Electrical Power Cable Short Circuit Current Capacity

How Calculate Cable Short Circuit Current from Short Circuit Current from Table?

You may find the short circuit current for a particular type of cable for a specified period of time from your cable manufacturer’s provided catalogue. For example the below table is showing different sizes from 16 square mili-meter to 2500 square mili-meter of cable in first left column and time duration from 0.1 second to 5 second in next 10 columns.

Cable Basic Parameters Resistance, Inductance and Capacitance

Cable Basic Parameters Resistance, Inductance, and Capacitance

What Happen If Cables Placed In Magnetic Metal Conduit

What Happens If Cables Placed In Magnetic Metal Conduits 

Do we know what happens if cables are in a magnetic metal conduit? Yes, at least we know that in any circumstances, the individual phase of an AC (alternating current) circuit is in a separate magnetic metal conduit. 

ARMOUR EARTHING ASSEMBLING FOR SINGLE CORE CABLE

Armour Earthing Assembly for Wire Armour Single Core Cable

33kV Cable Earthing System

Cable armour earthing is important for medium voltage (MV), high voltage (HV) and extra high voltage (EHV) system. 

Our discussion on this article is limited only single core plastic or paper cable wired armour earthing procedure for medium voltage (MV) system or 7.2 kV to 36 kV ranges.

The crystal clear step-by-step assembly figure shown the complete procedure of earthing system for wired armour cable.

If you follow the shown 9 step carefully, we hope you will be able to assemble the cable armour earthing successfully.

9 Step to Earth Cable Armour  

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1. First of all remove the over-sheath according to the dimension given the appropriate manufacturer Installation Instruction, Remove the armour according to dimension as per shown in the drawing. Clean the end of the over-sheath for a length of 250 mm.
2. Then slide the outer sleeve over the cable, and disassemble the clamping rings. Slide one clamping ring lug-downwards over the cable as shown in the figure 2.
3. Following the figure no-3 spread the armour wires as shown in the drawing and screw the other clamping ring loosely to the lugged clamping ring.
4. Install the termination in accordance with the Installation Instruction of termination manufacturer. Pass the end of the earth lead down through the clamping rings and connect it to one lug of the clamping ring. Tighten the clamping rings, refer to figure no-4.
5. With a small overlap and slight tension wrap two layers of sealant tape round the overs-heath for a length of 50 mm, just below the armour wire ends. Wrap two layers of sealant tape round the earth conductor so that it will be just below the armour wire ends. Attach the earth conductor to the other lug of the clamping ring as figure-5.
6. As shown in figure-6, bend the armour wires back and bind the ends to the over-sheath with a wire binder or plastic tape. noted that all sharp wire ends must be covered with plastic tape.
7. With a slight tension and small overlap wrap two layers of sealant tape over the lower end of the termination for a length of 50 mm.
8. Position the top end of the outer sleeve level with the top of the sealant tape. Shrink it into place starting at the center. Shrink the lower end first and work towards the upper end.
9. Yes, you have done; installation of earthing assembly for armour is completed.

This is the basic instruction for cable armour earthing, to do it physically you must follow the manufacturer installation instruction and necessary safety code. If it is helpful, then share with others to help them. 

7 Step: How Find Cable Fault Location

How to Find Underground Electrical Energy Transmission Lines Cable Fault?

Finding the faulty point of an underground cable doesn't have to be like finding a lost item on the street. There are many faults locating methods depending on who finds the fault, and how he wants to find it -detection technologies are now much easier to find the cable fault, also important is the technique applied that makes the task much easier and less time-consuming. However, we can say that there is no single method or combination of methods that is universal. Skilled technique and proper tool selection is the major key point to finding the cable fault more easily and within a minimum time.

Types of Cable Faults

Thermosetting and Thermoplastic: Cable Insulation

Thermosetting and Thermoplastic:  Cable Insulation

PVC-insulated cables are not going to be called pvc cables anymore they are thermoplastic insulated cables and rubber cables are thermosetting! The use of the terms thermoplastic and thermosetting is the solution to the problem of an ever increasing number and variety of materials and blends available for the manufacture of cables. 

