11.method Statement Electrical Work
11.method Statement Electrical Work
11.method Statement Electrical Work
2. Location of Activity
Inside/outside of the building.
3. Scope of Work.
The method statement covers all activities related to the Electrical works.
General Description
The purpose of this Method Statement is to give a general outline of the methodology that will be used
for electrical works at, The WTC to identify the risk associated during the electrical works and to
identify the quality control system to ensure full compliance with the client’s requirements and as per
the project specification.
Activities
Fixing under floor sleeves.
4.Responsibilities
Al Qooz Contracting Project Manager shall be responsible for the implementation of this
method statement.
Al Qooz Contracting Project Manager / Project Engineer will ensure that the Resources
are available to carry out the works as scheduled.
The Project Engineer / Site Engineer are responsible to carry out the works as per
approved Shop Drawings, Method statements.
The Site Engineer / Supervisor are responsible to ensure that the work has been carried
out as per drawings and inspections are done as per contract.
5.Resource Requirement
General
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Materials
Drawings.
Sleeves.
In the beginning of each project and before casting the retaining wall, we
have to Make sure that we already fixed our sleeves for DEWA high voltage
cables, Etisalat Cables or for earthling system, officers the size, No and
heights of the sleeves as Per their requirements
Conduits in the Slabs.
In this stage we have to start our works directly after fixing the shatter,
since there are a lot of works to be done before fixing the steel, like marking
the location for all the lighting, power, and fire alarm points, then fixing the
loop in boxes, making the required holes for the dropped conduits for
switches, bells, break-glasses and DB’s. After finishing the steel work
completely, we will start fixing our conduits as per the approved shop
drawings, off course, we have to avoid passing the conduits in the wet
areas, we have to minimize the bends for the conduits, and to be fixed
properly with the steel, in addition to using expansion couplers where are
coming expansion joins. At the end we will us masking tap to close all the
end opening of the conduits.
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Before casting any column in the site, we have to check if there is any
Switch Socket, bell or break glass fixed on the column. If there is any, we
have to fix the GI or PVC box in the proper way so that it will be touch with
shatter of the. Column from inside and the conduit will be extended to the
top of the column.
Before casting any column in the site, we have to check if there is any
Switch Socket, bell or break glass fixed on the column. If there is any, we
have to fix the GI or PVC box in the proper way so that it will be touch with
shatter of the Column from inside and the conduit will be extended to the
top of the column.
After finishing the block work in each floor, we will start marking the
location of all the switches, sockets, telephone outlets, TV outlets, break
glass and bells as per the approved shop drawings. Then we will start
chasing and chipping the marked locations by using the grinder, accordingly
we will fix the GI boxes with minimum 5 mm away from the wall to make
sure that the box is flush with the plaster. Next day we will terminate the
conduits with the GI boxes.
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Usually, we always inform the main contractor, before starting the block
work to use a blocks of 200 mm. width instead of 100 mm. and to locate
plaster level points only in the location where is coming recessed DB’s, so
that we can fix the enclosures properly and to ensure the enclosures are
completely flush with plaster. The mounted height of the enclosures will be
1300 (bottom of panel).
Distribution board will be aligned, leveled and securely fastened to the wall.
The surface mounted panel boards will be fixed at least 25 mm from wall:
ensuring supporting members do not prevent flow of air.
Distribution board interiors will not be installed in cabinets until all conduits
connections to the cabinet have been completed.
Trim for flush mounted cabinets will be installed in plaster frame, flushed
with furnished wall. Trim will be installed plumb and square to finish
painting.
Before starting the wiring for the above mentioned activities, we have to
make sure that the plasterwork is finished completely in that area / floor &
there is no more water still on the walls.
Before start pulling the wires we will be sure that there is no water or any
rubbish inside the conduits.
At the false ceiling area (60 x 60), we have to use a ceiling rose with a heat
resistance wire & where are coming a gypsum board ceiling, we have to
extend the wires from the slab to the expected level of the gypsum ceiling
through a flexible conduits.
For the light & Power circuits, wires & cables will be used as per the
approved material submittal (2.5mm2 for the lighting circuits & 4.0mm2 for
the power circuits).Lighting & Power circuits will be run in separate
conduits.
The wires & cables will be installed in conduits, trunking and ladders as per
the approved shop drawings.
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For branch circuit work, originating from light & power panel boards will be
arranged as per the approved drawings. Loads on various phases of panel
boards will be balanced as per he approved load schedules.
