Showing posts from February, 2013


Considering the site condition for civil work of cable laying projectGeneralThis section of the works covers the design construction and maintenance of the civil works as required.
(i)Manholes for cable joints (ii)Manholes for oil pressure systems (iii)Road crossings and ducts (iv)Cable protective covers and route markers. (v)Foot Path
Foot pathsRates for supply and installation of equipment quoted in the appropriate Schedules shall be inclusive of all forms of foundations and ancillary equipment as fully completed covering excavation, ground preparation, installation testing and reinstatement and shall be deemed to have included all material guarding and all temporary and access works.
Contractor to Satisfy Himself as to All ConditionsThe Contractor will be held to have satisfied himself as to means of access to the Site of the Works, transport of labour, materials and plant to and from and over the works, construction problems, nature of ground on site and other relative contingencies


All instruments and meters shall be fitted with glasses of low reflectivity and shall not cause pointer deflection due to electro-static charging through friction.
All indicating instruments shall be of the flush mounted pattern with dust and moisture proof cases complying with BS 2011, Classification 00/50/04, and shall comply with BS 89:1977or IEC 51.
Unless otherwise specified, all indicating instruments shall have 95mm square cases to DIN standard or equivalent circular cases.
Instrument dials in general should be white with black markings and should preferably be reversible where double scale instruments are specified.
Scales shall be of such material that no peeling or discoloration will take place with age under humid tropical conditions.
The movements of all instruments shall be of the dead beat type.
Instruments shall be provided with a readily accessible zero adjustments.
The mounting height of the centre of all indicating instruments shall not exceed 2000mm.
AC ammeters for transfo…


Fuses are not to be used for protection of circuits below 1000V phase-to-phase, (Low Voltage).
All low voltage and dc circuit protection is to be provided by moulded case, or miniature circuit breakers (MCCB).
Link carriers and bases shall be of an approved manufacture and of such form and material so as to protect persons from shock and burns in normal service and maintenance. Links and fixed contacts shall be shielded to prevent inadvertent contact with live metal whilst the link is being inserted or withdrawn.
The labeling of carriers and bases shall comply with IEC 269Identification labels fixed to panels, boards and desks for MCBs and links shall describe their duty, voltage and rating.
MINIATURE CIRCUIT BREAKERS (MCB)All miniature circuit breakers (MCBs) shall be comply with IEC 157and be fitted with over-current releases of both the thermal and instantaneous type. All MCBs supplied on this contract shall be to short circuit category P2 of IEC 157.
Single, two or three pole breakers …


What Would be Normal Current Ratings?Current ratings in accordance with IEC 59 shall be adopted, unless otherwise agreed with the Engineer.
Every current carrying part of the equipment shall be capable of carrying its site rated current continuously under the Site conditions as specified, and in no case shall the permitted temperature rise be exceeded.
The current ratings specified are the continuous current ratings required at the Site, under the specified maximum temperature and solar gain conditions.
What Would be Short-Time Current Ratings?Electrical equipment shall be adequately supported and braced to withstand the forces associated with the maximum short-circuit currents specified or pertaining, whichever is the greater, and assuming that the inception of the short-circuit is at such a time that gives maximum peak currents, No provision for current decrement shall be made unless specifically permitted by the appropriate Standard, or elsewhere in this specification.
Equipment shall …


Spare Parts Availability Required for Plant and Equipment Maintenance, Emergency and Commissioning Purposes The Service-provider is responsible for providing adequate stocks of spare parts. In selecting plant for duty in Bangladesh serious consideration is to be given to the spares requirements. Manufactures are to certify that they shall ensure spare parts will be available for the lifetime of the equipment.
All parts supplied must be strictly interchangeable and suitable for use in place of the corresponding parts supplied with the plant. They shall comply with the Specification and are to be suitably marked and prepared for storage and provided in containers or packaging suitable for storage on tropical conditions. Where an item is subject to a limited shelf lift this shall be clearly indicated on the spares list, and the packaging etc shall be marked with the expiry date.
Maintenance and Essential Spares The Contract is to include for all spares required for the normal overhaul maint…