Underground Power Cable Site Test after Installation

Fig- Cable High Voltage Testing Kit

Site Test or Pre-commissioning Test Just after Underground Power Cable Installation

Many cable failures are the result of poor installation practices; so, all new installations should be thoroughly tested before they are put into service. Since the cable itself will have been tested at the factory, on-site testing of newly installed cables focuses on identifying localized problems that have occurred during installation. 

Site test after installation of the underground power cable is required to confirm that the line is installed correctly and there is no damage during laying.

POWER CABLE TERMINATION AND SEALING

Power Cables Termination and Sealing End Requirements

The servicer should terminate and connect up the power cables in accordance with diagrams or details approved by the employer Engineer. 

Considering the following requirements, power cable along with others controlling and communication cable sealing end should be terminate in an adequate manner.

Underground Power Cable Termination Coupling With Over Head Line

List of Cable and Cable Accessories Manufacturer Companies

XLPE Power Cable

Cable and Cable Accessories Manufacturer Companies in the world

• Europian Cable and Cable Accessories Manufacturer Companies list

• Arnocanali - Producers & distributors of plastic & aluminium cable trunking, mesh trays, components for conditioning systems & more.
  https://www.arnocanali.it/
  
• Aros Quality Group AB - Produces transformers, cables, plastic injection moulding, and metal stamping.
  https://www.aqg.se
  
• Batt Cables plc - UK cable supplier and distributor including, computer cable, power cable, network cable, electrical cable and accessories.
  http://www.batt.co.uk/

PARTIAL DISCHARGE TESTING OF POWER CABLE

Partial Discharge (PD) in Electrical Power Cable:

Why PD?

No matter way where you are an engineer or a technician for electrical power cable, you need a piece of pretty good knowledge about Partial Discharge or shortly PD to understand your cable life or the possibility of unwanted cable faults. You may gather knowledge about PD by watching video clips on YouTube or reading a blog or article about PD.

Introduction of Partial Discharge (PD):  

Partial discharge (PD) is one of the most important factors for a power cable system. The partial discharge measurement methods of assessing the quality of the insulation of power cable systems, especially for extruded insulation materials.

Where Partial Discharge Occur:

We can think of partial discharge for cable systems from two major points of view:

01. Partial Discharge within the whole cable

02. Partial Discharge in an individual              location

Partial Discharge Measurement:

 

Normally major factory test carried out on the insulation of the whole drum of extruded cable is the partial discharge test. This is usually done at power frequency, but can also be carried out at very low frequency and at some voltage significantly higher than normal working voltage to ground. PD test is a very sensitive method to find out very minor failures such as little void or skip of insulation layer during manufacturing time.

But this factory test is not sufficient for the end users of the cable systems, during cable shipping, cable installation, cable jointing, and termination; cable insulation may damage or crack. Minor damage or crack is not possible to find out during commissioning or energizing time. After a little longer time this defect increased slowly and finally cracked. By statistics from the cable systems, most of the cable faults occur in cable jointing and termination point.

For Better Results:

So it is better to observe the magnitude and phase of the partial discharge signals and how they vary with increasing and then decreasing test voltage, results will disclose information on the type and position of the defects and their probable effect on cable life.

Finally in conclusion we can say, if the cable system can be tested in the field to show that its partial discharge level is comparable with that obtained in the factory tests on the cable and accessories, it is the most convincing evidence that the cable system is in excellent condition.

Cable Parameters: Insulation Resistance,Charging Current, Dielectric Losses

Cable Parameters: Insulation Resistance, Charging Current, Dielectric Losses

Before we formulated cable basic parameters resistance, inductance, and capacitance, now we will try to 3 more parameters like Insulation Resistance, Charging Current and Dielectric Losses.

Cable Insulation Resistance:

Using the following formula you can calculate insulation resistance in mega-ohm per kilometer of cable, to do this you consider the insulation material, diameter of cable including a semiconductor layer, and the diameter of the insulated core.

R =K In (D/d )  MΩ/km

Where

R = Insulation resistance in MΩ/km;

K = Constant depends on the insulation material;

d = Diameter of the conductor in mm including the semiconducting layer;

D = Diameter in mm of the insulated core;

MΩ- mega ohm, km- kilo meter, mm- mili meter.

