Construction Technology: Electrical Services Assignment

This assignment presents a comprehensive electrical services design for a proposed mixed-use office development. It begins with an overview of power reticulation, detailing the supply from the transformer to individual consumer units and distribution boards, including the use of a canalis busbar trunking system for the office area. The design incorporates a switch room, generator room for backup power, and provisions for postpaid meters. The assignment covers lighting design, specifying lux levels for various areas, and proposes the use of LED lighting with occupancy sensors for energy efficiency. Emergency lighting, outdoor lighting, and provisions for lifts are also addressed. A fire detection system, including BMS compatibility, is detailed. The assignment culminates in electrical calculations, determining the demand for various components such as lift motors, pumps, lighting, and air conditioning, culminating in the total electrical load for the office block, including an allowance for future expansion. The document is a practical application of electrical engineering principles in a construction context.

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CONSTRUCTION TECHNOLOGY: ELECTRICAL SERVICES
Student’s Name
Course
Professor’s Name
Institutional Affiliation
City/ State
Date

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Power Reticulation
Mains power will be provided in the premise from the transformer and metered by the
local power distribution company. Power reticulation will be aided by the use of LV switchboard
in a switch room located near the entrance of the building next to the guardhouse. This will be
supplied directly from the transformer, from which power will be distributed to individual
consumer units and distribution boards through cables which will then run to individual rooms in
cable trays or trunking via the riser duct in the development. The canalis busbar trunking system
should be used for power distribution in the office area since it is less expansive and this will
ensure flexibility and will provide a neat finish (Renton, Barclay, and Tremain 2015). No
overhead power lines shall be used within the development for safety purposes.
Power Design
The switch room, generator room, and associated equipment and controls will be located
in the basement area. A provision for a postpaid meter will be made. The entire development
will run on generator during power outages.
The power from the meter will terminate in the consumer units located in each of the
office floors from where each rented space will draw their power. Lighting, power and other
appliance circuit breakers from the consumer units shall be indicated in the drawings. All extra
breaker locations will be covered by a blanking plate.
13A socket circuitry will be provided in each office space terminating in the consumer
unit with provisions for the required appliance utilization. The hot water heaters and the cooker
circuits will also be provided as required in the kitchenette. The circuit arrangement will allow

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separation of floors, lights, and sockets all in carefully selected clusters for power management
and phase balancing.
Large rocker, screw-less switches shall be used for switching positions in the office,
while the medium rocker switches will be used in the remaining spaces. Twin socket-outlets
shall be provided as appropriate in all the spaces. We propose the use of good quality European
brands such as MK, Schneider, Crabtree or Legrand brand ranges as the preferred high-end
electrical fitting selection. These switches shall be BMS Compatible for ease of control and
safety from cyber threats.
Backup power
Generators will provide back up to the entire development. The proposed generator room
will be located on the basement floor. This will allow for easier accessibility to enable
installation, operation, and maintenance whereas also preventing the development from
excessive noise exposure.
Lighting Design
Gate lights providing a minimum of 250 lux will be provided at the entrances as per
lighting and illumination standards (Chizari, Jamali, Abdollahramezani, Salehi, and Dargahi
2017).
Lighting will be provided to a minimum of 150 lux for lobbies, corridors, and
washrooms. The office area will be provided with 500 lux while service corridors and stores to
be provided with 150 lux. The guardhouses will be illuminated at 300 lux. We propose that the
future paint lab be illuminated at 1000 lux. The proposed lighting is LED lighting with a

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minimum power factor of 0.9 be considered in all areas for energy efficiency. In the Kitchenette,
recessed LED downlighters will be used to highlight design features. All areas not engaged with
direct office use like the storerooms, washrooms and ATM room have occupancy sensors. A mix
of LED strip lights and LED round lights with a minimum power factor of 0.9 for the staff
walkways and corridors be considered for energy efficiency and for aesthetic value. LED Panels
and indirect lighting be considered in the offices' space areas. Wall-mounted lights and
downlighters with a dimmer switch will be considered in the training areas if one will be
integrated into the office building. LED downlighters will be considered in the storerooms.
Washrooms will have IP 54 rated ball fittings to protect the bulbs from coming into contact with
the moisture in these areas. Separate IP 54 rated mirror lights will be provided above wash hand
basin mirror locations.
Considerations will be made for incorporating motion sensors in the corridors and
washrooms and occupancy sensors in the non-selling spaces to promote energy efficiency. 2-way
switching will be provided where areas served are expansive or allowing switch on for entry and
exit to rooms switch off. This will be implemented in the office space, the staff entrance area,
and at the staircase. Socket outlets will be provided in all required spaces to enable the use of
equipment and appliances needed in all the spaces. The lights shall be powered via a canalis
busbar trunking system for ease of coordination with the Mechanical Engineer on the design and
installation of the sprinkler system. The lights shall be on BMS hence the lighting controls shall
be BMS Compatible.

