Electrical Installations
AA REQ 565005DISCIPLINE REQUIREMENTS ELECTRICAL
INSTALLATIONSISSUE 023 March 2011
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AA REQ 565005DISCIPLINE REQUIREMENTS ELECTRICAL
INSTALLATIONSISSUE 011 April 2011 COPYRIGHT
DISCIPLINE REQUIREMENTS ELECTRICAL INSTALLATIONS
CONTENTSPage1Scope42Regulations43Technical Requirements as
Specified by the Engineer44Definitions45Portable Electrical
Appliances and tools55.1Earth Leakage Units55.2Flexible Cables and
Cords55.3Power Supplied by the Company See Special Conditions of
Contract56Excavation of Cable Trenches and Installation of Cables
in Trenches66.1Cable Routing and Clearance to Excavate66.2Location
of Trench66.3Method of Excavation66.4Risk of Collapse to Sides of
Excavations66.5Keeping Excavations Free of Water66.6Excavation
Depth and Arrangement of Cables66.7Marking of Cable Routes, Cable
Markers76.8Material Classification77Installation of Cables not in
Trenches87.1Cables Crossing Roads87.2Cable in Tunnels87.3Cables in
Ducts87.4Cables Passing Through Concrete Floors of
Foundations87.5Cable Installation on Racks or Trays97.6General
Cable Handling107.7Cable Joints107.8Terminations107.9Sealing of
Cables117.10Labelling of Cables117.11Cable Glands (Unless Specified
in the Bill of Quantities)118Installation of Equipment118.1Motor
Control Centres118.2LV Motors128.3MV Switchboards128.4Mini
Substations128.5Distribution Transformers128.6General138.7Light
Fittings138.8Light Fittings and Socket Outlets in Substations and
Control Rooms148.9Protection of Equipment After
Erection149Earthing149.1Substations149.2Cables159.3Welding
Machines159.4General169.5Lightning
Protection1610Conduit1610.1General1610.2Surface Conduit
Installations1711Welding1711.1General1711.2Electrodes1811.3Corrosion
Protection, Painting & Patching1812Method of Fixing Rack and
Other Support Steelwork1812.1Welding1812.2Use of Hilti
Studs1812.3Bolts, Nuts and Washers1812.4Unistrut1812.5Holes Drilled
in Structural Steel1813Testing and
Energising1913.1General1913.2Specific Tests Required1913.3Pressure
Testing of MV Cables1913.4LV Cables (Up to 1kV)1913.5MV
Switchgear2013.6LV Distribution Switchgear and Motor Control
Gear2013.7Transformers2013.8Field Equipment2013.9Test
Equipment2113.10Tests on Equipment Using Test Voltages Exceeding
1kV2113.11Test Certificates2113.12Checking the Completed
Installation2113.13Commissioning and Energising of
Equipment2214Acceptance of Work22Appendix A: Referenced
documents23Appendix B: Record of Amendments23Appendix C: Site Test
Certificate - Motors24APPENDIX D: SITE TEST CERTIFICATE - MOTOR
CONTROL CENTRES25APPENDIX E: SITE TEST CERTIFICATE
TRANSFORMERS26
ScopeThis document covers the Electrical Installations in
Surface Plants excluding Overhead Lines and should be read in
conjunction with the Bill of Quantities or the Contractors Scope of
Work.It defines the standards of materials and equipment,
installation work and ancillary work to be employed in the
electrical installation contract or sub contract.
RegulationsAll Installations shall comply with the relevant
sections of the following:Minerals Act and Regulations applicable
to region.Occupational Safety and Health Act or equivalent
regulations applicable to region.
Technical Requirements as Specified by the EngineerIEC
62305-3:The protection of structures against Lightning
IEC 62305-5-54:The design and installation of Earth
Electrodes.
IEC 62305-1:The protection of Dwelling Houses against
Lightning.
IEC 60364:Low Voltage Electrical Installations
Definitions
QAR:Quality Assurance Authority; An independent inspection
agency appointed and approved by the Engineer
IEC:International Electro-technical Commission
Non- metallic enclosures/ polycarbonate enclosures:An enclosure
or housing made from any non-metallic substance such as
Polycarbonate, PVC, glass fibre, reinforced plastic (GRP), or
others which are ultra-violet light resistant, corrosion resistant,
impact resistant and deemed to be suitable for the duty
envisaged.
Hazardous areas:Any Hazardous area classification on the Plant
or works shall be specified to the Contractor in writing, or
specified in the Bill of Quantities or the Contractors Scope of
Work.
Stainless steel:Unless otherwise indicated the term stainless
steel will mean grade 316 stainless steel.
