EHV Handbook ENG LowRes
EHV Handbook ENG LowRes
EHV Handbook ENG LowRes
Issued by
Transmission Maintenance department
Transmission Power division
Dubai Electricity and Water Authority
HAND BOOK
on EHV overhead lines
and underground cables
TABLE OF CONTENTS
About this book .............................................................................................................................................................. 6
Chapter 4 - PROTECTIVE REGULATIONS & PRECAUTIONARY MEASURES FOR THE PROTECTION OF TRANSMISSION LINES
5.1 Patrolling........................................................................................................................................... 78
5.2 Pre-Commission Inspection................................................................................................................ 78
5.3 Contractors Work Supervision............................................................................................................ 78
5.4 Site Instruction Notice........................................................................................................................ 79
5.5 Notice to Stop Work.............................................................................................................................81
5.6 Awareness Tool Box talk...................................................................................................................... 82
List of Abbreviations.................................................................................................................................... 90
Contact Us...................................................................................................................................................91
This book is a guide to the protection regulations for extra-high-voltage (EHV) overhead lines and underground
cables for contractors, consultants, strategic partners, as well as anyone who is working on or near DEWAs
electricity transmission network. It provides the necessary information to ensure that their projects conform
to these regulations and what information, documents and other criteria must be provided to ensure their
successful completion.
To avoid accidents and potential blackouts, and minimise risk. You can know what to do and what is required to
ensure your work can be carried out in complete safety.
24/48
18mm
132kV Power & Fiber Optic cable in 50cm Wide Trough in Congested Area Due to Inadequate Space
(132kV Power / F.O Cable Laid through duct (with 11 Ducts) (Open Cut Method for unmade area)
Cable Laying Method Directly Buried 132kV Power / Pilot / F.O. Cable
1.4.4 Vertical mounted link box with steel bollard 1.4.5 Vertical mounted link box with steel crash
Protection barrier protection in road side
1.4.6 Surface / pole type route marker installed in 1.4.7 Flush type route marker at paved areas
every 50 m interval
1.4.9 Installation of Permanent Height limit gantry at road crossing tower location
1.4.11 Installation of signboards indicating prohibition of any type of activity under/within overhead line corridor
Hazard
Sl.No. Hazards
level
a Works within and around Transmission lines without prior notification or High
obtaining NOC, violation of NOC condition and Method statement
Hazard
Sl.No. Precautionary measures
level
a Contractor works within and around the Transmission lines to be allowed Low
with prior notification, valid NOC and following all NOC conditions or method
statement
c OHL clearance confirmed and height-limited gantry provided to work under OHL Low
d Ensure manual excavations are over or in the close vicinity of the Transmission Low
lines
TP/TMD/TLM/LP&N/QP-01.A04a
TRANSMISSION LINE (400/132 KV OHL & CABLE)
WORK NOTIFICATION/ SUPERVISION REQUEST
Notification prior to start works Trial Pit Verification Request Request for standby supervisor for protection
1. Trial Pit
Request to check GPS coordinates before 1. Cable 2. OHL 3. Cable/ OHL
2. Construction NDRC, Piling, Shoring & Anchoring works
Note: This request has to be forwarded to DEWA 2 working days in advance by fax: 04-3229095 or by email to tlm.supervision@dewa.gov.ae,
before start of proposed work.
Request Ref./Date:
Project No. & Title /Name
c) Nearest Landmark
Requested Period: From: To: Timing(Hrs.)
(Work shall be done during DEWA
office Hrs. only) From: To:
Requested Period beyond DEWA From: To: Timing(Hrs.)
office Hrs.: (Justification
letter to be attached)
Note: This request depends on
DEWA approval. From: To:
Site In charge Details Name of the Engineer
Contact No.
Name of the Site
Foreman/Supervisor
Contact No.
Undertaking by working party - We assure you that no any works will be executed by us without prior
intimation to TLM and before DEWA supervisor visits the site/ checks the NOC & provides official clearance
for the above work, which is in the vicinity of 400/132kV Cables / OHL.
Thanking you for your kind cooperation and assuring you of our best services at all times.
TRANSMISSION LINES MAINTENANCE - PATROLLING & NOC TP/TMD/TLM/LP & N/QP - 02.A09.I
4. The proposed work in parallel to the existing 132Kv Direct buried cables and clearance from the proposed work
/excavation edgeisless than2.0m, Trial pit verificationis requiredat minimum10.0m andMaximum 20m.gap. Ifthe
direct buried cables more than 2.0 m away and cable within the Trough, Trial pit verification required atmaximum
50.0m gap. (If the proposed working area length is less than the above mentioned length, Minimum 2 trial pit
verification
required).
5. Location
of
Trial
Pit
should
be
as
shown
only
by
TLP
Supervisor
at
site.
6. Any
discrepancy
of
drawing
to
site
topography
and
other
structures
should
be
corrected
on
the
drawing.
d. Take GPS coordinates of all excavated trial pits that fails to expose the expected cables and write theaccurate
coordinates
on
the
verified
drawing.
C. AFTER
TRIAL
PIT
IS
COMPLETED
AND
READY
FOR
VERIFICATION
1. Clearance (Horizontal, Vertical, Diagonal) from existing cable/trough and nearby cable joint and nearby cable route
angletoproposedworkincluding proposeddrilling pathand entry/exitpit, otherutilities, andstructures (bridge, edge
of
road,
etc.)
should
be
writen
on
Verified
Drawing.
2. GPS
Coordinates
of
proposed
drilling
path
/
entry
and
exit
pits,
piling/Boring/Anchoring
on
drawing
should
be
determined
at
site
by
GPS
Station
at
presence
of
TLP
Supervisor.
3. Circuit name,type ofcable, numberof cables,laying method,number ofspare duct(If any), and typeof area(under
roadway,
condition
of
soil,
crossing
other
structures,
etc.)
where
it
is
installed
should
be
written
on
drawing.
4. Iftheexistingcable/trough, ohl or other transmissionOHL/Cables areconsiderably far or not likely be affected byany
activities of the proposed works, the distance from existing OHL/Cable to work area and the name of nearest
OHL/Cables
should
be
written
on
verified
drawing.
