclosures suitable for outdoor location (irrespective of whether they are to be mounted indoors or outdoors).
  3. Terminal boxes shall incorporate fully-shrouded, screw-clamp terminals, with serrated pressure plates for secure conductor fixing.

19. SOCKET OUTLET INSTALLATION

  1. The contractor shall erect all utility socket outlets as specified on the contract drawings. Socket outlets shall be part of Company  supply unless stated to the contrary in the Scope of Work.
  2. The contractor shall supply and hand over to the Company  representative one plug of the appropriate type for each socket outlet installed by the contractor.

20. LIGHTING INSTALLATION

  1. The contractor shall erect all internal and external lighting equipment specified on the contract drawings; this shall include all lighting fittings, switches, and accessories. All fittings shall be provided by the contractor.
  2. The required types and enclosure protection classifications of lighting equipment shall be as specified on the contract drawings.
  3. All lighting fittings shall be securely fixed to structures or purpose-made supports. Chain or other flexible supports shall not be used on any part of the installation.

 21. FIRE ALARM INSTALLATION

  1. The contractor shall supply and erect all equipment required for the complete fire alarm scheme specified on the contract drawings, unless otherwise stated in the Scope of Work.
  2. The required types and enclosure protection classification of fire system components shall be as specified on the contract drawings.

22. C.T.V., TELEPHONES  AND COMMUNICATION SYSTEM INSTALLATION

The contractor shall supply and erect equipment for the telephone and communication system installation specified on the contract drawings. This might include provision of empty conduits, or wiring, or equipment, and will be specifically defined in each instance.

23. EARTHING INSTALLATION

  1. The contractor shall install all cables for earthing of equipment in this installation, as specified on the contract drawings. All fittings shall be provided by the contractor. All fittings and installation materials shall be nonferrous.
  2. For clarity of presentation of the contract drawings, minor earth loops and bonding have not been shown on the earthing cable schedule.
    • The contractor shall, however, supply and install the complete earthing installation to meet the following requirements:
      • Company ‘ standard practice is to earth low voltage equipment supplied from a switchboard motor control centre or distribution board by means of the supply cable armouring. When this practice is not permissible because of specific national regulations, alternative philosophies shall be as stated in the Scope of Work for Electrical Installation.
      • In all cases, earthing conductors shall be located so that the conductor providing the earth current return path from any item of equipment to the system-earthed-neutral is run in the same duct bank, cable trench, or cable tray as the phase conductors that feed that item of equipment.
      • The combined resistance of the electrodes provided for the main earthing system shall not exceed 1 ohm when measured to the general mass of earth.
      • The earthing installation shall comply with the current issue of the national wiring regulations for electrical installations. Attention is drawn to the requirements for maximum earth loop impedance and disconnection times for fixed and portable equipment.
    • When a project is an extension to an existing plant and the new earthing system is to be solidly bonded to the existing system, the contractor shall seek guidance from the engineer as the maximum value of the new system to the general mass of earth. The contractor shall ensure that the measurement reflects the new system only and is independent of the existing installation.
  3. Supplementary bonding of electrical and nonelectrical equipment, vessels, tanks, and structures:
    • The metallic enclosures of electrical distribution equipment, nonelectrical equipment, vessels, tanks, and structures shall be bonded and earthed by connection to the common earthing grid or be provided with their own electrodes.
      • When an earthing conductor has to run over a concrete foundation, 25 x 3 mm copper tape and associated clips shall be utilised so as not to form a trip hazard.
      • Pipelines shall not be used for earthing purposes.
      • The cross-sectional area of branch conductors connecting equipment and structures to the switchboard or earth rod shall be (unless indicated to the contrary on the contract drawings):
      • –     to metallic enclosures of LV electrical distribution equipment having a supply cable with a conductor cross section of less than 35 mm2, use 35 mm2.
      • –     to metallic enclosure of LV electrical distribution equipment having a supply cable with a conductor cross section of 35 mm2 and more, use 70 mm2.
      • –     to structures, tanks, process plant equipment and other nonelectrical equipment shall be performed using an earthing conductor with a cross section of 35 mm2.
      • Note:  The earth grid conductors comprising main earth ring conductors and branch conductors shall be considered as supplementary to the protective earth conductors or to the metallic sheath and/or armouring or other metallic covering of the electrical equipment supply cable(s).
    • Lightning and static electricity
      • For protection against lightning and the accumulation of static charges by means of a low impedance lightning discharge path to earth, earth electrodes shall be located near the base of elevated structures requiring lightning protection. The electrode(s) shall be connected to the structure to be protected and to the main earth grid by conductors of 70 mm2 cross sectional area.
      • The combined resistance-to-earth of the electrodes provided for lightning protection shall not exceed 7 ohms when isolated from the structure to be protected and the main earth grid.
    • Instrument earthing
      • Special attention shall be paid to the earthing of the instrument computer and control systems. Earthing shall be performed by connection to a copper earth busbar mounted on insulators in the DCS/Analyser building. This instrument earthing busbar shall be connected by 35 mm2 insulated copper conductors to the substation earth busbar at two points only, or as specified in the contract drawings.
      • The combined resistance of the electrodes provided for the instrument earthing system shall not exceed 5 ohm when measured to the general mass of earth.
  4. Earth conductors shall be installed in one length between connection points, when possible.
  5. Screw-type, solderless conductors or similar mechanical connectors shall not be used underground. If splices or taps are required on underground runs, they shall be made by the thermoweld process and adequately insulated to prevent corrosion occurring.
  6. All conductor connections to structures and equipment shall be made aboveground, by screw- type, solderless connectors.
  7. When earthing connections are to be made to items of process equipment, such connection shall only be attached to support rings or other equipment support structures; no connection shall be made to surfaces of process equipment or to cover plates of vessel boxes or pipework transitions.