XPLE:Cross Linked Polyethylene
The following terms are defined in the Conditions of Contract:
Anglo American, Approved, Company, Contractor, Engineer.
Portable Electrical Appliances and tools
Earth Leakage UnitsAll electrical appliances and tools, working
off 110 or 230 volt supply, shall be protected by an earth leakage
unit of 30 milliamp sensitivity, either of a portable or fixed
type.All 400 Volt feeders for portable equipment shall be protected
by an instantaneous operating earth leakage unit of not greater
than 250 milliamp sensitivity.Note: Welding Socket Outlets to be
equipped with a separate circuit breaker c/w 30mA earth leakage
unit for personnel protection.
Flexible Cables and CordsAll flexible cables and cords must have
a separate continuous earth core.No joints are allowed in these
cables.All cables must be fitted with an approved plug, suitably
rated.The termination of cables on plugs must be done by a
qualified electrician.Damaged plugs, cords or cables are not to be
used.The user of cables or cords is held responsible to report any
damage or noticeable defect to the Foreman electrician
concerned.Repairs to electrical cords, cables and plugs may only be
done by a qualified electrician.Note: when double insulated
portable tools are used, clause 5.2 bullet 1 does not apply.All
electrical tools where possible shall be of the double insulated
type and must be to the approval of the Engineer.
Power Supplied by the Company See Special Conditions of
ContractWhere the company supplies the contractor with power the
contractor must report to the Engineer prior to commencing work on
the Plant.The Engineer will arrange point/s of supply and
inspection of the contractor's equipment.Note: the engineer
reserves the right to discontinue power supply if in his opinion
any equipment is unsafe or does not meet the conditions stipulated
in this specification.
Excavation of Cable Trenches and Installation of Cables in
Trenches
Cable Routing and Clearance to ExcavateNo excavation is to be
commenced in an existing installation until authorisation has been
given by the Engineer who will provide the Contractor with details
of existing buried services in the area concerned.No installation
should commence until such confirmation of the route has been
obtained from the Engineer.Where obstructions are encountered which
necessitate diversions of cables due to adjacent structures, pipes,
drains, etc. approval of such deviations shall be obtained from the
Engineer.The runs shall be selected to avoid exposure to drip or
accumulation of liquids or high temperatures.
Location of TrenchThe exact location of each trench is to be
approved by the Engineer.
Method of ExcavationThe use of mechanical excavation machines
will only be permitted when written approval has been given to this
effect by the Engineer.
Risk of Collapse to Sides of ExcavationsAny trench of a greater
depth than 1.5 metres, or where ground conditions require, is to
have the side walls adequately shored up.All precautions are to be
taken to ensure that damage resulting from subsidence will not
occur adjacent to roads, railways, walls, sewers, drains, pipes or
similar structures.
Keeping Excavations Free of WaterThe excavations shall be
protected from flooding, and any water which occurs in the
excavations whether as a result of seepage, rain or other causes
shall immediately be removed by baling, pumping or other approved
method, ensuring that damage does not occur to cables.
Excavation Depth and Arrangement of CablesDepth of Cable
TrenchesMinimum 600mm for low voltage cables and 900mm for medium
voltage cables.
Width of Cable TrenchesThe minimum width of the trench to be
500mm.Trenching ConfigurationTrenches are to be straight, cut
square and the bottom of a trench is to be level and free from
stones or hard projections.The bottom of the trench is to be
covered by a layer of fine sifted soil, at least 50mm thick, before
any cables are laid. Laying of Cables in TrenchesCables shall be
laid such that a minimum gap of 25mm is maintained between the
outside edges of all cables. Covering In of CablesCables shall be
covered with a layer of fine stone-free soil not less than 75mm
thick. Thereafter the following procedure is to be followed:Medium
and low voltage cablesThe trench is to be filled in with local
soil. The soil is to be firmly stamped down. Any surplus soil is to
be piled on top of the trench. One month later, any subsidence must
be made good and the trench levelled off.
Marking of Cable Routes, Cable MarkersA PVC cable warning marker
tape is to be installed in each trench running the complete length
of the trench and be laid 300mm above the cables.Concrete cable
markers are to be placed at a maximum of 50 metre spacings along
the entire length of the cable trench/route and at every change in
direction of the cable.
Material ClassificationThe removal and disposal of all materials
encountered while carrying out excavation shall be included in one
of the classifications of excavation as described in the Bill of
Quantities or the Contractors Scope of Work.The decision of the
Engineer as to the classification of the material shall be final
and binding, and any objections as to the classification must be
made in writing before the excavations have been backfilled.