5. Confirm
temporary
roadway
agreeable
with
contractor
and
sketch
on
the
drawing.
(Choose
roadway
that
can
avoid
vehicular
&
machinery
movement
over
transmission
corridor)
6. Any recommendation or other information that should be considered in processing NOCshould be clearly writtenin
drawing
(Soil
condition,
gas/fuel
line,
&
other
precautionary
measures).
DEWA
Staff
comments
Fig 3.1.2 Locating 132kV cable through Trial Pit. Fig 3.1.3 Manual excavation for Trial Pit.
Locating the service by referring the NOC Manual excavation for trial pit to trace the service
Special Cases:
1.
If the 132kV cable cannot be found (HDD area),
DEWAs supervisor will write in the verification, that
the cable has not been found at the expected depth.
A. Road work
a. Proposed scope of work drawing in scale (1:1000) ramp, side wall of ramp, bridge pillar, pier, or
with DLTM coordinates incorporating: underpass to the transmission lines, crossing
i. Existing 400/132kV OHL or cable routes and their protection details
ii. circuit names b. Right-Of-Way cross-section details.
iii. cable joints c.
Details of OHL tower protection (crash barrier),
iv. link box locations including Height limit gantry, fencing details, and
v. clearance from the proposed road edge to the access from the proposed road to the OHL corridor,
cable or trough edge if the proposed road is close to, or crosses the
vi. OHL Horizontal and vertical clearance from the OHL corridor.
proposed road d.
If the proposed road will go over the existing
vii. Horizontal clearance from the tower foundation 132kV cable trough, then the length of the cable
to the road edge protection, spare duct details with end-coordinates
viii. Clearance details from any proposed bridge, must be shown on the drawings.
e. If the proposed road, or road-widening, goes over the n. If there is any other information that you think
existing duct bank, then the edge of the proposed we need to know, please include it.
road needs to be clearly marked in conjunction to the
existing cable duct bank edge. B. Installation of Electrical cables and troughs
f. If the duct bank is being extended, then details and a. Proposed scope of work drawing should be
end-coordinates must be provided for this. submitted to scale (1:1000) with DLTM coordinates
g. If the Proposed road edge is close to the cable joint incorporating the Existing 400/132kV OHL / cable
or link box locations, 4 corners coordinates of the route, circuit names, and cable joints, and link
joint box, then the drawing should include the box locations.
horizontal clearance from the joint or link box to b. Clearance from the proposed scope of work should
the road edge. show the excavation edge to the 400/132kV cables
h. If any utility services or diversions included in the and trough edges and the horizontal and vertical
proposed road work contract, then applicants clearance from the OHL to the proposed scope of
should include the clearance details for these work, and the horizontal clearance from the tower
services, which can include water, drainage, storm foundation to the excavation edge.
water, irrigation pipelines etc., Etisalat duct, high- c. ROW cross section details.
voltage or low-voltage electricity, crossing details, d. Method statement, crossing details, and cable
and protection details. trough protection details.
i. Applicants should show details of any landscaping e. If the works are near to the OHL, then applicants
work included in the road project if they are should provide the clearance details of equipment,
within the vicinity of the existing 400/132kV OHL machinery along with the method statements.
or cable services. f. If the works are close to the OHL, then applicants
j. Applicants should provide clearance from the road should provide details of tower protection
signal post, street-light poles to existing 400/132kV (concrete or steel crash barriers), temporary height
OHL and cables. limit gantries, and safety arrangements.
k. If the 132kV Cable diversions or OHL risings are g. Underground structural works details like cable
included in the road contract, then details of this joints and duct bank.
must be included in the drawing. h. Clearance from the existing joint location to the
l.
Access to the substation must be shown on the proposed joint location for LILO or existing cable
drawing if the proposed road is close to the substation. diversion works.
m. Please ensure that TLP staff have verified and i. Provide evidence and details that TLP staff have
provided the cable and OHL clearance details. verified any cable and OHL clearance.
C. Installation of Pipelines. a. Proposed plot details and plans for work and any
a. Proposed scope of work drawing should show effects.
details such as main pipe, PVC duct for control b. Scope of work details setting out plan including
cables, RTU, valve chamber Etc. in scale (1:1000) access details. If the access to the plot or building
with DLTM coordinates incorporating the existing is over the existing cable routes, this must be
drawing route, circuit names, cable joint and link protected by an additional protection slab and
box locations. spare ducts, with detailed drawings for this.
b. Clearance from the proposed scope of work and c. Please include the clearance from the plot limit,
excavation edge to the 400/132kV cable and trough depth of excavation, and any shoring, anchoring
edge, and the horizontal and vertical clearance and fencing details along with existing 400/132kV
from the OHL to the proposed scope of work, OHL or cable clearances.
horizontal clearance from the tower foundation to d. Fencing details (only see through if cable enclosed).
the excavation edge. e. Undertaking that no materials, cabins, construction
c. ROW cross section details. or materials will be put on on cable reservations.
d. Method statement, crossing details, cable and f. Undertaking for interlock tiles, gardening,
trough protection details. pavement, asphalt etc. that the owner will allow
e. Clearance details of equipment and machinery DEWA unrestricted access and reinstatement will
should be submitted along with method statement, be done by them.
if the works are near or are close to the OHL. g. TLP staff have verified all cable or OHL clearance
f. Details of tower protection (crash barrier) details.
temporary height limit gantry, etc. safety h. If there is any other information that you think we
arrangement to be provided if the works are close need to know, please include it.
to the OHL.
g. Underground structural works details like manholes, E. NDRC, thrust boring, micro-tunnelling and
pumping stations and chambers etc should be
pipe-jacking
submitted along with method statements.
h. TLP staff verified Cable / OHL clearance details. a. The proposed scope of work drawings should be in
i. If there is any other information that you think we plan view and submitted in scale (1:1000) with DLTM
need to know, please include it. coordinates of entry and exit pits incorporating
all existing 400/132kV cables, OHL routes, circuit the excavation edge.
names, cable joints, and link box location (if any). c. ROW cross section details.
b. Longitudinal section of proposed scope of work d. Method statement, crossing details, cable or trough
location indicating the existing 400/132kV protection details.
