1. Scope – This Article is about Electrical Engineering and Design and Skills required to become Electrical Design Engineer. Here we will discuss about Electrical Design Deliverables of Electrical Project in Building Plant and Petrochemical Facilities.
Codes, Standards, and Specifications
- The electrical engineering and design shall be described in the contract scope. The responsibilities of the ENGINEERING CONTRACTOR for each plant area or equipment package will be detailed and may include any one or more of the following:
- Detailed engineering services: Development of power system studies; electrical/instrumentation interface definition and management; electrical load chart development and management; high voltage, low voltage, and instrumentation single line diagram development and management; equipment rating calculations; electrical protection studies.
- Procurement activities: enquiry and purchase requisitions, technical bid reviews and tabulations, procurement and supplier document management/control.
- Detailed design and drafting of the plant electrical power distribution, lighting and small power, and earthing systems, including interfaces with all other disciplines. The other disciplines are instrument and controls (I&C), machinery, civil, piping, and structural engineering. This shall include the production of design drawings, diagrams, data sheets, charts, design calculations, and bills of materials (BOMs).
- The review of supplier documentation, the collation of equipment operating manuals and production data dossiers, and the incorporation of data from these into the detailed design.
- Construction and/or commissioning support (response to site queries, etc.).
- The ENGINEERING CONTRACTOR shall refer to the project-specific documents, such as the specific scope of work and the overall single line diagram, to identify the EC’s full electrical contract scope.
2. Codes, Standards, and Specifications
2.1 General
The design codes, industry and Company engineering standards, design guides, specifications, and QC plans are noted in the following information.
2.2 Design Codes
The ENGINEERING CONTRACTOR shall design all electrical work in accordance with ENGINEERING CONTRACTOR (NFPA #20) as stated in the contract scope. The ENGINEERING CONTRACTOR shall advise Company if any local or country codes take precedence over these international codes before proceeding with the design.
2.3 Standards
Industry standards issued by the ANSI/NEMA shall be followed as appropriate to meet the design codes and/or Company requirements. The Company engineering standards and design guides relating to electrical design will be listed in the contract scope appendix.
2.4 Specifications
The Company specifications relating to electrical design will be listed in the contract scope appendix for reference and use by the EC.
2.5 Quality Control (QC) Plans
QC Plans for various pieces of electrical equipment will be listed in the contract scope appendix. These QC Plans shall be included in any procurement packages for electrical equipment as appropriate.
3. Company Deliverables to the Engineering Contractor
3.1 General
- This section provides a description of the electrical drawings and documentation that will be provided by Companyas a basis for the EC’s scope of services and scope of supply. In addition, the ENGINEERING CONTRACTOR should make reference to the drawings provided as part of the contract by other disciplines.
- The following documents will be issued with the ENGINEERING CONTRACTOR enquiry package:
- Scope of services by the EC
- Overall simplified single line diagram
- High Voltage (HV) and Low Voltage (LV) single line diagrams (as applicable)
- Electrical load summaries
- Typical LV switchgear schematic diagrams
- Company equipment specifications and data sheets
- Additional deliverables may be provided by Companyto further define the interfaces. Refer to the contract scope for details.
- Typical Company specifications are available for information if requested by the EC. Associated blank data sheets are also available.
3.2 High Voltage (HV) and Low Voltage (LV) Single Line Diagrams
These drawings show the main power arrangement proposed and the scope split between the ENGINEERING CONTRACTOR and Air Products. The drawings identify the fundamental requirements for the power system. It is the responsibility of the ENGINEERING CONTRACTOR to enhance and finalize these drawings to fully define the detailed design. The single line diagrams shall identify the switching, interconnection, inter-tripping, interlocking, protection, alarms, and metering requirements.
3.3 Electrical Load Summary
This document will provide a preliminary list of the plant loads to be connected to the power supply. The ENGINEERING CONTRACTOR shall further develop this list in accordance with the detailed design information from other design disciplines and equipment suppliers.