Cable Charging Current:

The charging current is the capacitive current that flows when AC voltage is applied to the cables as a result of the capacitance between the conductor and earth, and for a multi-core cable in which cores are not screened, between conductors. The value can be calculated from the following equation.

IC = Uo ωC 10^-6   A/km

Where

IC = Charging current in Ampear/km;

Uo =Voltage in volt between phase and earth;

ω= 2 π f (π=22/7, f= frequency in hertz) Hz;

C= Capacitance in micro-farad per kilo-meter to neutral;

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Cable Dielectric Losses:

To calculate the dielectric losses of an AC cable are proportional to the Capacitance, the frequency, the phase voltage and the power factor. The value in watt per kilo-meter per phase can be calculated from the following equation.

WD = 2 π f C Uo² tanδ 10^-6   watt/km/phase

Where 

WD = Dielectric losses in watt/km/phase;

f = Frequency in hertz;

C = Capacitance in micro-farad per kilo-meter to neutral;

Uo = Voltage in volt between phase and earth;

tanδ=Dielectric power factor.

What Happens If Water Enter Into Power Cable

How Water Enter Into Power Cable and Damage it?

Fig: 400kV underground power cables laid for transfer power from a power plant to grid substation.

What actually happens if water or moisture entered into the power cable?

We who are engaged with power cable management everyone very concuss to prevent enter water or moisture into cables. In the design and production line, they take some options to prevent moisture enter into cables; similarly, the cable installation and storage team also take tight action to prevent water or moisture enter into the cables. 

Cable Conductors Materials:

Widely used power cable conductors materials are Copper and Aluminum. 100% pure Copper and 99.5% or better pure Aluminum is used for better performance power cable conductor. A small amount of impurity may reduce a large percentage of conductivity. Silver is a very good conductor, but high cost and extreme softness is the obligation to use as wide scale. Compare to Copper Aluminum is inexpensive and softer.

Aluminum Uses in Power Cable:

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Many Copper conductors also use Aluminum as an armoured or metal sheath. Aluminium is very much sensitive to water in insulated power cables. So, the presence of water in Aluminum causes several problems. In Aluminum, if there is water in absence of Oxygen, chemically there will be hydrolyzing. 

Aluminium and Water Chemical Reaction:

The chemical reaction of Aluminum and water will be as follows:

2 Al + 6 H₂O   =   2Al(OH)₃ +3H₂  

So, if water entered into having Aluminum in the insulated power cable, in absence of Oxygen Aluminum and water chemically combine and produce Aluminum-Hydroxide and Hydrogen gas.

Aluminum Hydroxide:

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Aluminum Hydroxide is a white and powder type materials having a very good insulating character that degrades the conductor conductivity.

This is the theoretical and chemical reaction of water present inside the cable. Moreover, water presence in the vicinity of the cable for a long time may cause cable damage shortening the cable lifetime and unexpected breakdown may happen.

 

History of Electricity in Bangladesh

Bangladesh: Developing every day every moment

History of First Electricity Uses in Dhaka even Bangladesh:

Bangladesh borne in 1971, but electricity utilization started in this region as a part of India before creation Bangladesh. First electricity switched on 7 December 1901 in Ahsan Monjeel, the residence of the Nawab of Dhaka. Latter on Dhanmondi powerhouse was set up and the journey of commercial distribution started in 1930.

Brief History of Electricity In Bangladesh:

Up to the partition of the country and independence of India and Pakistan in 1947, electricity generation and distribution was authorized by some private companies in this region. Electricity facility was limited within 17 provincial district urban area and of course only for nighttime. Total power generation capacity was then only 21 MW for East Pakistan; the most privileged Dhaka city used two 1500kW generators to supply electricity.

To improve the power supply situation, the government of Pakistan created Electricity Directorate in 1948 and issued an ordinance in 1959 to form WAPDA (Water And Power Development Authority) to take over all electrical systems from the private sector to the Government sector. As a result, this organization got more autonomy and basic infrastructure developed during this time. From 1960 to 1970 power generation increased from 88MW to 475MW, Dhaka-Chittagong 132kV transmission line network, shiddirgonj, Khulna, Chittagong power plant and Kaptai dam started.

