Unit 18 Principles of Electrical Design & Installation Unit 18 Electrical Services

Assignment Brief

Student Name

ID Number

894626

Unit Number and Title

Unit 18 Principles of Electrical Design & Installation

Assignment Title

Unit 18 Electrical Services

Academic Year

25/25

Assessor

Submission Date

04/04/2026

IV Name  

IV Date

Issue Date

11/11/2025

Vocational Scenario or Context

Your client is an upcoming electrical installation, wishing to compete for the electrical installation for a prestigious company headquarter complex to accommodate their expanding organisation.

The proposed new building will involve A new 24m high office block, arranged over 6 floors, 5 floors of office accommodation above ground and a basement level gym and swimming pool.).

The building requires a server room on the ground floor and all floors will multiple desks equipped internet access.

The server room is critical to the company operations and requires an uninterruptable Electrical supply to the four duals redundant server’s systems.

The building also requires an emergency lighting system along with an alarm system suitable for the complete building

ACTIVITY 1

In your capacity as an assistant designer for a building services firm, specialising in electrical works, you have been asked to prepare a report investigating. The application of transformers in building services. A report with detailed explanation of the operation of AC Transformers.

Identify and explain difference between iron and copper losses within a transformer and explain how they are minimized

Investigate the Earthing and bonding requirements of BS 7671 and explain what is meant by Bonding metal equipment in bathrooms and kitchens of metal accessories and why it is important.

Investigate The use of uninterruptable power supplies that are required for the server room and possible use for critical desks situated throughout the building.

ACTIVITY 2

In your capacity as an assistant designer for a building services firm, specialising in electrical works, you have been asked to prepare a report that includes illustrations.

• Investigate the electrical distribution within the building and the layout of the feeders and distribution boards.

• Identify the boundaries between the DNO and Electrical Maintenance Company

• Investigate the Earthing and bonding requirements of BS 7671 and illustrate the various methods.

• With the use of diagrams explain the operation of MCB’S and how the protection requirements of BS7671 are satisfied using MCB’s of the correct rating.

• Describe and illustrate how Residual circuit protection are used to earth fault protection.

ACTIVITY 3

Within a Building Services installation, there are a variety of motors used for different applications.

Explain With the aid of a diagrams the operation of brushless electrical machines illustrating their winding connections and their operating characteristics and the relationship between back emf, armature current, torque, power, and speed.

The armature of a permanent-magnet dc generator has a resistance of 1 Ω and generates a voltage of 50 V when the speed is 500 r/min. If the armature is connected to a source of 150 V, calculate the following:

• The starting current
• The counter-emf when the motor runs at 1000 r/min. At 1460 r/min.
• The armature current at 1000 rpm. At 1460 rpm.
• The torque developed at 1000/r/min at 1460 rpm.
• The efficiency at 1000/r/min at 1460 rpm.
• Discuss the implications on the above for the primary distribution system.

The operation of AC machines requires the production of a rotating magnetic explain with aid of diagrams and circuit block diagrams how this achieved using inverters in modern electric traction systems.

Investigate the advantages of permanent magnet Synchronous and explain why these are now forming the basis of all electric traction systems

ACTIVITY 4

Explain what is meant by reactive power and why power factor correction equipment is required in premises which have an electrical load which has high reactive power demand.

You are required to determine the Reactive Power Compensation required for a load of 10Kw operating with power factor of 0.8 to improve the Power Factor to 0.95 and describe how this correction could be achieved.

ACTIVITY 5

Prepare a presentation of how miniature circuit breakers function detailing their operating characteristics and how residual circuit breaker’s function and their application.

Calculate the assumed current demand for the following circuits which are installed in a small Hotel.

a) Lighting load – Upstairs = 10.2A, Cable length = 20m

• Downstairs = 6.8A, cable length =40m
• Outside = 5.1A, cable length =60m

b) A 10Kw cooker

c) Justify your selection of MCB, s to project the above circuits.

d) Determine The Voltage drop.

e) Discuss what is meant by discrimination when related to circuit breaker tripping times

ACTIVITY 6                                   

The office measures 10 x 7 m with floor to ceiling height of 3 m.

The desk height is 0.8 m (working plane). The office requires an average illuminance of 500 lux.

The ceiling paint is emulsion paint on acoustic tiles (0.7), the walls are plastered and painted mid- grey (0.45 – 0.5) and the carpet floor tiles are dark grey (0.14)   

Calculate how many lamps/luminaires are needed to illuminate the working plane. 

The above office is located 20m from the distribution board, determines the electrical load of lighting installation and the possible voltage drop in the electrical cables.

The office is approximately 10m by 7m determine the optimal layout of luminaries to determine uniformity of luminance and ensure that the space/height ratio is satisfied and comment on the efficiency of the lighting system.       

Determine a lighting design for the pool area of 10m x 5m located in the basement of a house requiring an approximate lighting level 0f 500 lux.

• The electrical load
• The number of lighting circuits and the voltage drop on each circuit.

A possible layout for the distribution board along with MCB’s required for each circuit.