24. WEATHER PROTECTION OF EQUIPMENT

Unless otherwise stated in this document or the Scope of Work, all equipment provided by the contractor for installation outside buildings shall be completely weatherproof to IEC 60529 (IP54 minimum). When necessary to comply with IP54, additional weatherproof covers shall be supplied and installed by the contractor, at his own expense.

25. LABELS AND NAMEPLATES

  1. The contractor shall supply and fix a permanent Traffolyte label (Dymo tape or similar labels are not acceptable) to each junction box, contactor unit, distribution board, isolating switch, and control station. Labels shall have black lettering on a white background.
  2. Isolating switches shall be labeled with the equipment reference of the associated equipment. Control stations shall be labeled according to the contract drawings.
  3. Labels shall be in both English and the local language and shall identify the equipment duty and tag number.
  4. Labels shall be affixed by means other than adhesive.

26. PROTECTIVE COATINGS

Galvanizing

  1. All steelwork supplied and installed by the contractor shall be hot-dip galvanised.
  2. Damaged or cut galvanised surface shall be repaired according to the following procedure (the use of Galvafroid or similar treatments is not permitted):
    • The affected areas shall be power wire brushed or manually prepared to a minimum of ST3 standard, as defined in ISO 8501-1, ensuring that the damaged galvanised area is feathered back to a sound edge.
    • The prepared area shall then be painted with 75–100 µm of a Two-pack Zinc Rich Organic Primer.

Painting

  1. The contractor shall make good any damage to paint work or protective finishes caused to any equipment or structure by his installation.
  2. The contractor shall touch up any paint work required to electrical equipment installed by the contractor under this contract, in particular enclosures mounted outdoors.
  3. Painting shall be done according to 4WEQ-6804. Company  will define in the project- specific “Electrical Installation – Scope of Work” specification which painting specification applies.