cables, clearance from the bottom of the trough e. Clearance details of equipment / machinery to be
and the clearance from entry and exit pit to the submitted along with method statement, if the
existing cables. works are near the OHL.
c. Horizontal and vertical clearance from the OHL to f. Details of tower protection (crash barrier) and
the proposed scope of work, Horizontal clearance temporary height limit gantries, etc. with safety
from the tower foundation to the excavation edge arrangement to be provided if the works are close to
d. Clearance details of equipment / machinery to be the OHL.
submitted along with method statement, if the g. Clearance details of chamber and installation details.
works are near the OHL. h. TLP staff verified Cable / OHL clearance details.
e. Details of tower protection (crash barrier) temporary i. If there is any other information that you think we
height limit gantry, etc. safety arrangement to be need to know, please include it.
provided if the works are close to the OHL.
f. Sheet piling protection details (If required). G. Other works.
g. TLP staff verified Cable / OHL clearance details. a. Proposed scope of work drawing to be submitted in
h. If any additional information required other than scale (1:1000) with DLTM coordinates incorporating
the above to be provided. any existing 400/132kV cables and OHL routes,
circuit names, cable joints and link box locations
F. Etisalat / Du Duct / Chamber Installation within the proposed working area.
a.
Proposed scope of work drawing should be b. Clearance from the proposed scope of any works,
submitted in scale (1:1000) with DLTM coordinates excavations and pilings to the 400/132kV cables
incorporating the Existing 400/132kV OHL and or the trough edge and the horizontal and vertical
cable routes, circuit names, and cable joints and clearance from the OHL to the proposed scope of
link box locations. work, and the horizontal clearance from the tower
b.
Clearance from the proposed scope of work foundation to the excavation edge.
or excavation edge to the 400/132 kV cable or c. ROW cross section details.
trough edge and horizontal and vertical clearance d. Method statement for the proposed work.
from the OHL to the proposed scope of work, and e. If the works are near or close to the OHL then
horizontal clearance from the tower foundation to provide clearance details of any equipment and
g. Any proposed road or road-widening over existing n. Joint site inspection from TLM personnel may be
duct banks, edge of the proposed road should show required to confirm the above details provided.
the existing cable duct bank edge. Note:-If any work has been carried out without a
If the duct bank is extended, then provide the DEWA NOC or there has been a violation of DEWAs NOC
details and end-coordinates. conditions during the work, then a clearance certificate
h. If the Proposed road edge is close to the cable may not be issued.
joint or link box locations, 4 corners coordinates of
the joint box, Horizontal clearance from the joint J. Requirements of as built drawings for
or link box to the road edge should be shown to 400/132kV OHL risings or Cable diversions
the drawing.
i. If any utility services or diversions are included in a. Clearance from the B/L/ROW/ Road edge to the
the proposed road work contract, then provide cable diversion to be marked on the drawing.
clearance details of the services, such as water, b. Cross section details of services crossings mainly
drainage, storm water, irrigation pipelines, Etisalat for water and other pressure pipe line crossings,
ducts, electricity HV and LV) crossing details, existing 132kV cable crossings and road crossings
and protection. should be provided.
j. Include details of any landscaping work included c. Attached a copy of the RTA NOC with the final As-
under the road project within the vicinity of the Built drawing along with the ROW cross section.
existing 400/132kV OHL or cables. d. Duct bank / Drilling portion including length and
k. Provide clearance from any road signal posts and GPS coordinates.
street light poles to the existing 400/132kV OHL or e. Directional Drilling profile details with GPS co-
cables. ordinates (Separately for each drilling).
l. If the 132kV Cable diversions or OHL raising are f. Cable schedule showing the section wise route
included under the road contract, then provide length.
separate As built drawings as per DEWA standard. g. Pilot and FO cable joint locations should be marked
(Standard requirements list attached). with GPS coordinates and detailed sections.
m. Contractors and consultants must ensure that back- h. Provide any cable route layouts inside substations.
filling works over the existing cable route, where i. Provide any updated substation layouts showing
the construction related works carried out over or new 132kV cable route along with existing ones.
within the vicinity of the 400/132kV OHL or cable j. Single line drawings should show any cables in duct
areas, and that no route markers are displaced, bank areas, protection with Inter lock tiles and
removed, or damaged during the work, if any. directly-buried areas.
This
DEWA
400/132kV
cables
NOC
is
fully
or
partially
issued
subject
to
the
following
conditions:
1. This NOC is not a blanket permission to start the work. should be removed. A steel protection barrier should to be provided for
2. Send prior notification to DEWA at least 2 working days in advance by fax link boxes in the vicinity of the road.
to 04 322 9095 or email tlm.supervision@dewa.gov.ae and confirmed with 23. Any existing spare ducts should be extended to the proposed road
the engineers telephone number given in the issued NOC (No-Objection widening or crossing area. If this is not possible, then new end to end
Certificate). spare ducts should be provided and maintained at least 1.5 metres either
3. Originals and copies of the NOC drawings approved by DEWAs TLM side of the proposed road edge. This is from the road shoulder edge or the
(Transmission Line Maintenance) department must be available at the road shoulder protection edge)
worksite (within the vicinity of the cable area), including trial-pit verified 24. Route markers should not be displaced or destroyed as they will be
drawings and method of statement. Sub-contractors are not allowed to replaced or reinstated in the same place or position after completion of the
work in the vicinity of DEWAs 132kV power, FO (Fibre-Optic), or pilot works with the pole or flush type and tiled area to be provided with the
cable routes without prior approval from DEWA TLM. flush type marker. Project owners are financially liable for their loss or
4. Responsible engineers, supervisors and approved safety officers should irreparable damage. Suitable route markers to be provided over the cable
be available at the site while working close to DEWAs ED services. route when asphalt road works involved subject to RTA approval.