3.4 Typical LV Switchgear Schematic Diagrams
Typical LV Switchgear Schematic Diagrams will be supplied by Companyto give the ENGINEERING CONTRACTOR an indication of the control and interface requirements. They also enable the ENGINEERING CONTRACTOR to develop the LV Interconnection diagrams for the project before receiving the switchgear supplier’s final drawings.
3.5 Electrical/Control and Instrumentation Chart
Company will prepare and issue a document defining the preliminary interface requirements, (digital and analog signals) between equipment specified by the Electrical discipline and that specified by the I&C (instrument and controls) discipline. The ENGINEERING CONTRACTOR shall update and reissue this document periodically to incorporate any changes for final equipment changes, P&ID changes, and general design development.
3.6 Instrumentation/Control Supplies Single Line Diagram
Company will produce a diagram to indicate the required Instrument power/control supplies and loads from the uninterruptible power supply (UPS) system. The ENGINEERING CONTRACTOR is responsible for enhancing and finalizing these drawings to fully define the detailed design.
Company will produce a diagram to indicate the required AC and DC power/control supplies and loads from the constant voltage transformer (CVT) and batteries and charger system. The ENGINEERING CONTRACTOR is responsible for enhancing and finalizing these drawings to fully define the detailed design.
3.7 Standard Installation Design Details
Company will provide standard installation details for information. These details will be issued to assist the ENGINEERING CONTRACTOR in completion of the installation design. If specific site or equipment installation details are required, they shall be produced by the ENGINEERING CONTRACTOR with support from Companyas necessary.
4. Deliverables from the Engineering Contractor
4.1 General
- This section provides a description of the basic scope/content of the electrical drawings and documentation that the ENGINEERING CONTRACTOR is required to provide as part of the electrical engineering and design scope.
- All project drawings shall be prepared using PDS Raceway/Micro Station or Auto Cad design tools with the deliverables created in dgn or dwg format. The extent of the electrical modeling shall be defined in the contract scope and any documents listed in the appendix.
- Text-type deliverables (e.g., data sheets, reports) shall be prepared using Microsoft Word or Microsoft Excel.
- The drawing list below is in addition to those provided in preliminary format by Company to be developed by the EC. It does not necessarily include all drawings within the ENGINEERING CONTRACTOR scope of supply. An electronic reference copy shall be transmitted to Company at each issue of all drawings.
4.2 Design Deliverables
- The design deliverable scope may include any or all of the following as applicable to the specific job:
- Cable charts and cable drumming charts.
- Earthing/Grounding and lightning protection layouts.
- Lighting and small power layouts and calculations.
- Electrical routing layouts.
- Power and control cable layouts.
- Switchgear and transformer area and control room layouts.
- High voltage interconnection diagrams.
- Low voltage interconnection diagrams.
- Fire, telephone, and closed circuit television systems.
- Electrical heat tracing design.
- Electrical single line diagrams.
- Electrical control schematic diagrams.
- Power panel/Distribution board charts.
- Hazardous area classification drawing(s) (when relevant).
- Standard electrical drawing symbols and installation details.
- The ENGINEERING CONTRACTOR shall coordinate the electrical design with all other applicable disciplines to ensure that the design does not conflict with required access ways or any specific clearance distances from equipment.
4.3 Cable Charts and Cable Drumming Charts
- The ENGINEERING CONTRACTOR shall produce detailed cable charts for all power and control cabling within the EC scope. These charts shall at a minimum include the following data:
- Cable number per Companynumbering system
- Cable type
- Voltage
- Size (cross-sectional area and number of cores)
- Length
- Cable gland size
- From (point of origin)/To (point of destination)
- Cable drum reference
- The chart for HV cables should also include the type, size, and supplier’s reference of the suitable high voltage stress-relieving termination kit/fittings as required. The chart shall also incorporate the suitable clearance size of support conduits between main cable route/racks and the equipment (refer to Air Products’ cable installation details).
- All cables shall be in accordance with applicable Company standards and specifications as defined in the contract scope and appendix.
- The ENGINEERING CONTRACTOR shall develop a material take-off including gland/termination materials as defined in the contract scope.
