Electrical Bill Of Quantity (BOQ) - Part Two


In our first Article about Bill of Quantity (BOQ) on the following link " BILL OF QUANTITIES ", we explained the following points:


  • The Purpose of a Bill of Quantities,
  • BOQ Creation Procedures,
  • BOQ Types,
  • Difference between BOQ & BOM (Bill Of Materials).


Today, we will explain how to write the BOQ for Electrical items.




Bill of Quantity (BOQ) Definition:

It is a document used in bidding. Which include details the terms and conditions of the construction contract and itemizes all work to enable a contractor to price the work for which he is bidding.


to understand the Bill of Quantity (BOQ) for Electrical items, we will explain the following points:


  1. Basic Principles of BOQ,
  2. Electrical Items Description,
  3. General Notes.




  
1- Basic Principles of BOQ




Bill of quantities shall be made "Preamble and count" by a design engineer  " or draftsman"  and in coordination with the owner in his vision to implement the project in terms of:


  • It Must be clarified whether the price of the items includes the price of supplying the item only or the price of supplying and installing the items.
  • Items and their requirements must be clearly described so that the contractors can pricing.
  • Items are recognized in the BOQ that must be divided into the fields (item number, description, unit, number / meter, unit price, total price) In order to regulate the bill of quantities and to be able to collect the cost and compare offers from contractors.






  • Items must include all details not clarified in the drawings or other documents of the project. The document containing the item description should be mentioned in case it is not fully specified in the bill of quantities




  
2- Electrical Items Description




  


ITEM #1:  Transformer

Describe: 



























  • Transformer type (Dry / Oil .. )
  • Winding type AL or CU " In distribution and small power transformers, aluminium–aluminium windings have been successful. For large power transformers, a copper–copper design is more common.
  • Transformer rating KVA
  • Voltage Rating  11/0.4 KV. 
  • Tapping if found (±2 x 2.5%)
  • Vector group Dyn11
  • IP00 (unenclosed)
  • naturally air cooled (AN)

Important Notes:


  • Everything mentioned in the description affects the price of the item and therefore it is preferred to be described.
  • You can mention the drawing code which includes any extra description for the item. As well as any other documents relating to the item.

Quantity: 

Quantity "number" counted from the project drawing.





  
ITEM# 2:  Generator 

Describe: 



  • Fuel type: A portable generator is powered by gas, diesel, .. fuel.
  • Working type: Standby, Prime or Continuous Power Generators.
  • Soundproof Enclosures Additional requirements in case of need, It is usually used in the case of generators installed inside the building
  • Rating:  KVA, Power factor, voltage, frequency, number of phases.
  • Control panel for generator. include Generators synchronization panel
  • All usage requirements: fuel, tank and ventilation pipes.. 
  • heaters needed to prevent accumulation of moisture and dampness Helps to maintain the stator windings above the dew points

Important Notes:


  • The heater is wired to be "on" at all times when the generator set is not operating It can help to lengthen the life of the alternator in adverse conditions commonly used
  • "Moving the (100KVA) generator from its place to the new in the first floor building including all required installation and components such as cables and other things" , Here the item is mentioned only in order to move the generator from one place to another. Even transportation needs to be costed and must have a separate item. and quantity " Lump Sum LS"

Quantity:  


Quantity "number" counted from the project drawing. or " Lump Sum LS" for 1 generator.





  
ITEM# 3:  Electrical panels

Describe: 





  • Each electrical panel is listed as a separate item because of the price difference from panel to another according to their components.
  • The main panels were separated from the distribution panels due to the different specifications of each
  • The components of the panels must be determined whether there is a meter or a degree of protection or ...
  • The components of each panel can be described in the BOQ as shown in the image. It would be preferable to described the components in one document in the project " at drawing". To reduce human errors in Write the description and to prevent data conflicts


Quantity: 

Quantity "number" counted from the project drawing.





  
ITEM# 4:  Cables and bus-bar

Describe: 



  • Type of cable: single core, multi core
  • Type of insulation: PVC or XLPE optional SWA, LSZH.
  • Voltage (low voltage or medium voltage)
  • Determine the method of installing the cable if it is on cable tray or inside pipes or underground
  • If cable tray are used, it is necessary to determine whether the item price includes the price of cable tray or has a separate item



Quantity:


  • Quantity "by Meter" Calculated from drawings.
  • Autodesk  free APP can help by calculate polyline Link here 





  
ITEM# 5:  Lighting system

Describe: 



  • The cross sectional area of wire.
  • Clarify if the item contains the connection of the lighting unit to the switch of the light. 
  • The number of outlets is calculated by the sum of lighting systems used " lighting units, lighting switches"
  • In some other cases, the total number of circuits used in the project is calculated instead of the number of outlets







  • Type F1, Must be described at project drawings " legend ", The description can also be written fully at the BOQ

Quantity:  


  • Units of each type are counted from project drawings.
  • Autodesk  free APP can help 





  
ITEM# 6:  Power system

Describe: 



  • Sockets & disconnect switch outlets 
  • The cross sectional area of wire.
  • The number of outlets is calculated by the sum of all items systems quantities, which have the same cross section area.
  • In some other cases, the total number of circuits used in the project is calculated instead of the number of outlets.






Quantity:  



  • Units of each type are counted from project drawings.
  • Autodesk  free APP can help 




  
ITEM# 7:  Earthing system 

Describe: 





It is common to include the earthing system item in Lump sum.








  
3- General Notes




  • With the same principles, light current systems are added.
  • The cost of the supply can be separated from the cost of the installation if an owner request that.
  • BOQ can be prepared only for installation. This point is determined by the owner





  • The approved suppliers list must be attached with BOQ to estimate the price level of the units required according to the cost proposed by the owner.
  • Also, no item is specified in the drawings, BOQ or the list of suppliers with one supplier. Provide more than one supplier and write a statement "or other approved equal ". So as not to fall into the suspicion of bias to one supplier. Except in case of agreement with the owner.
  • The BOQ varies from one engineer to another, through its experience with the projects that have been implemented and what we have presented previously only for initial clarification


Reference:

- Open source BOQ




About the Author:

Eng. Eman Mohamed 
https://www.linkedin.com/in/eman-mohamed-0459774a/


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