5. Contractors should take all safety regulations and precautions are at their 25. Every drawing must be marked with GPS coordinates showing cable
own cost while working in the vicinity of DEWAs services and will be liable positions at every 50-metre interval and turning areas with protection,
for any damage as per local Act 06/2015. Action will be taken against profile details and cross-sections in relation to the permanent structures
violators and contractor as per the violations, black points or fines or landmarks to be provided after finishing the project. Drawings should
incurred. also include the status of live FO or pilot cable portions clearly marked with
6. Trial holes to be taken by hand excavation in presence of DEWA personnel GPS coordinates in the As-Built drawing, in case the power cable is
prior to start of construction work to identify and confirm clearance of abandoned.
services marked in the approved NOC and the presence of any more 26. All work must be carried out in presence of DEWA personnel during normal
existing cables not marked that need to be identified and verified by TLM DEWA working hours (0730-1430 hours). Any deviation must be agreed in
staff. The Party has to make additional trial pits as per the site conditions writing in advance. No work is allowed at night. However, in urgent cases
or any request from DEWA staff. After backfilling any trial pit, temporary night work is permitted within the approved revised method statement as
signboards should be installed above the cable route showing numbers, applicable as per site conditions.
types and depth of cables. Also the coordinates must be specified in the 27. No high-pressure pipe joints must not be located under or close to any
drawing for TP Locations. cables. The surrounding steel sleeve must be extended to both sides of the
7. Existing 132kv cables within the vicinity of proposed working area to be cable depending upon the diameter of the pipeline, this is to be approved
located and identified by digging trial pits, barricading, and fixing danger by DEWA.
signboards as per DEWA requirements and site conditions in the presence 28. The party who obtained the NOC from DEWA is only allowed to work at the
of TLM-LP (Transmission Line Maintenance Line Patrolling) staff. DEWA site. However, sub-contractors works can be allowed if previously
TLM Clearance will be provided to the contractor only after fulfilling the approved by the appropriate DEWA department.
condition. 29. Clearance from retaining walls, pilings or pillars must be at least 2.0m
8. Any machinery, construction equipment, excavators and other vehicles not away from any cable or trough. The works to be carried out after identify
allowed to work, move or park over the cable route at unmade area and the the cable/trough with coordinates by TLMs cable staff.
use of heavily vibrating compactors are prohibited. If any particular 30. Any deep excavation in close proximity to any cable or trough should be
locations require a cross over for the cables, then that area is to be provided with steel sheet piling and protection with de-watering
protected and a separate NOC must be obtained. arrangements along the cable route, after providing method of statement.
9. Cable corridors should not be enclosed by fencing. If the corridor is inside 31. Any proposed 400/132 kV cable installation, diversion, or in or out loop
the boundary of project area, then it should not be used as a storage area, must be a minimum of 100 metres. Clearance to be required from the
site offices, or for any other purpose existing nearest cable joint location to the proposed cable joint location, if
10. No road construction, -landscaping or other work should be carried out not the proposed cables to be connected to the nearest existing cable
where joints and link boxes exit and joint bays must able accessible at all joint. Contractors must take health & safety and precautionary measures
times. If any activity takes places within this area that is not mentioned in to safeguard power, pilot and FO cables during shutdown works for any
the approved NOC and drawings, then a separate NOC must be obtained LILO and Diversion works.
for it. 32. If any cable circuits are energised and could affect the proposed working
11. Any construction or structures in the DEWA corridor, such as for other area before completion of the work and during the validity of the NOC, then
utility services, manholes, or gullies, are prohibited. separate NOCs must be obtained to complete the remaining work.
12. Any streetlight poles, crash barriers, road signboards, or excessive filling 33. After obtaining general NOC for the project, separate NOCs to be obtained
on cable corridor are prohibited. Only grass or shrubs are allowed in the for the following: utility services installations, diversions, plantations,
cable corridor. Trees should be at least 5.0 meters away. tiling, piling, drilling, street lighting & signal foundations, chambers,
13. The minimum clearance for services such as cables, pipes and ducts must Manholes, gullies, RTU (Remote Terminal Unit) Cabinets /SCADA cable
be 1 (one) Meter away and 500mm above or below and no services lay on works, Hoarding boards, Meter Cabinets etc., if these details are not
top of the troughs. mentioned in the Project NOC drawing along with cross sections and
14. DEWA reserves the right to excavate the garden, grass, tiled area or road clearance of Transmission lines.
without any notification in case of emergency. Anyone undertaking tiling, 34. Entrance to DEWA substation and access to DEWA corridor should not be
gardening, and landscaping work should give an undertaking before blocked for the proposed project/work by any means temporary or
commencement of the work and obtain an NOC. permanently. Access way to DEWA substation, Cable/OHL corridor to be
15. Protection and backfilling must be specified on NOC drawings, Methods of arranged by the Developer, and the relevant authorities for routine
statement, and site instruction must be carried out under DEWA TLM patrolling and maintenance work.
supervision. 35. Proposed protection for the cable/trough, Pipelines, sleeve extensions,
16. All crossings of 132 kV cables and passing parallels require a separate new spare ducts, Duct extensions to be confirmed and verified by TLMD
cross section. Sections, protection and methods of statement for this must cable staff during or completing the particular works (before backfilling
be approved by DEWA in advance. No crossing is allowed over or under the area) and the verified details to be submitted along with the As-Built
cable joints or link boxes. drawings and completion certificates.
17. Micro tunnelling, thrust boring, and directional drilling should have a 36. Fibre hand shovels should be used for removal of sand inside the trough
minimum vertical clearance of 2.0metres from the bottom of cables or with live cables.
troughs and a horizontal clearance of 2.0metres from the edge of the cable 37. Contractor site engineers, supervisor staff, and machine operators should
or trough to the entry or exit pit. The drilling profile must be approved by attend TBT given by TLP Engineer as and when required.
DEWA TLM. 38. Working personnel and site agents are liable to receive any site
18. Micro tunnelling, thrust boring, directional drilling, piling and soil instructions by issuing stop work notices issued by DEWA representatives.
investigation will be approved only after all the services and clearances Working personnel and site agents must not ignore or behave improper
have been identified and verified with coordinates. If existing cables are in manner on receipt of these notices and must stop the work immediately.