Installation of Cables not in Trenches
Cables Crossing RoadsCables are to cross roads via one of the
following methods, as indicated on the drawings:Cable tunnels with
reinforced roofs and sturdy wallsCulverts, where the cables are in
ducts.Culverts or reinforced concrete pipes with a minimum diameter
of 150mm where cables are laid directly into the ground.NOTE: Where
reinforced concrete pipes are used, a separate pipe is to be used
for each individual cable having a bitumen jute serving (outer
sheath).Suitable pipe sleeves made from steel or PVC with a minimum
diameter of 110mm.NOTE: The Engineer will specify the number of
cables per sleeve.On large diameter cables, only one per sleeve
will be allowed.Analogue and telephone cables are to be in sleeves
separate to electrical cables.After cables have been installed,
each sleeve is to be sealed with a suitable material approved by
the Engineer.
Cable in TunnelsCables shall be installed on racks along the
sidewalls of the cable tunnel.
Cables in DuctsCables are to be neatly laid parallel to each
other. The position of high, medium and low voltage cables is to be
approved by the Engineer.Entrance of cables into the duct from the
side shall be through a sleeve of adequate size (inside diameter of
the sleeve is to be at least twice the outside diameter of the
cable).After the cable has been installed, the sleeve is to be
sealed with a suitable material approved by the Engineer.
Cables Passing Through Concrete Floors of FoundationsWhere
cables pass through a concrete floor or foundation, etc., they will
be passed through galvanised steel or high density PVC pipe that is
at least 50mm larger than the cable diameter.In the case of floors,
this pipe will extend from 60mm below to 360mm above the slab.NOTE:
Not more than one long radius bend of up to 90 degrees may be used
in any unbroken pipeline.The maximum overall length of such pipe
section is not to exceed 30 metres. The minimum radius of a 90
degree bend shall be 15 times the cable outside diameter.
Cable Installation on Racks or TraysWherever possible, racks are
to be mounted in the vertical plane.Racks to be adequately
supported to carry the overall weight of the maximum number of
cables for which such rack is designed.Racks are to be supported at
every point where the route of the rack changes direction.Single
angle iron cable supports may be used under the following
conditions:not more than 2 cables per single angle ironthe angle
iron shall be of adequate dimensions to support and protect the
cable/sWhere cables are exposed and mechanical protection is
warranted, a solid sheet metal cover shall be bolted into position.
Power and control cables may be run on a common rack, providing
they are separated and/or identifiable to the approval of the
Engineer.Cables are to be clamped or strapped in separate voltage
groups.A maximum of three cables may be bulk clamped or strapped
providing they are of similar diameter.Spacing of cable clamps on
cable racks must not exceed:OVERALL CABLE DIA. mm.MAX.SPACING -
HORIZONTALMAX.SPACING -VERTICAL
Not exceeding 15mm.350mm450mm
15 - 22mm400mm525mm
22 - 32mm450mm600mm
Exceeding 32mm500mm700mm
NOTE: Vertical in the above table means a cable rack rising at
90 degrees to the horizontal.Horizontal means a rack running in the
horizontal plane, with the rack mounted such that it is vertical or
edgewise.Individual cables may be installed in galvanised conduit
secured with saddles. Spacing shall be such as to maintain the
cable in a straight line.Cable strapsUV stabilised PVC straps will
be allowed. Heavier cables (> 25mm 4 core) will be strapped
using stainless steel straps.
General Cable HandlingCables are to be laid in trenches or fixed
on racks directly off the drum.Cables of long lengths shall be
pulled with a cable stocking or pulling eye and pulled over cable
rollers and corner rollers.Under no circumstances shall cable be
pulled whilst in contact with the ground.In pulling cables, the
manufacturer's specifications regarding the pulling force, bending
radius etc. shall be observed. Suitable drum jacks are to be
provided.Cables are to be transported around site on the cable
drums provided by the cable manufacturer and on a custom built
cable drum trailer and haulage vehicle.
Cable JointsType of joints to be used on:1. Low voltage cables
(up to 1kV)Approved standard stock, cast type joint boxes or
moulded resin joints are to be used.The armouring to be carried
through externally on cast joint boxes and internally with moulded
resin joints.1. MV Cables above 1kV not exceeding 52kVOnly
appropriate approved jointing kits shall be used.1. ConnectionsAll
cables are to be hexagonal crimped.1. PhasingColour-to-colour or
number-to-number connections must be maintained throughout the
length of cables.
TerminationsWhere cable cores are connected to stud type
terminals, crimp-on lugs are to be used. Only appropriate approved
medium voltage stud type connection insulation to be used for type
C bushings, and where applicable, only appropriate approved putty
to be used.M V Cable TerminationsOnly appropriate approved
termination kits to be used on MV cables.Mini-substations,
Transformer M.V. terminal boxes and MV SwitchgearOnly appropriate
approved heat shrink-terminations to be used for crutch and cable
tails in the terminal boxes of these units such as Raychem,
Sigmaform, or 3M unless other terminating systems e.g. "DYSCON" or
similar are being used.
