This article includes key activities for designing electrical works for any type of building such as residential, commercial, malls, educational, hospitality industry, etc.
There are 14 unique characteristics for ensuring the robustness of electrical works design, as summarised below.
1Optimum usage of energy-saving BOQ materials and systems for electricals such as Transformers, solar power systems, low fuel consumption gensets, etc .
2. Design and choose BOQ that conforms to International and local quality standards.
3. Design systems that enable equipment installation and commissioning with optimum capacity.
4 Layout schemes that are designed so that the power supply distribution system, cables, and wires specifications are optimum and are concealed.
5. Design electrical systems that are eco-friendly and enable sustainable energy.
6. Design electrical system arrangements that are easy to maintain.
7. Developing designs that are flexible to meet challenges related to potential changes in technology and energy savings
8. Designs that are scalable and expandable
9. Configuring the design of BOQ, installation and commissioning so that the integrated solution meets statutory requirements
10. Choose and approve brands that enable minimum downtime.
11. Designing solution that enable optimum cost of ownership as also running costs.
12. Proposing designs of electrical fixtures, lamps, and lights to meet the lighting system requirements of customers for all external, internal and landscape areas,while ensuring minimum energy costs.
13. Delivering designs and line diagrams that follow international standards for symbols of electrical items, wire, and parts numbering schemes and are easy to understand.
14. Ensuring Integrated BMS-building management solutions.
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Three (3) essential Inputs that contribute to good design practices for electrical works
i) material specifications related
ii) installation and commissioning related
iii) Building quality with the use of appropriate design software
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i) Material specifications related -
External electrical-/High side works | Key specifications of Building materials to be specified |
Electrical substation materials -transformers, circuit breakers, poles, earthing, disconnect switches, cables, wires etc | Capacity, make/ brand, voltage class, statutory safety standards, sizes, high voltage withstand, insulation properties |
VCB-Vacuum circuit breakers and their components | Capacity, make/ brand, type, material with high density, high electrical conductivity, high thermal conductivity, high arc resistance capability, low resistance, safety standards compliances. |
ACB-Air circuit breakers and their components | Capacity, Type of ACB, Make, brand, size, Rated voltage protection, rated current protection, overload relay tripping -current settings, rated short-circuit breaking capacity, statutory or & safety compliances |
Transformers with ferromagnetic steel | Capacity. Core Type, Make, brand, size, High permeability, low hysteresis loss, statutory or & safety compliances |
Panels (circuit breakers, bus bars, PLC, relays and contractors, Steel boxes bus bars, buttons, indicators | Capacity. Type, Make, brand, size of the complete panel and its components, conductivity, earthing, statutory or & safety compliances |
Electrical distribution boards With switches, bus bars, circuit breakers, fuse links | Safety characteristics, overcurrent protection, space for wires, fixtures, cables, corrosion resistance, statutory or & safety compliances |
High tension Cables(Copper or aluminum conductors) | Make, brand, Size, no of cores, insulation, resistance to abrasion and wear and tear, non-corrosive, low resistance, statutory or & safety compliances |
Backup equipment like Diesel Generating sets, inverters, UPS, Solar lighting panels | Make, brand, KW ratings, fuel consumption (for gensets), maintenance, statutory or & safety compliances |
High-speed diesel/fuel storage-related tanks, pipes, cooling towers, metering units, | Make, brand, capacity, firefighting capability, statutory or & safety compliances |
and so on | |
ii)Inside electrical/low-side designs | Key specifications of Building materials to be specified |
Conduits, low-tension cables/wires, and accessories | Make, brand, size, ratings, colours, safety compliances statutory requirements |
Electrical fixtures and lamps, switches, and sockets | Type, Make, brand, size, IP ratings, styles, finish, safety compliances, lamps-types, light intensity, light colour etc statutory requirements |
CCTV, video phones, public address systems, telephones, etc. MATV (Master Antenna Television system), wi-fi Equipment | Type, Make, brand, size, ratings, styles, finish, and statutory requirements |
and so on |
ii)Installation and commissioning related
Installing designs and drawings in electrical works, good practices for construction, installation, and commissioning of the following and applicable quality standards.A few examples are under
a) High-side electrical works related
i) HT cables and earthing
ii) Rising mains, panels and metering boxes
iii) DG sets and solar panels
iv) Exhaust systems, cooling towers etc
v) All other BOQ items in
b) Low-side electrical works related
i)Laying of conduits, wires, cables, and accessories
ii)Installing & commissioning electrical fixtures and lamps
iii)Installing & commissioning access control systems like CCTV, Videophones
iv)Installing & commissioning metering units and public address system, telephones etc
v)Installation, testing, and commissioning of a completed low-side electrical package
And so on
c) Building quality in the MEP-Electrical design process using designing software
• Computing total power loads, assessing the Capacity of each type of equipment
• Incorporating installation, testing, and commissioning aspects
• Including detailed 3D models depicting electrical components like entire electrical
layouts with BOQ depicted, ductwork, electrical fixtures, lighting, lamps, switches,
sockets, etc.
• Circuit designs and reuse
• Identify any inter or intra-discipline clashes
• Develop electrical works related to shop drawings using international conventions for wires and component-numbering tags
• Designs supporting all applicable electrical standards
Software like AutoCAD Electrical, Smart Draw, Autodesk, Ansys, or similar ones having 3D MEP BIM modeling features can be considered for developing electrical works related to designs.
