Class: Senior Secondary School 1 (SS1 / SSS 1)
Term: First Term
Week: 11
Age: 15 years
Duration: 45 minutes
Subject: Electrical Installation and Maintenance Work
Curriculum Theme: Technology
Previous Lesson: Electrical Accessories: Meaning and Types.
Topic: PRACTICAL DRAWING OF A 3-BEDROOM APARTMENT ELECTRICAL PLAN
Subject Matter: Drawing a 3-bedroom apartment plan to scale, positioning electrical accessories on the plan, labeling accessories on a wiring drawing, basic layout planning for electrical points.

Specific Objectives

By the end of the lesson, pupils should be able to:

Cognitive Domain:

Explain the concept of scale drawing for electrical plans.
Identify appropriate locations for various electrical accessories in a 3-bedroom apartment.
Interpret common electrical wiring symbols.

Affective Domain:

Appreciate the importance of accurate electrical plan drawings for safety and functionality.
Develop an interest in planning efficient electrical layouts.

Psychomotor Domain:

Draw a basic 3-bedroom apartment plan to a given scale.
Position common electrical accessories at appropriate points on the drawn plan.
Label the positioned electrical accessories using standard symbols.

Share ideas on effective electrical layout planning within a domestic setting.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum for Electrical Installation and Maintenance Work.
State Unified Scheme of Work for Senior Secondary Schools.
Electrical Installation and Maintenance Work for Senior Secondary Schools 1 by [Author’s Name/Publisher].
https://www.electricaltechnology.org/2019/07/electrical-symbols.html
https://www.theengineerspost.com/electrical-drawing-symbols/

Instructional Materials

The teacher will teach this lesson with the aid of:

A large drawing board or whiteboard.
Rulers, pencils, and erasers.
Sample wiring symbols chart.
A pre-drawn example of a 3-bedroom apartment electrical plan.

Rationale for the Lesson

This lesson helps pupils understand how to plan and represent electrical installations accurately in a domestic building. It enables them to apply drawing skills to practical electrical work, ensuring future installations are safe, functional, and conform to standards.

Prerequisite/Previous Knowledge

Pupils are expected to have basic knowledge of drawing instruments, simple geometric shapes, and an understanding of common electrical components.

Lesson Content/Board Summary

Practical Drawing of a 3-Bedroom Apartment Electrical Plan

Scale Drawing for Electrical Plans

Scale drawing is a drawing that shows a real object with accurate sizes reduced or enlarged by a certain ratio (scale). For electrical plans, it allows for accurate representation of room dimensions and placement of fittings.

The following are reasons for using scale drawings:

To represent large areas on a smaller sheet of paper.
To maintain the correct proportion and relative positioning of components.
To facilitate accurate measurement and calculation of materials.

Electrical Accessories and Symbols

Electrical accessories are devices used in an electrical installation to control, protect, or connect circuits and appliances. Each accessory has a standard graphical symbol for use in drawings.

The following are common electrical accessories found in a 3-bedroom apartment:

Light points (ceiling roses)
Wall switches (one-way, two-way)
Socket outlets (13A, 15A)
Ceiling fan points
Water heater points

Positioning Electrical Accessories on the Plan

Positioning electrical accessories correctly on a plan ensures functionality, safety, and convenience for the occupants.

The following are considerations for positioning accessories:

Functionality: Place switches near doors, sockets near likely appliance locations.
Accessibility: Ensure switches and sockets are easily reachable and not obstructed by furniture.
Safety: Avoid placing sockets too close to water sources in bathrooms and kitchens.
Aesthetics: Position accessories neatly and uniformly where possible.
Regulations: Adhere to local wiring regulations and minimum height requirements.

Labeling Electrical Accessories

Labeling involves using standard symbols, numbers, and a legend to clearly identify each electrical accessory on the plan. This helps in understanding the circuit design, installation, and future maintenance.

The following are ways to label electrical accessories:

Use the correct BS/IEC electrical symbol for each accessory.
Number similar accessories (e.g., S1, S2 for switches) and provide a legend.
Indicate circuit connections where necessary (e.g., lighting circuits, power circuits).

Basic Layout Planning for Electrical Points

Basic layout planning involves deciding the number and location of all electrical points in each room to meet the anticipated needs of the occupants.

The following are key aspects of layout planning:

Determine lighting requirements for each room (general, task, ambient).
Identify potential locations for major appliances (TV, refrigerator, air conditioner).
Ensure adequate provision of socket outlets to avoid the use of extension cords.
Plan for future expansion or modifications.