- The ENGINEERING CONTRACTOR shall develop a cable drumming chart when required by the contract scope. The drumming chart shall be a listing of the various types, sizes, and lengths of electrical cables that are to be supplied. It shall designate the length of cable required on each drum or reel of the cable.
- Cable charts are also known as cable schedules. Cable drumming charts are also known as cable drumming schedules.
4.4 Earthing/Grounding and Lightning Protection Layouts
The ENGINEERING CONTRACTOR shall produce detailed design layout drawings that indicate at a minimum the following: all above-ground and below-ground conductor/cable routes, conductor sizes, air terminals, termination points and details references. These shall all be in accordance with Company installation details. The ENGINEERING CONTRACTOR shall also produce a complete and accurate bill of materials for all grounding system equipment.
4.5 Lighting and Small Power Layouts and Calculations
The detailed design scope of the lighting systems shall include the lighting calculations and layout drawings indicating lighting fitting types and positions. The detailed design shall also include lighting circuits, distribution board charts, installation detail references, and cable routing for those areas of the plant within the EC’s scope. The ENGINEERING CONTRACTOR shall also produce a complete and accurate bill of materials for all lighting and small power equipment.
4.6 Electrical Routing Layouts
The ENGINEERING CONTRACTOR shall produce the cable support systems detailed design. This may comprise a combination of trenching, ladder rack/tray-work, and/or conduit systems. Refer to the contract scope for details of the method to be used. The ENGINEERING CONTRACTOR shall also produce a complete and accurate bill of materials for all cable support system materials.
4.7 Power and Control Cable Layouts
The ENGINEERING CONTRACTOR shall produce power and control cable routing and termination point detailed design. This detailed design scope may include cables associated with both Air Products-supplied and EC-supplied equipment as defined in the contract scope.
4.8 Switchgear and Transformer Area and Control Room Layouts
The ENGINEERING CONTRACTOR shall develop and finalize equipment arrangements/layouts and civil requirements for these areas. This may include working with civil/structural department.
4.9 High Voltage (HV) Interconnection Diagrams
The ENGINEERING CONTRACTOR shall use the HV switchgear supplier’s final schematic drawings to develop HV interconnection diagrams. The interconnection diagrams shall indicate termination details at both ends of the control cables associated with the electrical equipment.
4.10 Low Voltage (LV) Interconnection Diagrams
The ENGINEERING CONTRACTOR shall use the LV switchgear supplier’s final schematic drawings to develop LV interconnection diagrams. The interconnection diagrams shall indicate termination details at both ends of control cables associated with the electrical equipment.
4.11 Fire, Telephone, and Closed Circuit Television (CCTV) Systems Layouts
- The detailed design scope for the fire alarm system shall include the equipment layout drawings showing equipment types and positions, cable routing, fire alarm zoning, installation detail references, interfacing between the plant and buildings’ fire systems, and the specification and procurement of suitable equipment when required by the contract scope.
- The detailed design scope for the telephone systems shall include the equipment layout drawings showing equipment types and positions, cable routing, installation detail references, interfacing between field and building systems, and between the plant and local utility as required.
- The detailed design scope for the closed circuit television system shall include the equipment layout drawings showing equipment types and positions, cable routing, installation detail references, interfacing between the plant and buildings fire systems, and the specification and procurement of suitable equipment as required.
- The ENGINEERING CONTRACTOR shall also produce a complete and accurate bill of materials for all materials.
4.12 Electrical Heat Tracing Design
The detailed design scope of the electrical heat tracing shall include the cable/tape selection and design calculations and equipment charts. The detailed design shall also include layout drawings, distribution board charts, bills of materials, installation detail references, and cable routing.
4.13 Electrical Single Line Diagrams
The ENGINEERING CONTRACTOR shall produce electrical single line diagrams showing the incoming feeds, the substation, and the power distribution systems. The diagrams shall show the fundamental requirements of the main power arrangement and the boundaries of responsibility. The diagrams shall identify the switching, interconnection, intertripping, interlocking, protection, alarms, and metering requirements of the electrical equipment.