After independence of Bangladesh in 1972, the government realized to boost up the power sector and create BPDB (Bangladesh Power Development Board). The achievement the highlight of BPDB considering time period from 1972 to 1995 is: power generation capacity 2818 MW; high voltage transmission line network 132 kV 2469 km & 230 kV 419 km; highest voltage 230kV capacity transmission line of the country East-west (Tongi-Ishurdi) interconnector is switched on in December 1982. BPDB created an electricity facility in most of the district city area, but the government had to make sense that for developing the whole country electricity need in a rural area, especially for irrigation. 

So, the government created REB (Rural Electrification Board) in October 1977 who works for electrification in a rural area all over the country through PBS (Palli Bidyut Samity) except major district towns.

To segregate electric supply within Dhaka city from the jurisdiction of BPDB, DESA (Dhaka Electric Supply Authority) was created in 1992, but in latter DESA abolished and formed two company DESCO (Dhaka Electric Supply Company) and DPDC (Dhaka Power Distribution Company). 

Not only for Dhaka but also to improve consumer services and reduce losses for all over the country government rearranged and created different companies and organizations in the power sector many times. The major company and organization under the Ministry of Power, Energy and Mineral Resource in Bangladesh is as below:

List of Electricity Utility Organizations in Bangladesh:

BERC (Bangladesh Power Regulatory Commission)

BPDB (Bangladesh Power Development Board)

APSCL ( Ashuganj Power Station Company Limited)

EGCB (Electricity Generation Company of Bangladesh)

NWPGCL (North-West Power Generation Company Limited)

IPP (Independent Power Producer)

RPCL (Rural Power Company Limited)

PGCB (Power Grid Company of Bangladesh)

DPDC (Dhaka Power Distribution Company Ltd)

DESCO (Dhaka Power Supply Company Ltd)

WZPDCL (West Zone Power Distribution Company Ltd)

SZPDCL (South Zone Power Distribution Company Ltd)

BREB (Rural Electrification Board)

PBS ( Palli Bidyut Samity)

OUTDOOR STRUCTURE FOR HIGH VOLTAGE POWER CABLE

Fig-A Typical Outdoor Grid Substation

Outdoor Steel Structure Design and Installation for HV & EHV Power Cable

The structures shall be designed to carry cable sealing ends, cables and cleats, earthing bars, earth disconnecting links, sunshields and other fittings  should be followed an adequate design manner.

Each sealing end should be provide with a separate structure which be positioned so as to align with the phase center distances of the substation equipment but not less than the minimum electrical and safety clearness as international standard like specified in BS 162.

All structures should be equipped with a suitable framework mounted immediately below the sealing ends to accommodate a phase plate in a conspicuous position. All phase plates shall be manufactured from mild steel sheet with vitreous enameled finish.

Don’t compromise to provide for fixing and bonding copper fittings as may be necessary to accommodate all apparatus affixed thereto and to secure the structures to their foundations.

Factors of Safety on Outdoor Structure for 132kV Power Cable

The factor of safety for each complete structure and foundation should not be less than 2.0, based upon the maximum working loadings specified and described below.

In calculations of the factor of safety the strength of compression members should be based on the crippling loads as International Standard formula.

The strength of both tension and compression members should be based on the elastic limit and the rate of unsupported length to their least radius of gyration should not be more than:

120 - for main members

200 - for braces

250 - for redundant members

350 - for members loaded in tension only

Maximum Simultaneous Working Loads on Outdoor Structure

The assumed maximum simultaneous working loads on the structures should be reckoned as follows:

Wind Loading of Structure

i) A wind pressure of 1427 N/m2 applied at right angles to the lines on the whole projected areas of phase conductors of 1686 n/m2 in the case of earth wires. A wind pressure of 1427 N/m2 shall also be applied to the projected area of each insulator set.

ii) A wind pressure of 4280 N/m2 on the whole projected area of any one face of the structure.

Vertical Loading on Structure

Vertical loadings should include dead weight of all conductors insulator and equipment and the self weight of the structure. 