For pulling the wires, we will install 3mm galvanized standard steel wire
with wooden blocks fastened at ends in empty service conduits.
At every branch circuit outlet & pull-box, every cable passing through will
be left slack to allow inspection & for connection to be made. Cables
terminating in outlet boxes will be left with at least 250mm extra length for
terminations.
All circuits will be properly labeled during the pulling work to facilitate the
terminations at the respective devices.
After the pulling circuit works completely, all the circuits will be checked &
tested if any open circuits, short circuits, earthing continuity & excessive
resistance or leakage.
Cable Trays & Ladders will be “as specified” type as per the approved
material submittal.
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Earthing jumpers will be installed on trays & ladders between the lengths
and where required to ensure effective electrical continuity irrespective of
whether a separate protective earth conductor is required or not.
After we finished from fixing the cable tray, C-channels in the proper way,
we will start pulling the armored cables from the main electrical room to
the all electrical rooms one by one and with more care to avoid any damage
for the cables, after that it will be tied strongly with the vertical C-channels
using cable cleats then it will be terminated to the MDB’s, SMDB’s through
cable glands.
Use and install cables only as shown on consultants approved shop
drawings & as directed by the manufacturer
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Lay cables in one length unless otherwise indicated. Obtain permission from
Engineer for all through joints, and where overall length requirement
exceeds practical drum size.
Use drum stands, drum axles, fair leads, rollers, cable stockings and other
equipment as recommended by the cable manufacturer and as appropriate
to the method of installation.
Install cables so that they are orderly and capable of being withdrawn.
Trunking: In vertical trunking provide pin racks at 3m intervals. Use ties at 2m intervals
for all wires of the same circuit reference. Mark ties with circuit reference
number at 10m intervals.
Conduit: Provide cable clamps in conduit boxes at 10m intervals in vertical conduit.
Place cables side by side or as indicated. Fix using cable ties so that any
cable may be individually removed.
Ensure all joints and terminations and glanding are made by appropriately
qualified Person, using, components and workmanship recommended by
the cable manufacturer& as per local authorities & DEWA recommendation.
Cut all cable ends immediately prior to jointing or terminating. Seal cables
left unconnected for more than 24 hours to prevent the ingress of moisture.
Strip cables to bring out the cores and expose conductors, for the minimum
length required for connection, to leave no exposed length of conductor
after termination. Ensure that strands are not damaged when stripping
cable cores. Twist strands together. Do not reduce number of strands.
Secure all strands at terminations.
Clean arm our thoroughly prior to jointing or terminating. At connections to
equipment and switchgear without integral cable clamping terminals, use
compression type lugs for bolted terminal connections.
Do not bunch more than three cores at clamping terminals or bolted
connections.
Mark cable conductor phasing, or other core identification, at each end of
all cables.
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The Contractor shall be responsible for testing all cables before finally
making off ends and connecting up.
Where cable sheaths are used as earth continuity conductors, glands shall
have the necessary contact surfaces or straps to provide a low resistance
path under fault conditions.
All cable connections to plant shall be made with approved cable lugs,
compression type together with the usage of proprietary tools.
All glands in outdoor situations and wherever else specified, shall be of
weatherproof and water tight type. Gland manufacturers shall be subject to
approval. Glands shall be selected to suit location and type of cable used.
Earthling tags shall be fitted to each gland, on assembly, prior to the lugs
being attached. Ensure to order cable glands in kit form complete with
earth tag, shroud, locknut, neoprene seal etc.
General: All materials and equipments will be furnished and install as per the approved
shop drawings, material submittal and proposed method statement.
The Panel boards will be in accordance with Local Dewa rules &
Requirement. “Standard for Panel Boards” and standard for cabinets and
boxes. Manufactures 380 / 220V, 3-phase, 4 wires, 50Hz.
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Install the connecting conduits to the panel board, ensuring these conduits
will not be used to support the distribution board and all the unused
opening will be properly closed.
The panel Boards will be equipped with circuit breakers with frame size and
trip setting as shown in the approved document.
Before pulling wires inside the Panel Board conduits, conduits will be
checked to be free of burrs, dry and clean.
Wiring will be neatly arranged, accessible and strapped to prevent tension
on circuit breaker terminals.
The arrangement will permit cables to enter bottom and top of the
enclosures and connect to their respective terminals without interference.
Insulation to be removed from the end of each wire and cable with a
pocketknife, being careful not to nick the wire conductor.
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Incoming and outgoing feeder panel will be labeled, engraved and a nearly
typed schedule inside the boards, will describe all the outgoing final sub-
circuits, their rating, the areas and points served.