Teaching Methods/Instructional Techniques

Discussion, Lecture, Demonstration, Question and Answer, Visual Aids

Instructional Procedures

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction
Teacher’s Activity: The teacher greets the pupils, reviews the previous lesson briefly, and introduces the new topic: “Practical Drawing of a 3-Bedroom Apartment Electrical Plan.” The teacher explains that this lesson is important for understanding how homes are wired safely and efficiently.
Pupils’ Activity: Pupils respond to greetings, recall previous lesson points, and listen attentively to the introduction of the new topic.
Learning Point: Pupils are prepared for the lesson and understand its relevance.

Step 2: Explanation of Scale Drawing

Time: 8 minutes
Teaching Skill: Explanation/Demonstration
Teacher’s Activity: The teacher explains what a scale drawing is and why it is used in electrical plans. The teacher demonstrates how to apply a simple scale (e.g., 1:100) to represent actual room dimensions on paper, using a segment of a wall as an example on the board.
Pupils’ Activity: Pupils listen, ask questions for clarification, and observe the demonstration of scale application.
Learning Point: Pupils understand the concept and importance of scale in drawing electrical plans.

Step 3: Drawing the Apartment Plan

Time: 10 minutes
Teaching Skill: Demonstration/Guided Practice
Teacher’s Activity: The teacher sketches a basic outline of a 3-bedroom apartment plan on the board, showing dimensions and room labels. The teacher guides pupils on how to start drawing their own apartment plan to scale using their rulers and pencils.
Pupils’ Activity: Pupils begin drawing the 3-bedroom apartment plan on their drawing sheets, following the teacher’s guidance and using the specified scale.
Learning Point: Pupils develop practical skills in drawing building plans to scale.

Step 4: Introduction to Electrical Accessories and Symbols

Time: 7 minutes
Teaching Skill: Explanation/Visual Aids
Teacher’s Activity: The teacher presents a chart of common electrical accessories and their standard symbols. The teacher identifies and explains the function of each accessory and its corresponding symbol, relating them to household use.
Pupils’ Activity: Pupils observe the chart, identify the symbols, and note down the names and functions of various accessories.
Learning Point: Pupils become familiar with common electrical accessories and their standard symbols.

Step 5: Positioning Electrical Accessories

Time: 8 minutes
Teaching Skill: Demonstration/Practical Application
Teacher’s Activity: The teacher demonstrates on the board how to position various electrical accessories (e.g., light points, switches, socket outlets) at appropriate locations on the apartment plan, explaining the reasons for each placement based on functionality and safety.
Pupils’ Activity: Pupils practice positioning the electrical accessories on their drawn apartment plans, applying the principles demonstrated by the teacher.
Learning Point: Pupils learn how to correctly place electrical accessories on a plan considering practical factors.

Step 6: Labeling Accessories

Time: 5 minutes
Teaching Skill: Explanation/Practical Application
Teacher’s Activity: The teacher explains the importance of clear labeling and demonstrates how to label the positioned accessories using the correct symbols and a simple legend on the board.
Pupils’ Activity: Pupils label the electrical accessories they have positioned on their plans, ensuring clarity and adherence to standard symbols.
Learning Point: Pupils understand the importance of and practice correct labeling of electrical accessories.

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

Define scale drawing as it applies to electrical plans.
List four common electrical accessories found in a 3-bedroom apartment.
State two important considerations when positioning electrical accessories on a plan.
Explain why it is necessary to label electrical accessories on a wiring drawing.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 2 minutes
Teaching Skill: Summarization
Teacher’s Activity: The teacher summarizes the key points of the lesson, emphasizing the importance of accurate drawing, correct positioning, and clear labeling in electrical installation planning. The teacher assigns homework for pupils to complete their apartment plans and research local wiring regulations.
Pupils’ Activity: Pupils listen to the summary, ask any final questions, and note down the homework.
Learning Point: Pupils consolidate their understanding and are aware of follow-up tasks.

Lesson Keywords

Scale Drawing – A drawing that represents a real object or area with accurate sizes reduced or enlarged by a specific ratio.
Electrical Plan – A technical drawing that shows the layout of electrical wiring, fixtures, and appliances in a building.
Accessories – Devices used in an electrical installation, such as switches, sockets, and light fittings.
Symbols – Standardized graphical representations used on electrical plans to denote different components.
Layout Planning – The process of determining the arrangement and positioning of electrical points to meet functional and safety requirements.

Differentiation

For pupils who are struggling, the teacher will provide pre-drawn room outlines or templates to assist with the initial drawing phase and offer more direct guidance during accessory placement. Advanced pupils will be challenged to include more complex circuits or research specific local electrical regulations that might influence their layout decisions.

Note for teachers using this lesson plan

Ensure all pupils have access to drawing tools. Encourage neatness and precision in their drawings. Emphasize the practical implications of incorrect positioning or labeling, especially regarding safety. Display a clear, large chart of electrical symbols for easy reference throughout the practical session.