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MINISTRY OF HOUSING Western Sector Projects Sitework &
Infrastructure OMRANIA and ASSOCIATES Project Specification
EARTHING SYSTEM SECTION 26 05 26 - 1
SECTION 26 05 26
EARTHING SYSTEM PART 1: GENERAL
1.01 SECTION INCLUDES
A Earthing system including, but not limited to the
following:
1. Earth rods.
2. Earth conductors.
3. Earth connection bar.
4. Earthing of various systems.
1.02 RELATED SECTIONS
A Section 01 31 00 Project Management and Coordination.
B Section 0133 00 Submittal Procedures.
C Section 01 61 00 Common Product Requirements.
D Section 01 78 36 Warranties.
E Section 26 05 00 Common Work Results for Electrical.
F Section 26 05 53 Electrical Identification.
G Section 26 05 19 LV Cables and Wires.
H Section 33 71 19 Underground Electrical Services.
I Section 26 11 13 Unit Substation.
J Section 26 08 00 Testing and Commissioning of Electrical
Systems.
1.03 REFERENCES
A SASO Saudi Arabian Standards Organization.
B IEC 60364 Electrical Installations of Buildings.
C BS 7430 Code of Practice for Protective Earthing of Electrical
Installations.
D BS 7671 Requirements for Electrical Installations (IEE Wiring
Regulations).
E SEC DPS SEC Distribution Planning Standards.
F SEC SDMS SEC Distribution Materials Specifications.
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MINISTRY OF HOUSING Western Sector Projects Sitework &
Infrastructure OMRANIA and ASSOCIATES Project Specification
EARTHING SYSTEM SECTION 26 05 26 - 2
G SEC SDCS SEC Distribution Construction Standards.
1.04 SUBMITTALS
A Comply with section 0133 00.
B Submit manufacturers data, illustrated leaflets, dimensions,
fixing details and description of the proposed products.
1.05 QUALITY ASSURANCE
A Manufacturers: Firms regularly engaged in the manufacture of
earthing equipment, whose products have been in satisfactory use in
similar service for not less than 5 years. Preference shall be
given to local manufacturers and suppliers/agents.
B Installer: Firms regularly engaged and qualified with at least
5 years of successful installation and experience on projects with
installations similar to that required for this project.
C All equipment furnished under this Specification shall conform
to the requirements of IEC, SASO and BS.
1.06 DELIVERY, STORAGE AND HANDLING
A Comply with 01 61 00.
B All products shall be carefully packed to avoid damage during
transportation.
1.07 WARRANTY
A Comply with section 01 78 36.
1.08 SEC/MUNICIPALITY COMPLIANCE
A Contractor shall comply with all applicable SEC distribution
material specification, construction and planning standards for
power distribution networks and municipality specification for road
lighting. Some of the specifications and standards are attached
with the contract documents for guidance, however contractor shall
obtain copy of all applicable specification and standards from the
concerned authorities as required on site or instructed by the
Engineer.
B Any conflict found between this project specification and SEC
or municipality specification/standards shall be immediately
brought to the notice of Engineer for final decision.
PART 2: PRODUCTS
2.01 ACCEPTABLE MANUFACTURERS
Not Used.
2.02 GENERAL
A All materials required for earthing system shall be furnished
new and undamaged in accordance with the requirements stated in
this section.
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MINISTRY OF HOUSING Western Sector Projects Sitework &
Infrastructure OMRANIA and ASSOCIATES Project Specification
EARTHING SYSTEM SECTION 26 05 26 - 3
B Conduct soil electrical resistivity tests at four locations
(minimum) to be advised by the Engineer. The earthing calculations
based on the test results shall be submitted for Engineers
approval, to demonstrate that the proposed design of the earthing
system complies with the Specification and standards.
C A connection shall be provided from the main earth loop for
medium voltage equipment in the electricity supply authority
incoming equipment room, Earth pits shall be installed in
accordance with the requirements of the electricity supply
authority having jurisdiction, which shall be isolated from the
main earth loop.