Sealing of CablesCable ends shall be sealed immediately they
have been cut. A lead seal end cap or PVC `heat shrink' end cap may
be used.
Labelling of CablesAll cable cores shall be fitted with the
correct marking ferrules as detailed on cable schedule and
inter-connection diagrams.Every cable shall have a stainless steel
"DYMO" type tape attached on each end on which shall be punched the
cable number shown on the cable schedule.NOTE: As built cable
schedules are part of the Special Conditions of Contract.
Cable Glands (Unless Specified in the Bill of Quantities)Indoor
Areas, MCC Rooms and SubstationsOnly appropriate approved cable
glands shall be used.Outdoor AreasOnly appropriate approved
anti-corrosion type cable glands shall be used such as CCG
corrosion guard type - no shroud.Hazardous AreasGlands to be used
in such areas will be specified in the Bill of Quantities or the
Contractors Scope of Work.
Installation of Equipment
Motor Control CentresMCC's are to be installed by the contractor
only if specified in the Bill of Quantities or the Contractors
Scope of Work.The tiers are to be handled with care and installed
in the correct sequence as shown on the General Arrangement
drawings.Any damage to the doors or equipment on the MCC's is to be
reported to the Engineer as soon as possible.
MCC's will be tested in accordance with the Site Certificate -
Motor Control Centres, attached to this specification. See also
paragraph 13.6.Warning notices must be erected on energised
circuits during commissioning.All wires connected to terminals must
have enough slack to allow for remaking the terminations.
LV MotorsLV motors will be installed by others, but the
contractor shall make the electrical connections. Cables are to be
connected to the terminal box via a specified or approved gland.
Motors to which 4 core cables are being used will have the 4th core
terminated to the earth inside the terminal box. Where a separate
external earth conductor is being used this will be bolted
externally to the motor frame. All connections shall be made with
compression lugs. Cable boxes on motors are to be drilled for cable
entries and no burning of holes will be permitted.LV Motors will be
tested in accordance with the Site Certificate - Motors, attached
to this specification.
MV SwitchboardsNormally the manufacturer of any MV switchboards
will install them.In certain circumstances, the Installation
Contractor may be requested to install this equipment. This will be
set out in the Contractors Scope of Work.Under no circumstances
shall any MV switchboard be energised by the contractor without the
permission of the Engineer and the approved inspection and test
report by the manufacturer or representative.The installation shall
comply with the appropriate Code of Practice and Testing Code of
Practice.
Mini SubstationsAre to be installed complete including
connecting MV and LV cable with specified termination kits and
glands, neutral bushing to earth, transformer body to earth,
auxiliary wiring to protective devices, neutral to earth CT for
earth leakage protection, and installing dehydrating breather and
padlock to transformer bay and warning boards when the transformer
is energised.
Distribution TransformersAre to be installed complete including
connecting MV and LV cable with specified termination kits and
glands, neutral bushing to earth, transformer body to earth,
auxiliary wiring to protective devices, neutral to earth CT for
earth leakage protection, and installing dehydrating breather and
padlock to transformer bay and warning boards when the transformer
is energised. A thorough check shall be carried out by the
Contractor to ensure all associated loosely transported parts of
equipment has been installed ie. breather, conservator etc. An oil
sample shall be taken and sent for testing for any ingress of
moisture, if requested by the Engineer.
GeneralAll equipment shall be installed as per the
manufacturer's instructions and to the approval of the Engineer.All
equipment shall be carefully levelled and adjusted for
operation.Precautions shall be taken to counter vibrations likely
to be transmitted by plant machinery. As vibrations are unlikely to
be fully evident until machinery is operating, checks for
vibrations shall be made during commissioning.Any unsatisfactory
conditions detected shall be reported in writing to the Engineer
for remedial action.Equipment shall not be grouted in position
prior to inspection and approval by the Engineer.Neither compressed
air nor cotton waste shall be used for cleaning
purposes.Distribution boards and control boards which are wall
mounted shall have horizontal centre lines approximately 1 500mm
above floor level.All equipment is to be protected throughout
erection against the ingress of moisture, dust, dirt and foreign
bodies.Equipment to be stored shall be given adequate covering. The
contractor shall be responsible for any damage or loss of goods
handed over to him and he will be required to replace, free of
charge, any damaged or lost items.Light switches, socket, power and
plug outlets shall be installed as indicated on the relevant
drawings. Where it is not practical to mount the equipment as
shown, amended instructions will be issued by the Engineer.Mounting
heights of all other equipment will depend on the circumstances but
will also be subject to the written approval of the
Engineer.Multi-phase outlets shall be connected in accordance with
the plant's standard rotation.Bare earth wires shall have a Heat
Shrink covering at the terminals.A clearance of 2m or better shall
be left between switches or socket outlets and water taps.