HDD (Horizontal Directional Drilling) and not possible to locate through Failure to do so will be considered as serious violation.
trial pit, then atrial pit should be dug at a minimum of 1.0m below the 39. Contractors must notify DEWA after completion of all required works and
proposed excavation depth and confirm that the cable is deeper than the obtain a clearance certificate within 45 days. Clearance certificates will
proposed excavation or drilling depth. The method statement and shop not to be issued if the relevant conditions are not met.
drawing must be approved by DEWA before work is carried out. The 40. This NOC is valid for 6 months only, and should be revalidated 15 days
drilling location must be ensured as per the approved profile and before it is due to expire.
coordinates before starting the work by the TLM-TP supervisor. 41. DEWA reserves the right to stop the work, and review, suspend, or cancel
19. Shifting, slewing or exposing cables will not be permitted without an NOC the NOC in case of any violations of the above conditions or any observed
demonstrating explicit written permission. high risks to the network during work at the site or any emergency arises.
20. Separate NOC has to be taken from DEWA through RTA for the works
outside the building plot limit within the vicinity of the Transmission lines
such as shoring, piling, and anchoring, fencing access way to the building,
interlock tiling landscaping, or any other similar work.
21. Existing cables coming under the proposed roads crossing area shall be
provided with suitable protection along with spare ducts and temporary
road constructed on top of cables have to be removed once use is over.
22. Existing cables or troughs coming under or along the proposed road Transmission Lines Maintenance department
should be diverted and the abandoned portion of the cables or troughs Patrolling & NOC Section
Contact details
Location DEWA Warsan Office DEWA Hudaiba Office DEWA Warsan Office
2nd Floor 2nd Floor
1. Identification & Barricading: Existing transmission lines in the vicinity and within the proposed working area
should be identified by trial pits. Danger sign board needs to be fixed, and entire cable routes barricaded,
before starting the work at site. - Figure: 4.1.1, 4.1.2, 4.1.3
20cm 20cm
DANGER DANGER
132kV LIVE CABLE 15cm 132kV LIVE CABLE 15cm
BELOW BELOW
Rear view
20cm 20cm
DANGER DANGER
132kV LIVE CABLE 15cm 132kV LIVE CABLE 15cm
75cm
BELOW BELOW
75cm
Front view
Front view
Danger Sign Boad
Protection Slab details for road construction on top of the 132kV Trough / Cable
9. Parking installation: Parking (asphalted or c. Flush type cable route marker should be installed
interlocking tiles) are allowed above the existing over the cable route at maximum interval of 50
132kV cables in trough or direct buried Fiber optic metres for straight cable run. Figure: 1.4.7 (Pg. 20)
or pilot cables and each of the the following
requirements and additional protections should 10. Road widening: Existing protection and spare
be both met and provided. ducts should be extended to any proposed road
a. Providing of protection and spare ducts as shown widening or crossing areas. if this is not possible,
in the Figure: 4.1.8 & 4.1.9. then new end-to-end spare ducts must be
b. No part of any parking area should be constructed provided, and maintain a minimum of 1 metre
over underground cables joint and flush type Link from either side of the proposed road edge.
boxes. Figure: 4.1.10
Protection Slab details for road Widening on top of the 132kV Trough / Cable
11.
No Blocking of Access: Entrances to DEWA disposed immediately and the site cleaned
substation or access to DEWA Corridor should before demobilisation. Figure: 4.1.11, 4.1.12, 4.1.13
not be blocked by the new project or work by any
means, whether temporary or permanent. 13. Route markers: Route markers should not be
displaced or destroyed otherwise it will be
12. Backfilling: Backfilling of transmission cable charged for and will be replaced or restored in the
routes should be carried out as per DEWA same place or position after completion of the
standard. Backfilling materials, excavated soil work with a pole- or flush-type marker. Any tiled
and any other materials used for construction areas should be provided with flush-type route
works shall not be left at the site. All stored markers after completion of the works.
or dumped materials and any soil should be Figure: 1.4.6, 1.4.7 (Pg 20)
Fig 4.1.11
Placing of cable Protection tiles during Fig 4.1.12 Placing of electrical warning tape during
backfilling backfilling
CBCH-INDS pilot finally back filled CBCH-INDS pilot finally back filled
1. Height limit gantries: Temporary height limit gantries about 5.5 - 6 m from ground level must be installed for
all machinery, such as diggers or cranes, at all working locations, along with danger sign boards. Figure: 4.1.14,
4.1.15
Fig 4.1.14 - Temporary Height limit gantry under OHL at machinery working locations
PERMITTED PERMITTED
HEIGHT - __ M HEIGHT - __ M
Fig 4.1.15
Fig 4.1.16
Minimum Horizontal Clearence From 400 / 132kV OHL Tower Foundation To The Edge Of The Road,
When The Line & The Road Is Running In Parallel
Minimum Vertical Clearence From Bottom Conductor of 400 / 132kV O / H Line To The Top Of The Road Level
For High Way / Secondary Road (considering a maximum conductor temperature of 80 degree Celsius)
1.
Existing cable identification: Existing compactors are prohibited.
Transmission lines to be identified in the vicinity If any particular locations are required to cross
of new cable installation area, by trial pit and fix over existing cables, then that portion requires
danger sign board along the cable route and the a separate NOC and the cable route must be
area should be barricaded before starting the protected for the crossing area. Only manual
work at site. Figure: 4.1.1, 4.1.2, 4.1.3 (Pg no - 44) excavation is allowed. Figure: 4.1.4 (Pg no - 45)
2.
No Machinery Excavation: No machinery, 3. Service Clearance: Minimum clearances of services
construction equipment, excavators or any such as cables, pipes and ducts etc. must be at least
vehicles are allowed to work, move or park over 1 (one) Meter away and 500 mm above or below
the cable route and the use of heavy vibratory with no services laid on top of the troughs.