D Separate earth pits shall be installed in communications
rooms, in accordance with requirements of the telecommunications
utility supply authority having jurisdiction, which shall be
isolated from the main earth loop.
2.03 EARTH RODS
A Earth rods of the 'copper-weld' (copper-clad rods constructed
with a minimum 0.25 mm thick copper exterior sleeve inseparably and
permanently molten-welded to a central high tensile steel core for
rigidity) type shall be used.
B Earth electrodes for each system shall have an interconnected
resistance to earth of not more than 5 Ohms. Where this value is
exceeded, the system shall be augmented by additional electrodes
connected in parallel spaced at approximately four meters apart
until this value is reached.
C The diameter and length of earth rods shall be as per details
shown on drawings or as approved by the Engineer.
2.04 EARTH CONDUCTORS
A Size of earth conductors shall be as shown on the drawings and
in accordance with applicable standards.
B Earth conductors shall be as follows:
1. Outdoor Underground: Soft drawn bare high conductivity
annealed plain stranded copper conductor.
2. Inside Building: Same as for outdoor conductor but with
green/yellow colored Poly Vinyle Chloride (PVC) insulation.
C PVC insulated copper conductor cable shall be used for final
connections from earth loop to structures, equipment, etc and for
earthing/bonding of equipment and metalwork inside the
building.
D All copper to copper connections, splices, taps, etc. in
conductors and at accessories for termination shall be made by the
exothermic weld process. Joints for underground installation shall
be epoxy resin encapsulated before burial.
E Earth conductor in the conduit shall be continuous through the
conduit run with bushing earth connection and terminated on the
panel board earthing.
2.05 EARTH CONNECTION BAR
A For connection of MV and LV equipment, each sub-station shall
have high conductivity
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MINISTRY OF HOUSING Western Sector Projects Sitework &
Infrastructure OMRANIA and ASSOCIATES Project Specification
EARTHING SYSTEM SECTION 26 05 26 - 4
copper, earth connection bar with minimum dimensions of 50 x 6
mm and mounted on porcelain insulators. The bar shall be of
suitable length with pre-drilled holes at a minimum distance of 50
mm between hole centres.
B Earth connection bars for transformer neutral and LV
switchboard frame shall be separate from earth bar for MV and
transformer frame.
C MV generator frame and neutral shall be connected to the same
earth connection bar.
D Each earth connection bar shall have a permanent label to
identify the connections, together with the wording "Main Earth
Bar".
PART 3: EXECUTION
3.01 INSPECTION
A Comply with section 01 31 00.
B Examine the area and conditions under which the earthing
systems are to be installed and correct any unsatisfactory
conditions detrimental to the timely and proper completion of the
work. Do not proceed with the work until unsatisfactory conditions
have been corrected in a manner acceptable to the Engineer.
3.02 GENERAL INSTALLATION REQUIREMENTS
A The installation shall be carried out in accordance with IEC.
The position of all conductors, joints and terminals shall be
approved by the Engineer prior to commencing the work.
B All electrical equipment shall be connected to the earth with
copper earth conductor. The term "electrical equipment" shall
include all metal enclosures containing electrical connections or
bare conductors. Individual devices such as solenoids, pressure
switches, and limit switches shall be exempt from this requirement
unless the device requires earthing for proper operation. Large
equipment such as power distribution boards or motor control
centers shall be furnished with an earthing bus, which shall be
connected at two points to the earth. All earth connection surfaces
shall be cleaned immediately prior to connection. Provide all
earthing material required but not furnished with the
equipment.
C All exposed non-current carrying metallic parts of all
installations shall be effectively earthed. Steel conduit systems,
metallic equipment enclosures, metallic lighting fixtures, cable
trays, all non-current carrying metal parts of electrical systems
and any other equipment or system components shall be earthed and
the connection shall be extended to the nearest panel board earth
or earthing bar in the sub-station.
D The conductive sheaths and armor of cables shall be connected
to earth.
E All connections and joints for the earthing system including
bonding connections shall be made using the "Exothermic" process to
produce a fused joint.