Eight stages for developing the design of Electricals
Design activities vary considerably from company to company but generally, there are 8 stages to designing the MEP-Electrical works for buildings as below. Whatever designing processes and software are used, designing must result in developing Robust designs by accomplishing the following:
• Build designs that are comprehensive, accurate
• Contributes to building quality in construction by incorporating national and
international quality standards in BOQ/material specifications and construction
processes
• Integrates statutory and safety requirements (if applicable) in the designs and drawings
• Optimise project costs
• Enables efficient delivery of designs & drawings
• Incorporates maker-checker step in each design stage through the implementation of
segregation of duties concept
8 stages are
Stage 1 - Develop a preliminary design brief and drawings
Stage 2 - Develop detailed drawings and schemes.
Stage 3 - Develop schematic drawings for statutory approvals
Stage 4 - Develop a Tender with BOQ and specifications
Stage 5 - Develop construction drawings duly coordinated (GFC)
Stage 6 - Carry out and validation of design calculations
Stage 7 - Making Cost estimates- including values in Rs and Cost/Square foot of saleable
area or built up as appropriate.
Stage 8 - Develop as-built design calculations and as-built drawings
This may require using software such as AutoCAD Electrical, Smart Draw, Autodesk, Ansys, and other software options.
The below-listed activities, those marked *reflect those activities which can have adverse statutory implications.
Stage 1 activities (including unethical) that can adversely impact business
• Strategic plans for design not aligned with the vision
• Develop a non-comprehensive design brief
• Skipping developing all preliminary designs
Stage 2 activities (including unethical) that can adversely impact business
Making compromises in the external and internal electrical designs by skipping or compromising on essential aspects such as those below.
• Design features External electrical works – (Diesel Generating sets, substations, High-speed diesel/fuel storage, and distribution, Electrical distribution system and backup system, ACB-Air circuit breakers, VCB-vacuum circuit breakers, Panels, bus bars, General lighting, power layouts, and illuminations, distribution boards, switches, Fire doors, Access controls, CCTV, Public address system, telephones, building management system, MATV (Master Antenna Television system), Security system, wi-fi, Solar lighting system, inverter, UPS
• Design features Internal electrical works (Wirings, Fixtures and fittings, Distribution system, rising mains, MS conduits, insulated conductors, Panels, etc.)
• National and international standards for quality
• Specifications of BOQ material
• Tolerances on workmanship vis a-vis installation and commissioning
• Not incorporating comprehensive Quality requirements
• Not considering comprehensive Design-related construction processes for external and internal electrical works
• Without considering standardization leading to higher costs
• Inaccurate Bill of quantities for each design area /no off
• Not factoring in acceptance criteria for Electrical design work in process and completed area
• MEP designer or consultant Insisting on specific brands of BOQ -both external electrical and internal electrical items. *
• Compromising specifications for developing samples in collusion with vendor/contractor*
• Using unlicensed software while developing Electrical designs.
• Issuing of design and drawings to Electrical (external or internal) contractor at project site without any version control *
• Not shredding waste designs/drawings or not deleting obsolete /old soft drawings*
Stage 3 activities (including unethical) that can adversely impact business
• Not incorporating all requirements vis a vis Statutory approval and sanctioned design/drawings*
• Bribing mandatory Agencies that approve the safety-related specifications of electrical design works relevant for issuing safety certificates *
• Contractors influence certifying agencies to compromise on certification in return for favors. *
Stage 4 activities (including unethical) that can adversely impact business
• Making tenders that are not comprehensive vis-à-vis technical specifications or are deliberately stated vaguely for subsequent manipulations amongst the MEP team members and contractors with ulterior motives. *
• In the tender, the MEP consultant/employees /engineers include names and brands of specific materials only for pre-identified /preferred vendors of the BOQ materials and MEP designers in return for commission or kickback from such vendors. *
• MEP designers recommend only a single source for many BOQ materials, thus leaving very few options for the project materials team to negotiate prices aggressively in return for commission /kickback to MEP designers from such vendors.
• Tender drawings do not incorporate applicable quality standards for all works.
• Tender drawings not incorporating applicable Statutory requirements vis-à-vis applicable National/International codes w.r.t safety. *
Stage 5 activities (including unethical) that can adversely impact business
• Making construction drawings inaccurate by not obtaining or not incorporating inputs from interfacing functions into various design elements for MEP plans
• Preparing coordinated drawings for each of the relevant External and internal Electrical work scope items vis designs and drawings without factoring inputs from the Architect team, Interior design team
• Using unlicensed software while developing MEP drawings
Stage 6 activities (including unethical) that can adversely impact business
• Validating designs without proper incorporation of all proposed connected power consumption points at different progressive loads or estimated occupancy of constructed areas or pro-rata electrical power consumption over a period
• Considering inaccurate proposed power factor & proposed power sanction /KVA*
• Inadequate vetting of design efficacy and drawings developed vis-à-vis specification of BOQ materials and installation requirements.
• Colluding the main MEP consultant and validating the design consultant to accept the design work with incorrect design calculation in return for some favors.
Stage 7 activities (including unethical ) that can adversely impact business
• Estimating costs based on thumb rules rather than considering detailed working vis a vis each BOQ item (e.g. Generators, ACB, VCB, Cables, Panels, Lights and fixtures, etc.), their quantity, and estimated rates based on tender documents, designs & drawings-external electrical works and internal electrical works
• Not considering installation, testing, and commissioning costs
Stage 8 activities(including unethical) that can adversely impact business
• Making “As-built drawings”
without verification of actual supply and installation of each BOQ material for external and internal electrical works*