Minimum Horizontal Clearence For 11kV / 33kV / Etisalat / DU Duct and Pipe Laying With Parallel 132kV Cable In Trough
6. Crossing under trough: 132kV troughs and directly-buried 9. Entrance: Entrance to DEWA substation and access
cable should be protected as per the approved method to DEWA corridor should not be blocked for the
and duct banks should be installed by the open cut proposed project or work by any means, either
method if the trench width exceeds 1.5 m underneath temporarily or permanently
any cable troughs of 6 m length. (Figure: 4.2.4)
10. Backfilling: Backfilling of transmission cable routes
7. GPS coordinates: For crossing existing 132kV cables should be carried out as per the DEWA standard.
by the HDD method, all existing transmission services Backfilling materials, excavated soil and any other
should be identified by trial pits. HDD entry and exit materials used for construction works must not be
pit locations should be marked by GPS coordinates left at the site. Any stored or dumped materials
and verified by a DEWA-TLP supervisor during the TP or soil must be disposed immediately and the site
verification and before starting the construction work. cleaned before demobilisation. (Figure: 4.1.11,
4.1.12, 4.1.13 - Pg. 50)
8. Diversion / LILO cable length: New cable lengths
for existing cable diversion and LILO should not be 11. Route markers: Route markers should not be
less than 100m from joint to joint or joint to cable displaced or destroyed otherwise it will be charged
termination at GIS. for and will be replaced or restored in the same place
1.
Height limit gantries: Installation of temporary 8.
Parking of vehicle: Parking of any vehicles over
height limit gantries should be about 5.5 - 6 m from cable routes or under OHL corridor transmission
the ground for all machinery, such as diggers and services is prohibited.
cranes, in working locations, along with danger
signboards. (Figure: 4.1.14, 4.1.15 - Pg 51 & 52) Fig 4.2.6 Minimum horizontal clearance requirement
for excavations near tower foundation
2. Crash barrier: Temporary concrete crash barriers
need to be installed around nearby tower
foundations. (Figure: 4.1.16 Pg. 53)
5.
Earth conductor protection: Tower foundation
earth conductor should be protected while
excavating near tower foundations. EDGE OF THE EXCAVATION
EXISTING G.L
5.0mtr.
Minimum Horizontal Clearence From 132 / 400kV / O / H Line Tower To Prop. Trench Excavaion
1. Existing cable identification: Existing Transmission de-watering arrangements along the cable route,
lines should be identified in the vicinity of new after providing a method statement. (Figure: 4.3.1)
cable installation area, by trial pit. Danger 6. Substation Access: Entrance to DEWA substations
signboards should be posted along the cable route and access to DEWA corridors should not be blocked
and the area barricaded before starting work at the for the proposed project or work by any means,
site. Figure: 4.1.1, 4.1.2, 4.1.3 (Pg no - 44) whether temporary or permanently
2. No Machinery Excavation: Machinery, 7. Cable shifting/slewing: Any shifting, slewing or
construction equipment, excavators and any exposing cables will not be permitted without
other vehicles are not allowed to work, move NOC explicit written permission. Exposed cables
or park over the cable route and use of any must be protected in wooden boxes or split duct
heavy vibratory compactors is prohibited. If any after wrapping with hessian cloth and supported
particular locations are required to cross over properly. (Fig.4.2.2 & 4.2.3 - Pg 59 & 60)
the existing cables, then that portion requires
Fig 4.3.1 Sheet piling protection for 132kV cable from
a separate NOC be obtained and the cable route
trench collapse
protected at the crossing area. Only manual
excavation is allowed. Figure: 4.1.4 (Pg no - 45)
3. Service Clearance: Minimum clearances of
pressurised water or irrigation should be at least
3 metres distant from and at least either 500
mm above and below with no services laid above
the troughs. Figure: 4.2.1 (Pg no - 57)
4. DEWA Corridor: Any construction or structures in
the DEWA corridor, such as RTUs, manholes, or
gullies, are prohibited
5. Deep Excavation: Any deep excavation in close
proximity to the cable or trough should be 132kV cable trough 132kV cable corridor
provided with steel sheet piling or protection with supported by H beam (protected by sheet piling
from collapsing)
4. Sheet piling: Sheet piling or sand bags to be 10.2 A minimum horizontal clearance of 50m from
provided, while excavating near the tower tower foundation to be ensured, for laying any
foundation to avoid collapse of sand. (Figure: proposed metallic pipe services at a nominal
4.2.7 Pg 62) diameter between 180 - 450mm, as per DEWA
technical specifications.
Earth conductor protection: Tower foundation
5.
earth conductor should be protected, while 10.3 There must be a minimum horizontal clearance
excavating near the tower foundation. of 100m from the tower foundations when
laying any proposed metallic pipe services at
6. Access road: DEWA patrolling access road must a nominal diameter more than 450mm, as per
be repaired by the contractor, if damaged. DEWA technical specifications.
1. Existing cable identification: Existing Transmission equipment, site offices, or as a parking area.
lines should be identified in the vicinity of new Figure: 4.4.1
cable installation areas, by trial pits and fixed 5. Access Road: For any access road to the building,
danger signboards along the cable route and area the necessary protection should be made for the
to be barricaded, before starting work at the site. existing cable route as per the approved NOC.
Figure: 4.1.1, 4.1.2, 4.1.3 (Pg no - 44) 6. Shoring and Anchoring: Shoring and Anchoring
2. No Machinery Excavation: Machinery, construction should be at a minimum of 2.0 metres away from
equipment, excavators and any other vehicles are the existing cable or trough edge. Figure: 4.4.2
not allowed to work, move or park over the cable
Fig 4.4.1 Transmission cable (400kV, 132kV) route
route and use of any heavy vibratory compactors is should not be enclosed by fence and no storage of
prohibited. If any particular locations are required any material over cable corridor
to cross over the existing cables, then that portion
requires a separate NOC and the cable route must
be protected at the crossing area. Only Manual
excavation is allowed. Figure: 4.1.4 (Pg no - 45)
3. Undertaking: DEWA reserves the right to excavate
the garden, grass or tiled area and road without
prior notice in case of emergency. Owners of the
tiling, gardening or landscaping work should give
an undertaking before commencement of the
work. Trees should be at least 5metres away. A NOC
is required for this. Figure: 4.1.5 (Pg no - 45)
4. Enclosing by fence: Cable corridor should not
be enclosed by fence and if the corridor is inside
boundary of project area, then should not be used
as a storage of excavated or construction materials, Fence not enclosing the cable route
Note:
Width of the OHL corridor
varies from one to another
tower location.