All structures also should be capable of supporting a loading of 150 kg per phase to allow for imposed loads of men and tools during maintenance however this loading is not to be combined with other loadings in checking the overall factor of safety.

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Design of Outdoor Steel Structure for 132 kV Power Cable Installation

Fig-CAD drawing for steel structure

The compression members shall consist of rolled steel sections and the tension members of rolled steel sections or flats. The design shall be such as to keep the number of different parts as small as 

Pockets or depressions likely to hold water shall be avoided and if not avoidable shall be properly drained.

Steel structures should be fabricated from either mild steel BS4360 grade 43A or high tensile steel BS 4360 part 2 grade 50C. Notable that all material should be free from blisters, scale or other defects.

All members should be stamped or marked for erection purposes.

All members, fittings, bolts, washers, screwed rods, nuts etc., should be galvanized.

All parts shall be secured by means of bolts and nuts and screwed rods whose minimum diameter shall be 12.5 mm. All nuts and pins shall be locked in position by means of lock washers or other approved devices. Taper washers should be provided where necessary.

When in position, all bolts or screwed rods shall project through the corresponding nuts but by no more than 10 mm. Bolt heads rather than nuts shall be on the outer faces of members.

No bolts hole shall be more than 1.5 mm larger than the diameter of the bolt, but after galvanizing sufficient clearance shall be left for insertion of the bolts.

During erection care shall be taken to ensure that the structures are not strained or damaged in any way and that the treated surfaces are not injured. Rust streaks and foreign matter deposited on galvanized surfaces during transport and storage shall be removed.

Workmanship of Steel Structure

All members shall be cut to jig and all holes shall be drilled or punched to jig so that when the members are in position the holes will be truly opposite each other before being bolted up. Drifting or reaming of holes will not be allowed.

The drilling, punching, cutting and bending of all steelwork and the removal of sharp edges and burrs shall take place before galvanizing.

Approved steel gauges of the stud type shall be provided to enable checking of members as may be considered necessary by the qualified Engineer.

Built members shall when finished be true and free from al kinks, twists and open joints and the material shall not be defective or strained in any way.

In order to check the workmanship, not less than 1% of the members corresponding to each type of support shall if required be selected at random and assembled to form complete supports in the presence of the qualified Engineer at the manufacture’s works.

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Sun-shields on Structure for Power Cables

At places where power cables are brought above ground level e.g. sealing end structures, proper sun shields shall be provided and fitted. These shall comprise of perforated cable trays galvanized and fitted externally to each. Sealing end structure such as to shield the cable from sunlight and allow air flow over the cable.

Marking on Steel Structure Sections

All steel sections, fish-plates and gusset plates should be indelibly marked with an assembly code number or letter, or a combination of both, to facilitate quick recognition and correct assembly. If this identification is stamped on to the member, it’s may  applied before galvanizing.

Equipment Grounding for De-energized Construction and Maintenance

Importance of  Equipment Grounding for De-energized Construction and Maintenance:

Why grounding Is Require?

Electricity never give you the second chance. So, for safety 99.99% is not enough until 100%. Working with electrical equipment, switch off the power line is not enough for safe; it is very much essential to ensure de-energized the line by grounding.

How Does Grounding Work?

Sometime we even an expert also make mistake to grounding which electricity may get chance to takeaway our valuable life and property. So, no more literature; come and join the Hubbell Power Systems provided video clip to keep safe all of our colleagues:  Video Clip 

What Is Pipe Earthing And Plate Earthing?

Pipe Earthing is the best form of earthing. This is very cheaper than others in cost. In this method of earthing, a galvanized and perforated pipe of approved length and diameter is placed up right in a permanently wet soil.

The size of pipe depends upon the current following amount  to be supposed  and the type of soil condition, dry or wet. If the moisture of soil is very low ( or decreases in Summer ), in such case the resistance of earth is increases.

Plate Earthing an earthing plate of copper of generally dimensions 60cm×60cm×3mm or of galvanized iron of dimensions 60cm×60cm×6mm is buried into the ground with its face vertical to a depth of not less than 3 meter from ground level. High surface area allow the system to allow the high amount of current flow through the earth without any difficulty.

A normal masonry brick wall enclosure with a cast iron cover on top or an RCC pipe round the earth plate is provided to facilitate it .