3.03 EARTH ROD INSTALLATION
A All earth rods shall be installed at suitable locations and to
a depth to achieve the required resistance. Where the earth rod
length exceeds 2.5 m, standard sections shall be connected with
aluminum bronze coupling to extend the rod.
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MINISTRY OF HOUSING Western Sector Projects Sitework &
Infrastructure OMRANIA and ASSOCIATES Project Specification
EARTHING SYSTEM SECTION 26 05 26 - 5
B Earth rods shall be driven with a cap driving stud.
C All connections between rods and earthing conductors shall be
made by removable bolted connections.
D All earth rods shall have inspection pits as shown on the
Drawings. Inspection pits shall be constructed from pre-cast
concrete. All connections to the earth rod shall be exposed when
the cover is raised. Attach a DANGER - ELECTRICITY sign to the wall
of the inspection pit. Use English and Arabic white letters on red
background. Inspection pit cover shall be constructed from cast
iron.
3.04 EARTH CONDUCTOR INSTALLATION
A Provide standard sizes of bare or PVC insulated stranded
copper conductor for earth continuity as required and approved by
the Engineer, whether shown on the drawings or not.
B Suitable earthing facilities acceptable to the Engineer shall
be furnished on electrical equipment to consist of compression type
terminal connectors bolted to the equipment frame or enclosure and
providing a minimum of joint resistance.
C The conduit system shall not be considered as continuous for
earthing purposes. A separate
earth conductor shall be installed in the same conduit with the
phase and neutral conductors. The separate earth conductors shall
be sized according to calculated short circuit current and
applicable standards. No earthing conductors shall be smaller than
2.5 mm2
D Exposed conductors shall be installed inconspicuously in
vertical or horizontal positions on supporting structures. When
located on irregular supporting surfaces or equipment, the
conductors shall run parallel to or normal to the dominant
surface.
unless this is part of a multi-core cable. Where flexible
connections are made to equipment, earthing jumpers shall be
provided. All connections of heavy gauge steel conduit system shall
be checked for good electrical continuity.
E Conductors routed over concrete, steel or equipment surfaces
shall be kept in close contact with those surfaces by using
fasteners located at intervals not exceeding 1 meter.
F Exposed earthing conductors shall be securely fastened to the
mounting surface using copper or brass straps.
G Clamps, connectors, bolts, washers, nuts and other hardware
for bolted connection to earthing system shall be of copper.
H Exothermic welds shall comprise molds, cartridges, materials,
and accessories as recommended by the manufacturer.
I Earthing conductors entering the building shall be installed
in a 25 mm diameter PVC conduit. Waterproofing shall be provided at
all entries of earth conductors, details of which shall be approved
by the structural engineer.
J Earth conductors shall be buried at a minimum depth of 750 mm
below finished grade.
K Underground conductors shall be buried in clean sifted
earth.
L Except for sub-stations and electrical rooms, the exposed
earth conductor shall run in protective pipes for runs below 900 mm
from floor level. Pipes shall also be provided at locations where
conductor is likely to be subject to physical damage.
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MINISTRY OF HOUSING Western Sector Projects Sitework &
Infrastructure OMRANIA and ASSOCIATES Project Specification
EARTHING SYSTEM SECTION 26 05 26 - 6
M Extensions from the earth loop as shown on the Drawings shall
be provided for connection to electrical equipment. Connect the
earthing conductor to equipment, earth bus, pad or lug. In addition
to the earth grid extension conductors, an earth cable to each end
of the earth bus in each assembly of power distribution board or
panel boards shall be provided.
N Where an earth conductor is included with the phase conductors
of power circuits, the earth conductor shall be connected to the
equipment earthing facilities and to the source earth bus. Where an
earth conductor is not included with the phase conductors, the
equipment shall be earthed by connecting a separate earth cable to
the equipment earthing facilities and to the tray earthing cable or
source earth bus.