20m - Minimum horizontal
clearance from 400kV outer
conductor
15m - Minimum horizontal
clearance from 132kV outer
conductor
1. Construction works inside corridor: Construction 3. Access Road: The DEWA access road along the line
of buildings and any other activities are not allowed should not to be disturbed or damaged.
within the DEWA OHL Corridor. The OHL corridor 4. Vehicle parking: Heavy machinery, vehicle or other
shall be confirmed from the TLM NOC centre. equipment are not allowed to park under or near
(Figure: 4.4.3) the overhead line.
2. Miscellaneous works inside corridor: Shoring, 5. Height limit gantry: Temporary height limit
walls, fencing and interlocking are not allowed gantries should be installed in case vehicles and
within the OHL corridor. OHL corridor shall be equipment need to pass or approach the OHLs.
confirmed from TLM NOC centre.
3. Prior intimation: Advance notice should be given to Clearance: Micro-tunnelling, thrust boring, pipe-
6.
DEWA 2 days prior to start the work and works to be jacking, and directional drilling should have a
carried out in the presence of DEWA TLP supervisor. minimum vertical clearance of 2.0m from the
(Format attached Pg.no - 29) bottom of the cable or trough and the horizontal
clearance of 2.0m from the edge of the cable or
4. No Machinery Excavation: Machinery, construction trough to the entry or exit pit. The drilling profile
equipment, excavators and any other vehicles are should be approved by DEWA TLM.
not allowed to work, move or park over the cable
route and use of any heavy vibratory compactors is 7. Trough protection: While laying steel sleeves and
prohibited. If any particular locations are required pipelines underneath troughs for crossing by the open
to cross over the existing cables, then that portion cut method, 132kV cable troughs should be braced
separate NOC should be obtained and the cable with suitable steel supports Figure: 4.2.4 (Pg no 60)
route protected at the crossing area. Only Manual
excavation is allowed. Figure: 4.1.4 (Pg no- 45) 8. Entry / Exit pit: While making entry or exit pits close
to 132kV cables for drilling, 132kV cables should be
protected by sheet piling. (Figure: 4.5.1)
1. Height limit gantries: Installation of temporary while excavating near the tower foundation to avoid
height limit gantries should be about 5.5 - 6 m from collapse of sand. (Figure: 4.2.7) Pg 62
the ground for all machinery, such as diggers and 5. Earth conductor protection: Tower foundation
cranes, in working locations, along with danger earth conductor to be protected, while excavating
signboards. (Figure: 4.1.14, 4.1.15 - Pg no 51 & 52) near the tower foundation.
2. Crash barrier: Temporary concrete crash barriers 6. Access road: DEWA patrolling access road must be
need to be installed around nearby tower repaired by the contractor, if damaged.
foundations. (Figure: 4.1.16 - Pg 53) 7. Removal of unwanted materials: Leftovers, waste
3. Excavation clearance: Any excavations near the and any other debris should be removed from the
concrete foundation of the tower must be at least OHL Corridor, after the completion of work.
5 metres horizontally distant from them. (Figure: 8. Parking of vehicle: Parking of any vehicles over cable
4.2.6) Pg 61 routes or under OHL corridor transmission services is
4. Sheet piling: Sheet piling or sand bags to be provided, prohibited.
1. Existing cable identification: Existing Transmission duct laying above the cable trough is not allowed as
lines should be identified in the vicinity of new cable this will obstruct opening of trough cover.
installation areas by trial pits and danger signboards 6. Cable crossing protection: Any crossing of duct
fixed along the cable route and area to be barricaded bank above Existing direct buried Transmission
before starting work at the site. (Figure: 4.1.1, 4.1.2, cable existing cable to be protected by spilt duct
4.1.3 - Pg no - 44) and surround concrete with spare duct to ensure
2. No Machinery Excavation: Machinery, construction that no load will be transferred to the cables.
equipment, excavators and any other vehicles are Figure: 4.1.8 (Pg no - 47)
not allowed to work, move or park over the cable 7. Crossing of new Duct bank: While crossing
route and use of any heavy vibratory compactors is of new duct bank below the existing direct
prohibited. If any particular locations are required buried Transmission cable, said cable should be
to cross over the existing cables, then that portion protected and supported. (Figure: 4.2.2 & 4.2.3)
requires a separate NOC and cable route must (Pg no - 59 & 60)
be protected at the crossing area. Only Manual 8. Cable protection for open cut method: Existing 132kV
excavation is allowed. (Figure: 4.1.4 - Pg no - 45) trough and directly-buried cables should be protected
3. Minimum clearances: Minimum clearances of services as per the approved method statement while
such as cables, pipes and ducts etc. to be 1 (one) Metre installation of duct banks by the open cut method
away and 500 mm above or below and no services lay (if trench width exceeds 1.5m) underneath of cable
on top of the troughs. Figure: 4.2.1 (Pg no - 57) trough of 6 metre length. Figure: 4.2.4 (Pg no - 60)
4. Parallel installation: New services and duct laying 9. Service verification: All services to be identified by
is not allowed to run parallel exactly above or below trial pit if duct laying by HDD method. GPS coordinates
the existing 132kV cables and troughs, irrespective to be provided for TP locations and entry and exit pits
of any vertical clearance but are allowed if adjacent, for the drilling. Before starting the drilling works, the
provided the clearances are complied with as per the coordinates shown in the approved NOC for entry and
approved NOC. exit pits and trial pit locations should be confirmed by
5. Trough cover opening: Crossing of new services or a TLP supervisor.
Note: Width of the OHL corridor varies from one to another tower location.
No Tree Plantation Allowed Inside DEWA Transmission OHL Corridor
a) Height limit gantries: Temporary height limit gantries about 5.5 - 6 m from ground level must be installed
for all machinery, such as diggers or cranes, at all working locations, along with danger signboards. (Figure:
4.1.14, 4.1.15 - Pg no 51 & 52)
Fig 4.7.2
Minimum Clearance requirement for Lighting Pole Installation from OHL conductor
g)
Parking of vehicle: Parking of any vehicles
over cable routes or under OHL corridor
transmission services is prohibited.