Safe and Secured Plant Access for Operation and Maintenance in Hazardous Area Provide Guard and Lock System The plant and equipment provided in accordance with this specification, shall either by its design and/or selection, or by additional sound absorbing enclosures supplied as part of this contract, meet the noise level requirements for both general work area limits, and neighborhood noise limits as specified herein.
The plant and equipment shall be deemed to meet the requirements of this specification if the noise levels measured, or calculated from measurements after background and other corrections have been applied, and after any appropriate tolerances have been allowed in accordance with the given standards do not exceed the noise limits specified.
The nomenclature, measurement and calculation procedures and the procedure for acceptance shall be in accordance with the Oil Companies Materials Association (OCMA) Noise Procedure Specification, NWGI. Measurements shall be made of the…


Plant Materials and Equipment Testing Procedure Where no specific test is specified then the various items of plant, materials and equipment shall be tested in accordance with the appropriate IEC standard. Where no appropriate standard is available, tests shall be carried out in accordance with the maker’s standard practice, subject to the prior approval of the Engineer. In all cases, works tests shall include electrical mechanical and hydraulic tests in addition to any tests called for by the Engineer to ensure that the plant being supplied fulfils the requirements of the Specification.
If considered necessary by the Engineer any multi-part assemblies shall be fully erected in the Works prior to packing and dispatch to Site.
All tests to be performed during manufacture, fabrication and inspection shall be agreed with the Engineer prior to commencement of the work. The inspection schedule included in the Schedules of Miscellany shall be used for this purpose. The Service-provider shall p…

Planning of Works and Contractor’s Responsibility

Contractor’s Responsibility on Planning of Works to Execute A Underground Cable Project
Within 30 days after acceptance of the Tender, the Contractor shall prepare, in an agreed form, a detailed Manufacture, Delivery and Erection Program Chart for the complete Contract Works, and shall submit the chart to the Employer for approval.
The Manufacture, Delivery and Erection Program Chart shall indicate for each major item of the Contract the various phases of work from the commencement of the Contract to its completion, e.g., design, ordering of materials, manufacture, delivery, installation and commissioning. The program shall include a fully comprehensive drawings production program which shall demonstrate the Contractors intended issue dates for approval.
These presentations shall be in bar chart and precedence critical path analysis format.
The program shall indicate percentage completion points of the various phases which can form the basis of progress reporting.
A cash-flow forecast of…


Contractors Generally Overall Responsible on Site During Work in Progress at Sites
Unless stated specifically to the contrary in the schedule of departures submitted with the Tender with full supporting explanations, the Contractor will be deemed to have concurred as a practical manufacturer with the design and layout of the Works as being sufficient to ensure reliability and safety in operation, freedom from undue stresses and satisfactory performance in all other essentials as a working plant.
The Contractor is to include the whole of the Works that are described in or implied by the Contract document, to provide complete, fully operable, safe and efficient installations, in accordance with internationally accepted practice. All matters omitted from the Contract document which may be inferred to be necessary for the efficiency, stability and completion of the Works shall be deemed to be included in the Contract Sum.
Works shown in the drawing and not mentioned or described in the speci…


Restricted Working Period In Bangladeshi Electrical ProjectDue to monsoon rain between July and September, work may slowdown. Due to traffic, work along /across road has to carefully plan. 

The Contractor shall obtain reliable Information concerning the conditions appertaining to the working areas covered by this Contract and shall plan his work in accordance with local conditions.

SYSTEM ELECTRICAL PARAMETERS IN BANGLADESH230 kV Transmission System in BangladeshNormal Service Voltage                                        :           230     kV Rated Voltage                                                         :           245     kV Insulation Level - Lightning Impulse Withstand                               :           1050  kV 50Hz dry 1 minute Withstand                             :           460     kV Number of Phase                                                   :           3 Frequency                                                                :           50       Hz Switchge…


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