4.14 Electrical Control Schematic Diagrams
The ENGINEERING CONTRACTOR shall produce electrical control schematic diagrams showing how all of the electrical equipment is controlled and how it interacts with other devices. The diagrams shall be prepared in schematic format.
4.15 Power Panel/Distribution Board Chart
The ENGINEERING CONTRACTOR shall produce power panel/distribution board charts for all of the low voltage electrical panels. The chart for each panel shall show the panel’s name and number and the name and number of each circuit connected to the panel. Circuit breaker phase configuration and ampere rating for each circuit shall be provided. A local schematic for the power feed to each panel shall be provided.
4.16 Hazardous Area Classification Drawing(s) (when relevant)
The ENGINEERING CONTRACTOR shall produce a hazardous area classification drawing(s) when relevant to the type of plant being designed. The drawing shall identify the various areas of the plant and into which electrical classification(s) they belong. The electrical classifications shall be in conformance with the electrical code being used for the design.
4.17 Standard Electrical Drawing Symbols and Installation Details
The ENGINEERING CONTRACTOR shall produce a drawing(s) showing all of the symbols used on the various electrical drawings. The meaning of each symbol shall be fully identified. The ENGINEERING CONTRACTOR shall produce a drawing(s) showing the proper installation details of electrical equipment and items that are used repeatedly in the plant.
4.18 Engineering Deliverables
- The engineering deliverables scope may include none, some, or all of the following. In addition, it is not necessarily limited to the following. Specifics will be given in the contract scope.
- Equipment data sheets
- Technical bid tabulations
- System study reports
- Electrical and instrumentation interface chart
- Load summary and equipment sizing calculations
- Electrical protection study and relay setting chart
- The engineering activities shall also include all work necessary to support the design activities within the ENGINEERING CONTRACTOR scope to ensure that the design package produced shall sufficiently detail the installation/construction scope.
- Supporting information including calculations shall be performed and recorded. The extent of the documentation shall be listed in the EC’s document register.
- The ENGINEERING CONTRACTOR shall refer to the contract scope for specific additional deliverables or deliverables deleted from these requirements.
4.19 Equipment Data Sheets
Copies of equipment data sheets and the status of any purchase orders for electrical equipment for which the ENGINEERING CONTRACTOR is responsible for the detailed design and procurement shall be issued to Air Products.
4.20 Bid Tabs
The ENGINEERING CONTRACTOR shall be responsible for the technical and commercial review of bids for the EC- procured equipment. These bid evaluations indicating technical compliance and/or deviation lists and supplier experience lists shall be submitted to Company for approval.
4.21 Supplier Equipment Data
- At a minimum, this documentation shall consist of copies of supplier equipment data sheets, schedule, Quality Analysis (QA) documents, and drawing packages including Operation and Maintenance Manuals issued to Companyfor review before final sign-off by the EC. Copies of all as-built documentation for the equipment information are also required.
- The extent of Air Products’ review/approval of supplier equipment data will be defined in the contract scope.
4.22 Electrical System Study Reports
- The contract scope will define the scope of electrical system studies/calculations required for the project and which calculation methods should be used to generate these. These studies shall be prepared using the SKM Power Tools for Windows software suite.
- The systems studies may include any of the following:
- Motor starting studies
- Fault level studies
- Load flow analysis (including definition of tap changer positions)
- Harmonic analysis
- The ENGINEERING CONTRACTOR shall produce at least two issues of these study reports. The first is to support the procurement cycle (to demonstrate the suitability of the equipment specified before order placement). The second shall use as-tested data for all high voltage equipment.
- In addition to the submittal of these reports, the ENGINEERING CONTRACTOR shall also provide electronic copies of the software system models used in the production of the studies.
4.23 Electrical and Instrument (E&I) Interface Chart
- The E&I interface chart shall be developed by the ENGINEERING CONTRACTOR from the preliminary version provided by Air Products. This chart shall be used as the basis for both the procurement of the E&I interface panels and for the definition of the cabling interfaces between the electrical and instrument work.