Light and power circuits will be arranged in the Panel Boards as per the
approved Load Distribution Schedule.
Tags of feeder cables to identify cable or circuit number and conductor size
in accordance with the schedules.
D – Dressing of DBs:
A professional electrician will be carrying out for this work.
Cable terminals will be suitable for the specified cable sizes. Adequate
space will be provided for cable terminations.
Dressing of standard cables will be done by using ferrules of sizes suitable
for accommodating all stands of the cables.
After finishing the 1st coat near the final DB’s, we will start fixing the inside
components and numbering, terminating the wires as per the Load
Distribution Schedules, in addition to fixing a suitable identification labels
to clearly indicate the location and the purpose of each item or circuit.
The glands for various single core and multi core cables will be on the
purposed made and suitable for rigid mounting to the enclosure.
Finally, after the dressing completed, the door will be fixed and covered for
protect the panels from any damaged, ensuring that all the engraved labels
fixed for the DB sections, main isolator, ELCBs etc.,
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We will start fixing the SMDBs after painting at least 1st coat in the Electrical
rooms completed. The fixing height for the SMDB’s will be at 800 mm. from
finished floor level as per DEWA regulations as well as trunking
arrangement for the meters or (at height not exceeding 2 meters to the top
of the Panel Boards from the finished floor level)
SMDBs will be wall or floor mounted type depending of the frame size of
the board. All the trunking arrangements will be done as per the approved
shop drawings.
In case of floor mounted boards (MCC-R) a depressed floors will be
provided with galvanized steel support structures to raise the level of the
panel.
Wiring, cabling and dressing for the SMDBs will be nearly similar to dressing of
the DBs and all the connections will have front access only
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All the meters (CT’s meter and check meters) will be installed in the
respective main distribution boards after tested and calibrated by DEWA.
Testing:
On completion of the installation and prior to its being made “Alive” for
service, all the electrical test will carried out all sections of the works in the
presence of the Consultants’ and all the tests will be carried out in
compliance with the DEWA regulations and the contract specifications. All
the test reports will be submitted to the Consultants’ along with the As-built
drawings and Operation and Maintenance documents.
After finishing the pre-final coat for the building, we will start fixing the
wiring Accessories, light fittings, fire alarm devices. Of course the fitting
where is coming in the false ceiling should be fixed in the proper way with
more supports if required:
Cover plate finish, all accessories to match - Molded plastic, color - white.
Neon indicator with red lens, illuminated in `ON’ position, for connection
units.
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Installation General.
All accessories shall be properly aligned with vertical edges; plumb and
horizontal edges level and mounted at the height recommended below and
shall be to the approval of the Engineer.
All flush accessories shall have cover plates fitted correctly onto the wall or
ceiling or any other services. Any accessories found to be incorrectly aligned
after installation will have to be removed and re fixed.
Local lighting switches for the control of lighting circuits shall be of the
following types:
For single and multi-gang units in all areas throughout the building where
installation work is concealed, switches shall be of the 10A grid switch type
flush pattern and shall be mounted in suitable metal boxes..
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For areas where switches are shown connected to different phases, in the
same location, multi-gang switches are to be used with an approved phase
barrier and shall also be to the requirement of the local authority..
ii) Obtain Etisalat / DIC (Dubai Internet City) approval for telephone workshop
drawing.
iii) Install sleeves for main telephone incomer. Install telephone boxes &
telephone junctions boxes. Prior co-ordination with Etisalat is required
for exact location of telephone main cable entry sleeve.
vii) Run telephone / data cables from intermediate distribution frame panel
into main distribution frames in ground floors low current room via
trunking / cable riser.
viii) Install distribution frame panels, telephone / data outlets and terminate
relevant wires and cables.
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Obtain Civil Defense Department approval on the fire alarm system after
consultant’s approval.
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Install trunking / cable trays in risers as highlighted in relevant shop drawings.
Install and terminate low current systems devices in various areas.
Install wires from various devices into trunking, run down to respective
activity to main panel.
Install main panels and terminate wires.
The Following are the tests that will be carried out on final electrical circuits
and distribution boards. The observations and readings will be recorded in
the appropriate formats.
a) Visual Check
Check that all the metallic components are properly earthed / binded.
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b) Polarity Check
Ensure that single pole switches are installed in the live conductor.
Where Screw type lamp holders are in circuit, ensure that the outer or
screwed conductor is connected to the neutral conductor.