Light FittingsAll light fittings shall be installed in
accordance with project drawings. However, due care and attention
should be given to accessibility for maintenance and lamp
replacement. All fittings shall be complete with lamp of correct
size and type.Floodlights shall be orientated at night and then
securely clamped, to ensure a uniform distribution of light over
the area to be illuminated.Where suitable terminals are not
provided within fittings the contractor shall provide suitable
connectors.In general, all fittings should be fixed directly onto
steelwork by means of suitable support brackets. The design to be
approved by the Engineer if not detailed in the project
drawings.Light fittings to have a minimum 3 way junction box
associated with each. Connection to fitting, if suspended, to be
flexible. Any unused gland holes to be fitted with stoppers. The
Contractor must take particular care that the I.P. rating of any
fitting is maintained during installation.Fittings installed in
Hazardous Areas will have the correctly specified Cable Glands, and
the contractor must ensure that the manufacturer's installation
instructions are adhered to.The Engineer shall be notified in
writing of the date on which lighting circuits are energised and
the fittings in a particular plant area are put into service. The
fitting and lamp guarantee period shall commence from this date.
This date shall be recorded in writing by the contractor and agreed
by the Engineer. This date will not necessarily be deemed to be a
hand-over.
Light Fittings and Socket Outlets in Substations and Control
RoomsWhen the Installation Contractor is requested to install
lighting and socket outlets in substations and Control Rooms, the
Contractor is to obtain from the Engineer an indication of the
standard that will be required. This will normally be via
drawings.These will indicate whether surface mounted conduit with
wiring will be required, and specify whether PVC or metal conduit
is to be used, as well as the colour in the case of PVC conduit.The
Contractor may be required to phase the fittings.These items are to
be agreed before the work is commenced.
Protection of Equipment after ErectionIt will be the
responsibility of the contractor to ensure that all equipment
erected by him is protected against accidental damage that could be
caused by other ongoing erection activities of all disciplines.The
contractor will therefore be called upon, to make good and damage
caused to equipment due to lack of adequate precautions being
taken, as described above with any costs being for his account.
Earthing
SubstationsStandard details will normally be shown on drawings
and may include the following:Earthing rods or an earthing mat is
to be installed as per the design drawings.
Branch tee-offs from the main earthing conductor to the earth
mats, transformer star points and bonding of equipment are to
be:brazed in the case of solid to solid conductor connectionsonly
appropriate approved methods shall be used in the case of stranded
to solid conductor connections such as exothermic welds, PG clamps
or lugsAll cable trays, racking, conduit, trunking, cable sheaths
and armouring, substation screens and all other metal work
connected with wiring (other than the current carrying parts) are
to be bonded to earth.The Contractor is to ensure that a suitable
earth is provided. This shall be by use of a suitable
specification, or notification that an earthing specialist is to be
used.Overall impedance of less than 5 ohms to the general mass of
earth should be obtained.
Cablesa) Armoured cables (LV below 1000V)The armouring is to be
bonded to earth using mechanical compression glands to clamp the
armouring at each end of the cable.NOTE. Single core armoured
cables will have the armouring bonded to earth at one side of the
cable only. This will normally be done at the sending end. b)
Cables and motors and other up to 1kV equipmentMotors that have 4
core cables with the 4th core being used for earthing, shall in
addition have the armouring made off in the usual manner.In this
case the earthed core shall always be the "black" conductor. c) MV
cables (XLPE)Armouring is to be made off in normal manner using
suitable gland. Separate 70mm green PVC sheathed conductor from
substation or switchgear earth bar to the item of equipment is to
be installed in addition.
Welding MachinesThe earth leads of all welding machines must be
of equal length to the electrode lead.The earth lead must be
clamped directly to the material being welded.Proper joint couplers
must be used for joints in welding leads. No joint consisting of
lugs, bolted together and taped-up are permitted.1kV primary cable
to be of the flexible trailing cable type, with each phase core
individually screened.