- This chart shall be regularly reviewed and revised by the ENGINEERING CONTRACTOR as necessary to keep it up-to- date with the current versions of the load lists and P&IDs.
4.24 Load Summary and Equipment Sizing Calculations
- The ENGINEERING CONTRACTOR shall develop the preliminary load list supplied by Companyusing the detailed design information from other design disciplines and equipment suppliers.
- This load list shall indicate the normal operational status of each electricity consumer (continuous, intermittent, standby) to provide a normal and peak equipment loading for each switchboard.
- The normal operating load shall be defined as 100% of the continuous load + 30% of the intermittent load + 10% of the standby loads. The ENGINEERING CONTRACTOR shall then use these results and any project-specific equipment sizing margins to confirm the equipment ratings defined by Companyon the single line diagrams. If any inconsistencies are found, they shall be highlighted to Companyfor review and approval of any required changes.
4.25 Electrical Protection Study and Relay Setting Charts
- The ENGINEERING CONTRACTOR shall develop the electrical protection study from the single line diagrams, system study reports, and appropriate supplier documents. This study shall include the following elements.
- System protection description (the types of protection used on each type of circuit).
- Required protection grading margin (calculated with reference to the type of protection function and relay/breaker types used).
- Time/current curves to depict the selected relay settings graphically. These shall include details of motor run-up times, system fault levels, etc.
- Relay setting charts, including settings for all adjustable protection devices used on the project.
- Narrative to describe the protection settings chosen (e.g., whether the required grading margin is achievable).
- Actions/holds list for other parties (power supply authorities, etc.).
- This preliminary study shall be developed early enough in the project schedule to demonstrate that the protective equipment being procured is suitable for the application. The final version shall use the as-tested electrical system study data and shall include details of any protection devices supplied by others that may have an operating effect on the electrical system.
5 Approval/Review of Deliverables Produced by the ENGINEERING CONTRACTOR During the Design Phase
5.1 Division of Work Responsibility Matrix
| Description | Issued for Action |
| ENGINEERING CONTRACTOR Document register (issued monthly) | I |
| Interfaces between Company and the EC | I |
| Electrical specifications and data sheets variations to specifications | I |
| Data sheets | A |
| Electrical load summaries | R |
| Electrical cable volt drop calculations | A |
| Technical bid tabulations | A |
| Electrical system study reports | A |
| Electrical protection study and relay setting charts | A |
| Electrical Cable Charts, to include cable fitting/termination data as required and a cable BOM | R |
| Cable drumming charts | I |
| Lighting calculations and layouts | R |
| Electrical/control instrumentation interface | R |
| Hazardous area classification drawings | A |
| Electrical earthing/grounding and lighting protection (layout drawings and equipment BOM) | A |
| Power and control cable layouts | R |
| Electrical routing layouts | R |
| Single line diagrams | A |
| HV schematics and wiring diagrams | A |
| LV schematics and wiring diagrams | A |
| Fire alarm system drawings | R |
| Closed circuit television system drawings | R |
| Telephone/communications system drawings | R |
| Electrical heat tracing layouts | R |
| Electrical heat tracing schedule and calculations | R |
| Power panel/Distribution board charts | R |
| Material take-offs/bills of material | I |
| Field check-out procedures | I |
| Switchgear and transformer layout | A |
| Control room layout | A |
| Supplier equipment drawings | I |
A=Approval I=For Information R=For Review
5.2 All electrical equipment suppliers shall be approved by Company. If the ENGINEERING CONTRACTOR wants to use suppliers who were not previously approved by Owner Company, the ENGINEERING CONTRACTOR must obtain information from the suppliers to allow Company to judge their acceptability. At a minimum, details of the suppliers’ manufacturing experience and their quality control system must be provided to Company for evaluation.
5.3 The ENGINEERING CONTRACTOR shall perform electrical equipment source inspections for the equipment purchased by the EC. The inspections shall be in accordance with the appropriate QC Plans listed in the contract scope appendix.
Electrical Work Technical Specification Petrochemical Plants