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Specifications for Earth Electrodes

Generally we follow the following Earth Electrode specifications: The earthing electrode should not be placed near the building whose installation system is earthed more than 1.5 m away. The resistance of the earth wire should not be more than 1 ohm. The wire use for electrode and circuit should be made up of the same material. The electrodes should be placed in vertical position so that it can touch the layers of the earth. Better to select the size of the conductor should not be less than 2.6 sqmm or half of the wire used for electrical wiring. Bare copper wire is used for earthing and grounding for it's long lasting and good conductive properties. Green 6 THHN (Thermoplastic high heat neutral coating wire) and gauged copper wire of different sizes like 2,4,6,8 etc. are also used for earthing and grounding.

CABLE TRENCH EXCAVATION FOR POWER CABLE: UNDERGROUND PROJECT

Trenches Excavation  and Underground Cable Installation

The exact location of each trench should be selected and approved by the Engineer before cable trench excavation for the power cable of any underground cable project.

Trenches should be kept as straight as possible and each trench shall be excavated to an approved formation and dimensions and shall have vertical sides which would be timbered where necessary so as to avoid subsidence and damage.

It’s important to  excavate up to a depth of at least 100 mm below the base of cable laying. The bottom of each trench should be firm and of smooth contour. 

DRAWINGS DIAGRAMS AND CALCULATIONS FOR UNDERGROUND CABLE PROJECT

General Requirements And Importance Of Drawings-Diagrams For Underground Power Cable Project

The employer may engaged or contract with service-provider to execute an underground power cable project, service-provider actually carry out the whole works as per employer requirements. Here in this article we would like to focus on general requirements and importance of various drawings, designs and calculation sheet to execute an underground power cable project.

The term “drawing” should also included here diagrams, schedules, performance curves, and calculations etc. required for the comprehensive design of the works. The Service Provider should be responsible for the provision of all drawings required for the various stages of the Contract to execute the project.

All drawings, apart from workshop drawings, should be submitted to the nominated Engineer for his approval, in accordance with an approved program. 

The Service Provider should ensure that drawings are submitted for approval in prior enough time such that they may be approved within the specified period by the Engineer, prior to manufacture or construction commencing. 

Further adequate time must be allowed by the Service Provider to permit any comments for revised or modification made by the Engineer to be incorporated.

Any works performed prior to approval of drawings by the Engineer will be entirely at the Service Provider’s own risk including any delays that may result from modifications being found to be necessary by the Engineer.

The numbers of drawings required and the method of issue should be mentioned  in flow diagrams to  specification that keep free from any confusion.

The Service Provider should be fully responsible for obtaining any drawing or data of existing plant and installations that he requires in order to carry out the works, and should also be responsible for verifying that any drawings of existing plant and installations are accurate.

The Service Provider should provide suitable drafting and other staff on site that he requires investigating and producing any drawings that he requires of existing equipment and installations in order to carry out the works.

Where existing installations have been modified or extended the Service Provider may  provide complete new sets of drawings. In this respect the Service Provider should provide drawings detailing both the existing and new works and may not limit the scope of the drawings to the new works only.

What Should be Format of Drawings and Calculation Sheet ?

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Drawings are to be submitted for approval on paper prints, folded to A4 size with the project title-block and drawing numbers clearly visible. Details of the project title-block must be as per prior specified by employer.

All drawings are to be submitted on A series paper to ISO/5457. The maximum size of drawings should be A1 except for site survey and layout drawings which may be submitted as A0 size sheets, if necessary, to accommodate details on a scale of 1:100. Single line diagrams and schematic drawings should preferably be on a maximum sheet size of A2. All dimensional drawings should be the following scales and detailed.

• 1:1, 1:2, 1:5, 1:10 and factors of 10 thereof;
• Drawings symbols should be in accordance with IEC 117.
• All drawings are to be submitted in Auto Cad format in CDR Disk.
• Drawing titles should clearly identify the specific function of the drawings and where appropriate the name of the site(s) to which the drawing applies.

Cable Schematic Line Diagram

How Follow Drawing Numbering and Revisions?