3.05 EARTH LOOP IMPEDANCE
A The completed earthing system shall have sufficiently low
impedance to limit the voltage to earth and to facilitate the
operation of the current protective devices in the circuit. Earth
loop impedance shall not exceed the values specified in BS or other
applicable standards.
3.06 BUILDING SYSTEMS EARTHING
A Building low current systems including communication, control
and alarm functions shall be provided with earthing as shown on the
drawings and in the relevant specification section. Where
applicable, requirements of functional earthing shall also be
complied with.
B The installation of earthing for building systems shall be in
accordance with the recommendations of standards, and the
applicable provisions of this section.
3.07 SUPPLEMENTARY AND EQUI-POTENTIAL BONDING
A In accordance with Section 547 of the IEE Wiring Regulations
(BS 7671), bonding conductors shall be installed in appropriate
locations to ensure all simultaneously accessible exposed or
extraneous conductive parts are at equal potential. Undertake such
tests and install such supplementary bonding conductors that are
necessary to ensure compliance with these requirements.
B Supplementary bonding conductors shall conform to the
requirements of section 547-03 of the IEE Wiring Regulations and
shall have a minimum cross-sectional area of 2.5 mm2 where
mechanically protected and 4.0 mm2
C Main equi-potential bonding conductors shall conform to the
requirements of section 547-2 of the IEE Wiring Regulations and
shall have a minimum cross-sectional area of 6.0 mm
where not so protected.
2
3.08 FIELD QUALITY CONTROL
.
A Comply with section 26 08 00.
B Earth resistance tests shall be carried out after installation
of the individual earthing systems in accordance with the
specification. Earth resistance tests shall be carried out in
accordance with section 713-11 of the IEE wiring regulations 16th
edition and the readings obtained shall be officially recorded by
all witnessing parties.
C Prior to connection of earth rods to the earthing system, the
earth resistance of individual earth rods shall be measured by
using an approved type of earth resistance tester.
D After completion of all connections of the earthing system,
the earth resistance shall be measured from the earthing test point
in the presence of the Engineer.
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MINISTRY OF HOUSING Western Sector Projects Sitework &
Infrastructure OMRANIA and ASSOCIATES Project Specification
EARTHING SYSTEM SECTION 26 05 26 - 7
E In addition to above, carry out any test(s) required to comply
with the procedures of the electricity supply authority (SEC) for
power connection requirements.
F All earth resistance test reports shall be submitted for the
Engineers approval.
END OF SECTION
SECTION 26 05 26PART 1: GENERALSECTION INCLUDESContractor shall
comply with all applicable SEC distribution material specification,
construction and planning standards for power distribution networks
and municipality specification for road lighting. Some of the
specifications and standards are att...Any conflict found between
this project specification and SEC or municipality
specification/standards shall be immediately brought to the notice
of Engineer for final decision.
PART 2: PRODUCTSGENERALAll materials required for earthing
system shall be furnished new and undamaged in accordance with the
requirements stated in this section.
EARTH RODsEarth rods of the 'copper-weld' (copper-clad rods
constructed with a minimum 0.25 mm thick copper exterior sleeve
inseparably and permanently molten-welded to a central high tensile
steel core for rigidity) type shall be used.Earth electrodes for
each system shall have an interconnected resistance to earth of not
more than 5 Ohms. Where this value is exceeded, the system shall be
augmented by additional electrodes connected in parallel spaced at
approximately four meters a...
Earth conductorsSize of earth conductors shall be as shown on
the drawings and in accordance with applicable standards.Earth
conductors shall be as follows:PVC insulated copper conductor cable
shall be used for final connections from earth loop to structures,
equipment, etc and for earthing/bonding of equipment and metalwork
inside the building.All copper to copper connections, splices,
taps, etc. in conductors and at accessories for termination shall
be made by the exothermic weld process. Joints for underground
installation shall be epoxy resin encapsulated before burial.Earth
conductor in the conduit shall be continuous through the conduit
run with bushing earth connection and terminated on the panel board
earthing.
earth connection bar
PART 3: EXECUTIONINSPECTIONExamine the area and conditions under
which the earthing systems are to be installed and correct any
unsatisfactory conditions detrimental to the timely and proper
completion of the work. Do not proceed with the work until
unsatisfactory conditions ha...