27. TESTING OF ELECTRICAL INSTALLATION

  1. The contractor shall test the complete installation. The extent of the testing shall be such as to ensure that each part of the installation is in a suitable state to permit energization without causing electrical or mechanical damage, and is ready for operational testing.
  2. The contractor shall provide all test equipment necessary to perform all the testing required.
  3. The contractor shall perform the following work associated with the testing:
    • Prepare a schedule of proposed testing methods. The schedule, test sheets, and inspection forms must be approved by the Company representative before commencement  of testing.
    • Carry out all testing detailed as below.
    • Prepare a handwritten copy of test results for the Company representative.  The results shall be handed to the Company  representative at the conclusion of each test.
    • Prepare formal test reports for final distribution to the Company representative.
    • Maintain a log of all testing and inspections performed.
  4. Before any piece of electrical equipment is energized or put into operation, the contractor shall perform all tests necessary to confirm that the equipment is correctly installed, that all wiring is correctly carried out, and that the equipment is in a satisfactory condition for operation.
    • The Company  representative reserves the right to witness all tests and the contractor shall give the engineer a minimum of 48 hours prior notice of all tests to be performed.
  5. A dc high-voltage test shall be made, after installation, on metal-sheathed  or plastic-sheathed  cables in the following services:
    • All cables, except motor feeder cables, operating at system nominal voltage higher than 690 volts.
    • All motor feeder cables operating at system nominal voltage of 2,400 volts or higher.
  6. The dc high-voltage tests shall be performed according to the following:
    • Cables shall be fully terminated and then disconnected from equipment before performing high voltage testing to prevent motors, switchgear, and transformers being subjected to the test voltage.
    • The test voltage, duration of test, and test procedure shall be according to the national standard to which the cable conforms.
  7. Winding-insulation  resistance of power transformers shall be measured at 500 Vdc between primary and earth, secondary and earth, and between primary and secondary.
  8. Before switchgear is energised, the following tests shall be made:
    • Insulation resistance of each bus shall be measured at 1000 Vdc from phase-to-phase and from phase-to-earth. Measurements shall be made with all circuit breakers in the operating position, but with contacts open.
    • An ac, high-voltage test shall be made on the busbar systems and circuit breakers. The test voltage, duration of test, and test procedure shall be according to the manufacturer’s commissioning instructions.
    • Test 27.8.1 shall be repeated after completion of Test 27.8.2.
    • Before switchgear is energised, the insulation resistance of all external control cabling shall be measured at 500 Vdc between cores and to earth as appropriate.
  9. Before being energised, every circuit shall have its insulation resistance measured at 500 Vdc between phases and between each phase and earth. The insulation resistance of the circuits listed below shall be measured as follows:
    • Motor feeders: Insulation resistance measured from load side of contactors or circuit breakers and with motors disconnected.
    • Motor control circuits: Insulation resistance of cabling external to the switchboard measured with all field pushbuttons connected.
    • Lighting feeders: Insulation resistance measured with feeder circuit breakers, fuse switches, contactors, lighting transformers and distribution boards connected, but with all subcircuit switches or circuit breakers open.
    • Lighting final subcircuits: Insulation resistance measured after all lamp holders, lighting fittings, socket outlets are connected, but before lamps are fitted. Some circuits with ballasts might only require measurement to earth.
  10. The insulation resistance of all motor windings shall be measured at 500 Vdc before power cables are connected to the motors. Measurements shall be repeated after power cable terminations are completed.
  11. Conductivity (ductor) tests shall be performed on all LV and HV busbar systems.
  12. The resistance-to-earth shall be measured at each earth electrode and at sufficient points on the earthing system to ensure that the values of resistance to earth specified on the contract drawings are not exceeded.
  13. The contractor shall submit to the Company  representative, for approval, copies of the proposed test sheets and handover documentation.

28. COMMISSIONING  OF THE INSTALLATION

  1. This section covers commissioning of all equipment forming part of the installation shown on all contract drawings.
  2. The Company  representative will commission all equipment with the exception of the lighting and small power, and trace heating systems.
  3. The contractor shall commission the lighting and small power, trace heating, and fire alarm systems.
  4. The contractor shall provide, when requested, suitably experienced specialist labour to assist, under the direction and supervision of the Company  representative, in the commissioning of any items of equipment that the Company  representative requires.
  5. The contractor shall provide a systematic package of signed test sheets with each item of equipment such that the equipment can be commissioned as a complete system (i.e., motor, power cable, control cable, pushbutton station, earthing, and motor starter).

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