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Emergency Lighting
Emergency lighting will be incorporated in the design to allow decent visibility during
power failure and changeover to the generator. This would reduce the panic effect and allow
shoppers to find their way in instances of prolonged outage beyond the 18–25 seconds of
changeover (Johnson, Mavis, Marques, Patel, and Altenburger 2018). Emergency lights with an
emergency kit (battery pack) are installed. These will be 10% of the lights installed according to
the standard BS5266 Part 11999 (Nag, 2019): which defines that emergency lighting should
provide 10% of the normal lighting level at the hazard, with a minimum of 15 Lux. (This
minimum is unlikely ever to be a problem, as it would only be valid if the risk area had a normal
illumination level less than 150 lux).
Emergency signages will be provided at all escape routes with a minimum level of 5 lux.
Escape route emergency lighting will be color-coded as per fire regulation standard and ISO
3864 and BS 5266, which refers to the provision of Escape Lighting (Bernardini 2017).
Outdoor Lighting
Outdoor lighting will be connected to the main outdoor circuit. Wall-mounted lights on
the perimeter wall will be used for this purpose. The outdoor lighting fixture newly installed
shall be shielded so that it does not produce a strong, direct light beyond the property boundaries
and the light emitted shall be white in color.
Illuminated signage shall be incorporated on the main entrance to ease identification of
the office block and for aesthetic value. Lights on the external wall, entrance, and terraces should
be of the same family.

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Street lighting will also be provided in the outdoor parking area and at the periphery of
the building. Consideration for solar-powered street lights should be made for energy efficiency
since it helps to cut down on power bills once the development is operational and it also helps in
reducing the trenching and cabling costs. Photocell or time clock controls should be incorporated
in the street lighting system.
Lifts
Power provisions will be made to supply the lifts. The table size will be 3.048m ×
1.524m, the power requirement is between 7.5hp to 10hp and the working height is assumed to
be the vertical height of the building in meters (Faulconbridge, Cass, and Connaughton 2016).
Fire detection
Fire Detection system shall conform to BS 5839 Part 1 which entails Fire
detection and fire alarm systems for buildings – Part 1: Code of practice for design, installation,
commissioning and maintenance of systems in non-domestic premises (Abdullah, Bertalan,
Masar, Coskun, and Kale 2017).
The development will be served by a BMS Compatible addressable fire detection system
where every detector will be linked to the main panel in the surveillance room and the repeater
panel will be located at the guardhouse. Specific detectors to be installed will depend on the area
of use, i.e. heat detectors in the kitchenette and smoke detectors in the banking area, trading area,
offices and the training areas. Aspirating detectors will be used in the trading area as per the
standard BS EN 54-20:2006 which specifies the requirements, test methods and performance
criteria for aspirating smoke detectors for use in fire detection and fire alarm systems installed in
buildings. Break glasses at every exit point and one sounder on each floor shall be provided. The

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fire panels will be provided with an automatic telephone link to both the fire brigade and the
Security company (Nkurunziza, Pendleton, and Chun, 2019).
A 24hour monitored guardhouse located at the entrance and exit of the office building
will assist in preventing an intrusion into the premise. BMS Compatible IP CCTV cameras shall
be installed to cover all areas with the NVR located in the surveillance room. The system will
cover all external entrances and office corridor areas.
Biometric System shall be BMS Compatible and will be installed in the management
offices. A BMS Compatible disabled alarm kit will also be installed in the disabled washrooms
with the panel at the surveillance room. BMS Compatible burglar alarm kit in the storerooms
with the strobe light installed at the gatehouse and vibration sensors on the windows of the
building’s exterior.
Electrical Calculations
Lift motors and ancillaries; the motors are assumed to be 3-phase.
Starting current=120A
Power,P= √3 VI
P= √3 × 400 V × 120 A
P=83.14 KVA
Pumps, ancillary motors; the motors are assumed to be 3-phase.
Number of pumps=30
Pump motor current rating=5A each

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Therefore, the total current =5 ×30=150 A
Power,P= √3 VI
P= √3 × 400 V × 150 A
P=103.923 KVA
Fire detection equipment
1 GPO=10A, 230V
Therefore, Power, P= 4 ×230 V ×10 A
P¿ 9.2 KVA
Hot water units
4.8 kW per unit (1No. units per floor)
Thus, Number of unis=1 × 4=4 units
P= 4 × 4.8 kW
P= 19.2 KW
Assuming a power factor of 0.8 for each hot water unit (Park, Park, Kim, Shin, and Kim 2013;
P= 19.2 ×1000
0.8
P=24 KVA