general installation requirementsAll electrical equipment shall
be connected to the earth with copper earth conductor. The term
"electrical equipment" shall include all metal enclosures
containing electrical connections or bare conductors. Individual
devices such as solenoids, pressu...All exposed non-current
carrying metallic parts of all installations shall be effectively
earthed. Steel conduit systems, metallic equipment enclosures,
metallic lighting fixtures, cable trays, all non-current carrying
metal parts of electrical system...The conductive sheaths and armor
of cables shall be connected to earth.All connections and joints
for the earthing system including bonding connections shall be made
using the "Exothermic" process to produce a fused joint.
earth rod INSTALLATIONAll earth rods shall be installed at
suitable locations and to a depth to achieve the required
resistance. Where the earth rod length exceeds 2.5 m, standard
sections shall be connected with aluminum bronze coupling to extend
the rod.Earth rods shall be driven with a cap driving stud.All
connections between rods and earthing conductors shall be made by
removable bolted connections.All earth rods shall have inspection
pits as shown on the Drawings. Inspection pits shall be constructed
from pre-cast concrete. All connections to the earth rod shall be
exposed when the cover is raised. Attach a DANGER - ELECTRICITY
sign to the wa...
EARTH CONDUCTOR INSTALLATIONProvide standard sizes of bare or
PVC insulated stranded copper conductor for earth continuity as
required and approved by the Engineer, whether shown on the
drawings or not.Suitable earthing facilities acceptable to the
Engineer shall be furnished on electrical equipment to consist of
compression type terminal connectors bolted to the equipment frame
or enclosure and providing a minimum of joint resistance.The
conduit system shall not be considered as continuous for earthing
purposes. A separate earth conductor shall be installed in the same
conduit with the phase and neutral conductors. The separate earth
conductors shall be sized according to calculat...Exposed
conductors shall be installed inconspicuously in vertical or
horizontal positions on supporting structures. When located on
irregular supporting surfaces or equipment, the conductors shall
run parallel to or normal to the dominant surface.Conductors routed
over concrete, steel or equipment surfaces shall be kept in close
contact with those surfaces by using fasteners located at intervals
not exceeding 1 meter.Exposed earthing conductors shall be securely
fastened to the mounting surface using copper or brass
straps.Clamps, connectors, bolts, washers, nuts and other hardware
for bolted connection to earthing system shall be of
copper.Exothermic welds shall comprise molds, cartridges,
materials, and accessories as recommended by the
manufacturer.Earthing conductors entering the building shall be
installed in a 25 mm diameter PVC conduit. Waterproofing shall be
provided at all entries of earth conductors, details of which shall
be approved by the structural engineer.Earth conductors shall be
buried at a minimum depth of 750 mm below finished
grade.Underground conductors shall be buried in clean sifted
earth.Except for sub-stations and electrical rooms, the exposed
earth conductor shall run in protective pipes for runs below 900 mm
from floor level. Pipes shall also be provided at locations where
conductor is likely to be subject to physical damage.Extensions
from the earth loop as shown on the Drawings shall be provided for
connection to electrical equipment. Connect the earthing conductor
to equipment, earth bus, pad or lug. In addition to the earth grid
extension conductors, an earth cable to...Where an earth conductor
is included with the phase conductors of power circuits, the earth
conductor shall be connected to the equipment earthing facilities
and to the source earth bus. Where an earth conductor is not
included with the phase conducto...
EARTH LOOP IMPEDANCEThe completed earthing system shall have
sufficiently low impedance to limit the voltage to earth and to
facilitate the operation of the current protective devices in the
circuit. Earth loop impedance shall not exceed the values specified
in BS or oth...Prior to connection of earth rods to the earthing
system, the earth resistance of individual earth rods shall be
measured by using an approved type of earth resistance tester.After
completion of all connections of the earthing system, the earth
resistance shall be measured from the earthing test point in the
presence of the Engineer.