The continuity resistance between the open ends of each of the three rings
of circuit (i.e. phase, neutral and earth) is to be measured for all ring final
circuit conductors with D.C. ohm meter and the value to be verified with the
permissible limits.
The following are the tests that will be carried out on distribution cables.
The observation / readings of the tests will be recorded in the appropriate
formats.
a) Visual Check
The installation of the cable to be checked to ensure the correct laying,
proper glanding, corrects termination, adequate supports, labeling,
identification etc.
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e) Insulation Resistance
Note:- The mains supply can be switched on to the final circuit to enable further
tests to be carried out, which require supply voltage.
Earth fault loop impedance is to be checked for each final circuit with an
impedance tester. (RCCB to be by passed during test) and the reading is to
be verified with the permissible limit.
g) RCCB Test.
All RCCB (ELCB) are to be checked by means of a RCCB tester with minimum
3 different set currents (One setting above, one below and one rated
sensitivity currents of an ELCB) and the trip times are to be recorded. The
values to be verified with the permissible limits.
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h) Circuit Performance
After all the above tests are conducted and observed that they are
satisfactory, and operational test to verify the desired performance of the
circuits need to be carried out. They are as follows:
In case of lighting circuits, operate all the switches connected in the circuit
one ensures their functioning to the desired light fixture in the desired
manner.
In case of ring / radial circuits, test all the sockets with a test lamp to ensure
the availability of power.
In case of any other fixed equipment, operate the relevant switch and
observed the functioning of the equipment.
- Measure and record the current in all phase of the incoming cables in lighting DB’s
keeping all the lights “ON”.
The following are the tests that will be carried out on the MDB’s / SMDB’s /
MCC’s.
All the bolts / nuts and bus bar connections are to be checked to ensure
that all are properly tightened.
All the meters and selector switches are to be checked to ensure that
correct selection and ratings.
c) Interlock Tests.
d) Functional Test.
To start the functional tests, check the control circuit of each starter /
system for its correct operation in regard to switching on actuation of
thermal overload and emergency stop – lock etc.
The operation of starter for various equipment such as pumps, fans etc. is
to be checked to ensure the desired function and currents at various stages
of loads are to be recorded.
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All the earth leakage circuit breakers are to be checked by means of RCCB
tester, setting 50%, 100% and 150% of the rates sensitivity currents and the
respective trip times to be recorded. The readings are to be recorded. The
readings are to be compared with the characteristic values of the ELCB’s to
ensure their correct operation.
Where core balance CT’s and EL, relays are provided for earth leakage
protection, an earth leakage current of known valve is simulated by external
means and the trip times is to be recorded for 50 %, 100% and 150% of the
rated sensitivity currents. The readings are to be compared with the
characteristic values of the EL relay (RCCB tester can be used for simulation
of earth leakage currents).
a) Visual Check
All the earth electrode in the earth pits is to be visually inspected proper
installation and connections.
All the protective conductors from the earth electrode to the main boards
and distributions are to be visually inspected for proper installation and
connections.
c) Continuity Test.
The following are the tests that will be carried out on the lighting protection
system.
a) Visual Check.
All the joints are to be cleaned & lightened to maintain good continuity
resistance.
c) Continuity Test.
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The following are the tests that will be carried out on the Fire Alarm System.
All the cables connected to the fire Alarm system control panel and battery
is to be inspected and checked for proper connections as recommended by
the manufacturer.
The whole of the installation in general is to be checked to ensure proper
installation.
b) Functional Test.
After restoring the power supply to the panel, the necessary adjustments
and settings are to be made so that the panel is put into operation.
Once the panel is in operation, all the detectors / break glasses are
simulated to be activated by giving smoke and the display of zone nos. of
the detector activated is
witnessed on the panel and the operation of he LED on the detector is to
be noted. Further, the indication on the repeated control panel is to be
checked and verified for correct functioning.
During the above testing the sounder circuits and bells should be checked
and ensured that they function correctly.
Faults such as power supply failures, battery, and open circuit of zones are
simulated and the respective visual indications on the panel by means of
LED are to be checked and ensured for proper functioning.
The following are the tests that will be carried out on the Fire Alarm Cables.
The observations / readings of the tests will be recorded in the appropriate
format.
a) Visual Check.
The installation of the cable to be checked to ensure the correct laying
proper termination, adequate clipping, labeling identification etc.
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7.TEST REPORTS
8.Manpower.
9.Records.
No. Document
1. Inspection Request
2. Area clearance form
10,Approvals
Project Manager
Engineer
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