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Lift lobby
Total power required =1500watts. Taking a power factor of 0.8;
P= 1500
0.8
P=1.875 KVA
Office and basement power
This is calculated based on the floor areas of the respective spaces.
Floor Area (square metres)
Ground floor 2361
Level 1 1818
Level 2 1445
Level 3 1054
Basement 1 1478
Basement 2 1478
Total 9634
Power outlets are positioned in such a way that each outlet covers an entire area of 200 square
metres (Nakagawa, Moriya, Suwa, Fujimoto, Arakawa, and Yasumoto 2017).
Thus, the number of outlets= 9634
12 =802.83(Approximately 803 Outlets)
Power requirements for the outlets, P= 230 V × 803 Outlets ×10 A
P= 1,847 KVA
Exterior and advertisement lighting
Power required is 5000Watts. Taking a power factor of 0.8;

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P= 5000
0.8
P=6.25 KVA
Plant room lighting
250 lux is required for the plant room. Assuming the plant room area is equal to retail area=21
square metres;
From rapid tables; 58.333 Watts (0.05833kW) is required. Taking a power factor of 0.95;
P= 58.333
0.95
P=0.0614 KVA
Office and toilets lighting
400 lux is required in these areas. From rapid tables (Grigsby 2018);
Office area Power Total Power
Ground floor 5680+4813.33 10493.33 W
Level 1 4226.67+3853.3+1960 10039.97 W
Level 2 3311.11+3111.11+906.67 7328.89 W
Level 3 2480+2204.44+862.2 5546.66 W
Total 33,408.85 W
Taking a power factor of 0.95;
P= 33408.85
0.95
P=35.166 KVA

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Air conditioning for the office
The total office area is approximated to be 6,678 square metres and 150W per metre is typical.
This power rating includes even ventilation fans.
Total power; P=150 Watts ×6678 square metres
P=1001.7 kW
Taking 0.8 as the power factor;
P= 1001.7
0.8
P=1252.125 KVA
Total electrical load
This is taken as the sum of all the above which amounts to 3369.3434KVA. This is the electrical
demand for the office block which is approximately 3.36934 MVA.
a) Allowing for 10% for future expansion
P=3.36934 MVA ×10 %=3.7 MVA

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Reference List
Abdullah, S., Bertalan, S., Masar, S., Coskun, A. and Kale, I., 2017, July. A wireless sensor
network for early forest fire detection and monitoring as a deciding factor in the context of a
complex integrated emergency response system. In 2017 IEEE Workshop on Environmental,
Energy, and Structural Monitoring Systems (EESMS) (pp. 1-5). IEEE.
Bernardini, G., 2017. Fire Safety of Historical Buildings: Traditional Versus Innovative
“Behavioral Design” Solutions by Using Wayfinding Systems. Springer.
Chizari, A., Jamali, M.V., Abdollahramezani, S., Salehi, J.A. and Dargahi, A., 2017. Visible
light for communication, indoor positioning, and dimmable illumination: A system design based
on overlapping pulse position modulation. Optik, 151, pp.110-122.
Faulconbridge, J.R., Cass, N.F. and Connaughton, J., 2016. Standards, design and energy
demand: The case of commercial offices.
Grigsby, L.L., 2018. The Electric Power Engineering Handbook-Five Volume Set. CRC press.
Johnson, J.C., Mavis, D.W., Marques, A., Patel, G.P. and Altenburger, R., ABL IP Holding LLC,
2018. Powering an emergency lighting system. U.S. Patent Application 16/009,587.
Nag, P.K., 2019. Lighting Systems. In-Office Buildings (pp. 371-404). Springer, Singapore.
Nakagawa, E., Moriya, K., Suwa, H., Fujimoto, M., Arakawa, Y. and Yasumoto, K., 2017,
March. Toward real-time in-home activity recognition using indoor positioning sensor and power
meters. In 2017 IEEE International Conference on Pervasive Computing and Communications
Workshops (PerCom Workshops) (pp. 539-544). IEEE.

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Nkurunziza, D., Pendleton, P. and Chun, B.S., 2019. Optimization and kinetics modeling of
okara isoflavones extraction using subcritical water. Food Chemistry, 295, pp.613-621.
Park, T., Park, C., Kim, B., Shin, H. and Kim, E., 2013. Flexible PEDOT electrodes with large
thermoelectric power factors to generate electricity by the touch of fingertips. Energy &
Environmental Science, 6(3), pp.788-792.
Renton, A.C., Barclay, G.J. and Tremain, M.C., Preformed Line Products Co, 2015. Electrical
connections for high voltage electrical distribution and/or reticulation. U.S. Patent 9,083,092.