GeneralFor 3 phase 3 wire installations where 4 core cable has
been specified, the fourth core (black) shall be used as the earth
conductor.On 3 phase 4 wire installations, the fourth core (black)
shall be used as the neutral conductor with a separate suitably
rated bare copper conductor used as the earth conductor.NOTE: in
certain cases green PVC sheathed conductor may be specified as the
earth conductor.NOTE: Bare earth conductors buried in the ground
shall be kept at least 600mm from buried cables unless the cables
are PVC sheathed overall. Insulated earth conductors are
recommended where stray D.C. traction currents or soil conditions
could cause electrolytic corrosion.All steel structures shall be
bonded and earthed against static charges, in accordance with the
drawings.Main earthing points shall be made of a suitable number of
copper earth rods, driven to a suitable depth. Earth mats or plates
shall be as specified by the Engineer.When the armour of a cable is
earthed, the clamp used shall be of special design so that it will
grip firmly and permanently without damage to the insulation or to
the sheath of the cable.Where an earthing conductor is exposed to
possible mechanical damage, it shall be protected by means of a
suitable conduit or pipe, preferably non-metallic.Where earthing is
carried out in acidic areas, all earth conductors shall be PVC
insulated. The neutral point of all lighting transformers shall be
earthed directly to the earth system by means of insulated
conductors of the same cross sectional areas as the power
cable.
Lightning ProtectionBuildings and metal structuresTo provide for
lightning protection the contractor will install earth electrodes
at the corners of buildings and metal structures. All structures
must be so earthed at 2 opposite corners and at intervals of not
more than 50 metres. The steel cladding and metal structures are
then bonded to the earth electrode unless otherwise detailed on
drawings.All down conductors installed within touching distance of
personnel, shall be insulated to prevent accidental electrical
shock.
Conduit
GeneralThe conduit shall have a minimum diameter of 20mm and be
cut square and clean before threading. Threads shall be made using
suitable conduit thread dies and the liberal application of cutting
grease or similar. The length of thread shall be such as to permit
conduits to be firmly butted together in couplings and hard against
the shoulders of threaded conduit box spouts with no thread
exposed.The ends of all cut lengths of conduit shall be reamed free
from burrs and any loose swarf shall be removed from inside the
conduit.Sockets, bends and fittings shall be of the same material
as the conduit.
Surface Conduit InstallationsAll surface run conduits shall be
of the galvanised type unless otherwise specified in the Bill of
Quantities or the Contractors Scope of Work. Conduit runs on the
surface of walls, floors, ceilings, or in accessible ceiling voids,
etc., shall be installed in a neat manner running generally with
the building lines. The conduits shall be vertically plumb and
horizontally level as applicable. Bends in multiple runs of conduit
shall be matching. Other right angle bends shall be standard
machine made. In all instances the installation shall present a
neat and workmanlike appearance.Where open-ended conduit is used to
support lighting cables, the ends shall be bushed.Fixings of tubing
shall be affected by spacer bar saddles. Light gauge saddles may be
used for general internal installations whilst heavy base saddles
are to be used for external galvanised conduit installations and
industrial applications.
Welding
GeneralWelding shall comply with the requirements of IEC
60050-851, Welding.Before any welding is carried out on an existing
structure, the properties of the steel shall be determined.All
welding shall be done by qualified welders who have been previously
qualified by test in accordance with the requirements of IEC
60050-851 - Welding and the contractor shall submit evidence of
such qualifications to the Engineer if called upon to do so. An
operator shall require re-qualification if he has not been engaged
in metal welding for a period of three months or more, or when
changing type of material, or if there is a specific reason to
question the welder's ability.All welding shall be by the electric
arc process unless oxyacetylene welding is specified.The welding
plant return clamp is to be at all times connected directly to the
item being welded, to prevent damage to any equipment by stray
return currents.The Engineer may direct the contractor to remove
any inferior welding and/or direct the contractor to cut test
specimens from the welds which, in the Engineer's opinion, are of
inferior quality. The Engineer may direct that welds be nick broken
or bent in his presence. Alternatively the contractor may provide
x-ray or other approved non-destructive tests on suspect welds with
all test methods being subject to the prior approval of the
Engineer.
ElectrodesElectrodes shall be selected so that the resulting
weld is compatible with the design requirements with respect to
both strength and ductability.
Corrosion Protection, Painting & PatchingRefer to
specification issued for the Project in the Bill of Quantities or
the Contractors Scope of Work.
Method of Fixing Rack and Other Support Steelwork
WeldingWhen welding as a method of fixing rack and support
brackets and steelwork onto existing steelwork is prohibited, this
shall be indicated to the Contractor in the Scope of Work. In such
cases, all support steelwork requires to be attached to existing
steelwork using the drill and bolt method.When welding as a method
of fixing rack is allowed, the Contractor shall ensure that the
specifications for priming, patching, and painting of steelwork,
and any other corrosion control prevention methods required, are
properly executed.
Use of Hilti StudsThis type of fixing may be permitted when
welding is not allowed.The contractor will be required to enforce
all the necessary safety precautions that are required by the
Engineer and as laid down by the Minerals Act or the OSH Act
applicable to region.