Zone / Location
Affected Circuit
Please follow () marked instruction very strictly to avoid work stop notice
1. Prior intimation to be given DEWA TLM for works commencement at least 2 working days in advance in the work
supervision request format by fax 04-3229095 or by email tlm.supervision@dewa.gov.ae
2. NOC with approved method of statement. Trial pit verification/OHL clearance details & drawings must be available at work
site throughout the project completion.
3. NOC is valid for 6 months only & should be revalidated within 15 days before expiry by submitting the original stamped NOC
copy.
4. Responsible Engineer/Supervisor should be available at site while working close to Tr. Lines.
5. Cross-sectional drawings with horizontal and vertical clearances & method of statement to be approved by TLMD for cable /
OHL crossing works.
Works should be carried out during DEWA working hours only. Works at night, holidays & beyond office hours are not
6.
allowed. Special approval to be obtained for emergency and very urgent works with justification to work beyond working
hours.
7. Trial holes to be taken to locate existing 400/132KV Cable at proposed work area by hand shovel excavation only.
8. Before starting of drilling/boring/shoring/piling work, site location shall be confirmed by GPS coordinates and approved
method of statement to be ensured by DEWA TLM Supervisor.
9. Height limit gantry/Danger sign board/safety & crash barrier to be provided for the Cable/OHL route/tower at working area.
Existing route markers can be removed only after taking GPS co-ordinates and reinstalled at the same location after the
10.
completion of work as per the previously taken GPS co-ordinates. Displaced /damaged/missing route marker/bollard to be
re-instated at the previous location as per the GPS coordinates.
11. New 400 / 132 kV Cable and OHL circuit is energized in the working area and shall obtain separate NOC from TLM for
remaining works showing the newly energized Cable/OHL circuits.
12. Parking of Vehicle/Heavy machinery movement, excavated soil dumping, material storage should not be carried out over
the Cable route, Joint & Link box Location/under OHL.
13. Existing cables coming under the proposed road crossings shall be provided with suitable protection along with spare ducts
(if existing available then to be extended).
14. Steel sheet piling/shoring with dewatering arrangement should be provided for the deep excavation works in the close
proximity of the Transmission lines after the approval of location and method of statement.
15. Separate NOC to be obtained for the utility services/street lighting, signal, plantation works, dewatering works and other
works which are not included in the issued NOC.
16. Adequate manpower to be arranged while working near to the 400/132KV Cable/OHL network.
17. The undersigned (contractor/utility depts. representative) is agreed to follow all the above-ticked instructions and any
failure will cause DEWA to issue Stop Work Notice. And necessary action shall be taken as per law 06/15.
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WORK DESCRIPTION:
REMARKS:
ISSUED TO (CONTRACTOR STA FF) ISSUED BY (DEWA SUPERVISOR) DEWA ENGINEER
Transmission Maintenance Department - Fax No. 04-3229095 Tel No. 04 -3221546/04-3221500 TP/TMD/TLM/LP&N/QP-01.A02
Endorsed By:
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Date:
(Sr.
Manager
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Dy.
Sr.
Manager
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Manager)
Form-15-TBT-H&S-June
2015
6.2.1.1
Action against violators who fall under
Category A:
If contractor performs violation at site
repeatedly and accumulates say 18 black
points (within a period of one year), as per the
violations of NOC conditions and protective
regulations, following action shall be taken as
mentioned below,
A1. Contractor works at violated locations will
be stopped.
A2. Inform the utility and DEWA depts. about
the Contractors violation and request
for their action against the violated
Contractor.
A3. Meeting with clients (DEWA or Private),
Contractors & Consultants to list actions
to avoid repeating of violations.
A4. Action Plan for safe construction work in
close vicinity of 400 / 132 kV OHL/ Cable
should be prepared by the Contractor
/ Consultant, and Utility / DEWA dept.
and will submit to TMD/TLM for review/
approval.
A5. Warning to be issued to Site In charge.
6.2.1.2
Action against violators who fall under and accumulation of black points reaches 48 (within a
category B: period of one year), following action shall be taken as
mentioned below,
If accumulation of black points reaches 35 or damage
of 400/132kV Cable/Ohl without tripping (within a C1. All works of the particular project will be stopped.
period of one year), following action shall be taken as C2. A ll issued NOCs will be cancelled for the
mentioned below, particular project.
C3. Stop issuing new NOCs for the period of 3
B1. All works of the particular project will be stopped. months to the involved Contractor.
B2. All issued NOCs will be suspended for C4. Inform the utility and DEWA depts. about the
the particular project until fulfilling the Contractors violation and request for their
requirements specified in B5. action against the violated Contractor.
B3. Inform the utility and DEWA depts. about the C5. Meeting with clients (DEWA or Private),
Contractors violation and request for their Contractors & Consultants to list actions to
action against the violated contractor. avoid repeating of violations.
B4. Meeting with clients (Authority or Private), C6. For resumption of work, either new Contractor /
Contractors & Consultants to list actions to DEWA approved Contractors to be appointed or
avoid repeating of violations. Replace the Project Manager, Project Engineer,
B5. Replace the Project Engineer, Safety Engineer, Safety Engineer, and Site Supervisor of the
and Site Supervisor of the project. CVs of the project. CVs of the newly appointed staffs will
newly appointed staffs will be submitted to be submitted to TMD/TLM for review/approval.
TMD/TLM for review/approval. C7. Action Plan for safe construction work in close
B6. Action Plan for safe construction work in close vicinity of 400 / 132 kV OHL/ Cable should be
vicinity of 400 / 132 kV OHL/ Cable should be prepared by the Contractor / Consultant, and
prepared by the Contractor / Consultant, and Utility Utility / DEWA Dept. and will submit to TMD/TLM
/ DEWA Dept. and submit to TMD/TLM for review / for review / approval. Also New NOC application
approval to avoid repetition of violation /damage. for the particular project shall be applied
through proper channel.
6.2.1.3
Action against violators who fall under
category C: Furthermore works can be resumed subject to fulfilling
above mentioned requirements and agreements as per
If damage of 400/132kV Cable/OHL occurs with tripping respective categories.
For any clarification related to any information mentioned in the Hand Book, please send your queries / comments
to the following contact details:
Email : tlm.supervision@dewa.gov.ae
Website : www.dewa.gov.ae