The Service Provider should be responsible for adding the nominated Engineers drawing numbers to all drawings prior to submittal. Following award of the contract the Engineer and Service Provider will review the numbering system, familiarize with each other requirements, and agree on the numbering system to be applied.

Comprehensive cross-reference are to be included on drawings and the Service Provider should include the Engineer’s drawing number in the cross-references.

At each and every issue of a drawing the revision should be raised, and details given in revision boxes on the drawings. Comprehensive details of revisions are to be given and phrases such as “REVISED”, “UPDATED”, “MODIFIED” or similar are not acceptable.

Reference to any drawing in communications should include the Engineer’s drawing number.

Drawing Submittals and Approvals Procedure

The Service Provider should submit drawings for the plant and works for formal approval to the nominated Engineer. A program of drawing submittal should be agreed with the Service Provider following the contract award. 

Drawings issued in accordance with this program should take account of the time periods necessary for postage, and approved by the Engineer, to ensure that approved drawings are available prior to manufacture the materials for the project execute. For site construction works, “Construction Issues” drawings are to be available, on site, at least 21 days prior to the commencement of the works.Where appropriate the drawings should be accompanied by supporting calculations.

Following examination the Engineer should allocate a status on drawings. The subsequent action and distribution of drawings will depend on the status given by the Engineer as detailed below.

“Approved”, the details of the drawing have been checked by the Engineer and appear to comply with the requirements of the specification. Once approved the Service Provider should raise the revision to indicate Approved by the Engineer on Mark the drawing “Construction Issue” and distribute as per employer requirement that mentioned in contract.

“Approved Subject to Comment”. The drawing has been examined by the Engineer, and apart from the minor details can be considered Approved subject to the Service Provider making the amendments required by the Engineer. The Service Provider may issue the drawing as “Approved” as outlined above without resubmitting to the Engineer for formal approval, provided the corrections have been made as required. 

“Examined and Returned with Comments”. The drawing is considered to be revised by the Service Provider and immediately resubmitted to the Engineer for approval. 

“Examination not required”. The drawing not requiring approval by the Engineer has been examined by the Engineer. Examples of typical drawings of this nature are: equipment schedules and diagrams of connections. Drawings returned to the Service Provider of this status should be stamped “For information only” and “Construction Issue” and issued in the same manner as Approved drawings.

Approval of a drawing by the Engineer must in no way to relieve the Service Provider of his responsibilities under the Contract.

Service Provider may revise a drawing for any reason following approval by the Engineer, the revised drawing is to be resubmitted for re-approval by the Engineer, the original approval automatically being void.

The Service Provider must submit,  marked-up copies of the drawing issue programmed indicating the up to date status on drawing submittal and approval on a monthly basis. In addition the Service Provider should submit a schedule of the total number of drawing submitted, together with the total numbers of each of the above categories. An “S” curve is also to be submitted indicating the total number of planned approved drawing together with the actual numbers to date.

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As Built Recorded Drawing and Construction Amendment for Project

During construction of the Works on the site, the Service Provider should ensure that all departures, modifications and corrections to the approved drawings are recorded. All such changes to the drawings are to be marked in red to show on “as-built” stated and one set of “as-built” drawing are to be available on the site at all times.

If Service Provider wish to make modifications as per site requirement on the approved construction drawings which influence the operation of the Plant, he should obtain the approval of the Engineer’s representative prior to instituting the modifications.

Following examination of the “as-built” drawing the Engineer’s representative should return one copy to the Service Provider indicating approval of the construction modifications, or further modifications required to satisfy the requirements of the specifications.

Record Drawing for Cable Line Construction Project

On receipt of Approval of “as-built” drawings, the Service Provider  be responsible for the production of Record Drawings for the complete plant on each section of the Works.

The Service Provider should modify the revision to “As-Built” and “Record Drawing” for all drawings applicable to the section of the works and submit these for approval to the Engineer.

On receipt of the Engineer’s approval the Service Provider will provide sets of paper prints of each drawing as detailed on pre-specification of the contract. Any contract drawing included in the Operation and Maintenance manuals should also be revised in accordance with any “as-built” modifications and re-issued.

These sets of record drawings should be issued within 90 days of the Taking-over of the completed plant.