Bolts, Nuts and WashersSpecified areas are to be stainless
steel.Non-specified areas to be galvanised.
UnistrutAll Unistrut to be hot dip galvanised No stainless steel
need be used
Holes Drilled in Structural SteelNo holes shall be drilled
without approval of the Structural Engineer. Any holes drilled are
to be made good as detailed in the Painting and Corrosion
Specification.
Testing and Energising
GeneralThe contractor shall be responsible, as part of his scope
of work, to carry out testing and pre-energisation checking of
electrical equipment in accordance with methods and procedures laid
down hereunder.The Contractor shall appoint a competent person to
control all testing and checking activities. This person shall
report to and liaise closely with the Engineer in order that
testing activities may be conducted and sequenced in a manner best
suited to the commissioning programme.Defects revealed during
testing and checking which are attributable to the contractor shall
be made good by the contractor without delay.Where defects in
free-issue supplied equipment are revealed, these should be
reported to the Engineer at an early date.
Specific Tests RequiredTesting of electrical equipment shall
include, but not be limited, to the following:Testing of MV cables,
joints and terminations using the cable manufacturers
recommendation, this will vary depending on the type of cable i.e.
XLPE or PILC.Insulation testing of up to 1kV power cables using a
2000V hand wound Insulation Tester.Continuity test and phasing out
of all cablesPre-energisation testing of transformers.Testing of LV
Distribution Switchgear and Motor Control Centres.Testing and
measuring of substation earth.Proving correct mechanical operation
of moving parts e.g. relays, limit switches, switch or contactor
mechanisms, timing devices etc.Spinning of motors to determine
correct direction, and recording of no-load and load
information.
Pressure Testing of MV CablesEach MV cable shall be tested after
installation and before it is energised. Tests shall be carried out
after all terminations and joints have been completed. The AC and
DC test voltages will be as per the cable manufacturer's
recommendations for such tests.
LV Cables (Up to 1kV)All LV cables shall be tested for
insulation resistance before installation and after termination
(before connecting to apparatus) using a 2 000V DC insulation
resistance tester. Insulation resistance values of less than
200megohms before installation shall be suspect and
investigated.The end-to-end DC resistance of cores of buried cables
shall be measured and recorded in a test certificate.
MV SwitchgearAfter erection, ensure all protection settings have
been checked via primary and secondary injection tests. Refer AA
Standard STD 543013 Testing and Inspection of Medium Voltage
Electrical Equipment.
LV Distribution Switchgear and Motor Control GearAfter erection,
all LV distribution switchboards and motor control centres shall be
tested for insulation resistance using a 2000V DC insulation
resistance tester.Phase to phase and phase to earth insulation
resistance values of under 50megohms shall be suspect and
investigated.All motor protection devices shall be set at 100% of
motor full load current.Check that all isolation and lockout
equipment including interlocking tests have been carried out.
TransformersThe MV winding of transformers shall be tested to
earth using a suitable insulation resistance tester and the LV
winding using a 2000V DC insulation resistance tester. Insulation
resistance values of under 500megohms and 200megohms for the HV and
LV windings respectively shall be suspect and
investigated.Dielectric Loss (Tan Delta / Power Factor) and Swept
Frequency Response Analysis tests to be carried out if required by
the Engineer. Buchholz relays shall be tested by air or Nitrogen
injection. Nitrogen would be preferred.Temperature relays, if
fitted, shall be tested by checking the operation of alarm and trip
contacts. The contacts are to be set at the alarm and trip values
as required by the Engineer.Silica gel breathers shall be oil
sealed to the required level and checked for dryness.
Field EquipmentAll field equipment shall be checked in respect
of mechanical operation of all moving parts, tightness of
connection.Testing shall be repeated each time an installation is
disturbed e.g. carrying out of a cable joint.Leakage currents shall
be recorded on the test certificate.
The contractor shall ensure safety of personnel during testing
operations and this shall include the stationing of a person at the
remote end of the cable under test. He shall also ensure that the
cable is properly discharged before authorising workmen to proceed
with termination work.Testing shall be carried out with the cable
in its final position except for the individual cores on each
termination, which shall be moved away from their respective
connection points.Precautions shall be taken to ensure that the
main busbars do not become energised during the testing
operations.
Test EquipmentThe contractor shall make available suitable
staff, tools and testing equipment, including necessary AC and DC
pressure test sets, earth testers, multimetres and clip on type
ammeters. Other specialised test equipment that may be required
will be provided at an agreed rate in accordance with Special
Conditions of Contract at the request of the Engineer.
Tests on Equipment Using Test Voltages Exceeding 1kVThe Engineer
will be responsible for authorising the Contractor to carry out
these tests. Any safety precautions as laid down or requested by
the Engineer must be adhered to.
Test CertificatesAfter completion of the tests detailed above,
the contractor shall complete a test certificate showing the
results of the test.Appendices to this specification give details
of the Project requirements in terms of test certificate
format.Completed test certificates shall be handed to the Engineer
within seven days of the test. Failure to do so may result in
rejection of the test data in which case the contractor would be
required to repeat the tests concerned at his expense.
Checking the Completed InstallationAfter each respective
installation has been completed, the installation shall be
thoroughly checked, by the contractor, against the appropriate test
certificate detailed in this specification.Checking shall be
carried out before testing commences.Submission of the completed
check sheet, to the Engineer, shall indicate that the installation
detailed on the respective check sheet/s is complete and ready for
inspection and `punch listing' by the Engineer.
Commissioning and Energising of EquipmentPre-commissioning
checks, energisation and commissioning of all electrical equipment,
other than lighting circuits, shall be the responsibility of the
Engineer or his deputy.It is probable that the Engineer will, from
time to time, require assistance from the contractor. Upon request
therefore, the contractor shall make available, on a day work
basis, suitable qualified staff to assist the Engineer with
commissioning activities.Motor rotationAfter energising of MCC's,
motor will be "bumped" for direction testing. Any motors or other
equipment that require direction changes will have two phases
swapped at the motor terminal box by the contractor.Defects Found
During CommissioningAny defects found by the Engineer during the
commissioning shall be rectified by the contractor except where the
defect is as a result of faulty manufacture by the supplier of the
equipment free-issued to the Contractor and providing that the
defect is not as a result of damage occurring during installation
by the Contractor.Defects found during commissioning on equipment
supplied by the Contractor shall be repaired by the Contractor as
quickly as possible.Where it is decided by the Engineer to request
the contractor to repair or make good a manufacturing defect the
cost of such repairs shall be agreed and written up onto a site
instruction before the work is commenced.
Acceptance of WorkThe Contractor is to seek acceptance in
reasonably small packages, to avoid duplication of undesirable
practices as rectified work is costly in time and money.The
Contractor shall utilise the test certificates in preparing work
for acceptance and the schedule of rates shall include for any
costs involved.Acceptance of work which will eventually be buried
or concealed is to be sought at uncovered stages.At the completion
of each package, the Contractor shall provide an acceptance
certificate for signature by the Engineer.
Appendix A: Referenced documentsAA_REQ_565005, Discipline
Requirements Electrical RequirementsThe latest issue of the
following documents shall form part of this Requirement:
IEC 62305-3:The protection against lightning
IEC 62305-5-54:Electrical installations of buildings
IEC 62305-1:The protection of Dwelling Houses against
Lightning
IEC 60364Low-voltage electrical installations
IEC 60050-851:International Electro-technical Vocabulary Part
851: Electric Welding
IEC 543013:Testing and Inspection of Medium Voltage Electrical
Equipment
Appendix B: Record of AmendmentsIssue 0:New Document based on AA
STD 565005 (April 2011)
Appendix C: Site Test Certificate Motors
Appendix D: Site Test Certificate Motor Control Centres
Appendix E: Site Test Certificate Transformers
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26
Sheet1CERTIFICATE NO.
1Manufacturer
2M.C.C. Description
3Current RatingA
4Fault CurrentkA
5Busbar Voltage
6Megger Test on Busbars
Megger Voltage
Red to Yellow
Red to Blue
Blue to Yellow
Red to Earth
Blue to Earth
Yellow to Earth
7Busbar Connections TightYESNO
8Panels Connections TightYESNO
9Buswire Connections TightYESNO
10Earth Connections TightYESNO
11MCC Earth Bar to Main Earth ConnectionYESNO
12Foundations Bolts CompleteYESNO
SIGNED FOR AND ON BEHALF OF THE CONTRACTOR:DATE:
Sheet1CERTIFICATE NO.
1Plant Item NO.
2Transformer duty
3Make
4kVA
5Primary Volts
6Secondary Volts
7Primary Amps
8Secondary Amps
9Vector Group
10Cooling
11Serial No.
12INSULATION TEST
Primary to EarthYESNOm
Test VoltageV
Secondary EarthYESNOm
Test VoltageV
13Temperature AlarmYESNOC
Temperature TripYESNOC
14Buchholz TestedYESNO
15Neutral CT ConnectedYESNO
16Main Earthing CompleteYESNO
17Silica Gel Breather ServicedYESNO
18Conservator Oil Level OKYESNO
19Tap Changer set on TapYESNO
SIGNED FOR AND ON BEHALF OF THE CONTRACTOR:DATE: