Class: Senior Secondary School 1 (SS1 / SSS 1)
Term: Second Term
Week: 4
Age: 15 years
Duration: 45 minutes
Subject: Electrical Installation and Maintenance Work
Curriculum Theme: Technology
Previous Lesson: Distribution: Single Phase and Three Phase Overview.
Topic: SURFACE WIRING
Subject Matter: meaning of surface wiring, circuit diagram of a point of light controlled by a switch, identification of cables for power and lighting, clips and fixing methods for surface wiring

Specific Objectives

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

Cognitive Domain:

Define surface wiring.
Draw a simple circuit diagram of a point of light controlled by a switch.
Identify different types of cables used for power and lighting installations.
State various clips and fixing methods for surface wiring.

Affective Domain:

Appreciate the importance of selecting the correct cable for electrical installations.
Value safe wiring practices in surface installations.

Psychomotor Domain:

Sketch a basic circuit for a light point controlled by a switch.
Correctly identify and differentiate between power and lighting cables when presented with samples.

Participate actively in class discussions on wiring safety.

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 School Electrical Installation and Maintenance Work.
Electrical Installation and Maintenance Work for Senior Secondary Schools by A. O. Oladipo.
https://www.example.com/electrical_safety_guidelines
https://www.example.com/types_of_wiring_cables

Instructional Materials

The teacher will teach this lesson with the aid of:

Circuit diagram chart showing a light point controlled by a switch.
Cable samples (e.g., PVC insulated twin with earth cable, flexible cables).
Different types of clips (e.g., round PVC clips, flat PVC clips, saddle clips).
PVC nails/screws.
Whiteboard and markers.

Rationale for the Lesson

This lesson helps pupils understand a common method of electrical wiring used in homes and offices. Learning about surface wiring and correct cable identification is important for ensuring electrical safety and functionality in various installations.

Prerequisite/Previous Knowledge

Pupils should have basic knowledge of electrical terms such as circuit, switch, and lamp from their previous lessons.

Lesson Content/Board Summary

Surface Wiring

Meaning of Surface Wiring

Surface wiring is a type of electrical installation where cables are run directly on the surface of walls, ceilings, or other structures, rather than being concealed within them. The cables are secured using various clips and fixing accessories.

Circuit Diagram of a Point of Light Controlled by a Switch

A circuit diagram is a simplified visual representation of an electrical circuit. For a point of light controlled by a switch, the diagram typically shows the power source, a switch, a lamp, and the connecting wires. The switch is connected in series with the lamp to control the flow of current to it.

Identification of Cables for Power and Lighting

Cables are selected based on their current-carrying capacity, insulation, and intended use. Correct identification prevents overloading and ensures safety.

The following are common cables and their uses:

PVC Insulated Twin with Earth Cable (e.g., 1.5mm², 2.5mm²): Commonly used for fixed wiring installations in homes and offices.
- 1.5mm²: Often used for lighting circuits.
- 2.5mm²: Often used for power circuits (sockets).
Flexible Cables (e.g., 0.75mm², 1.0mm²): Used for connecting portable appliances to power outlets. Not typically for fixed surface wiring.
Conductor Colours:
- Live (Phase): Brown (formerly Red)
- Neutral: Blue (formerly Black)
- Earth: Green/Yellow (always Green/Yellow)

Clips and Fixing Methods for Surface Wiring

Clips and fixing methods are used to secure cables neatly and safely along surfaces.

The following are common clips and fixing methods:

PVC Round Clips: Used for round cables, secured with a PVC nail.
PVC Flat Clips: Used for flat twin-and-earth cables, secured with a PVC nail.
Saddle Clips: Metal or plastic clips used for securing larger diameter cables or conduits, often screwed into the surface.
Cable Ties: Used for bundling cables, but not for primary fixing to surfaces in permanent installations.
Screws and Wall Plugs: Used with saddle clips or when securing junction boxes and accessories.

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 and reviews the previous lesson briefly. The teacher then asks pupils if they have observed electrical wires running on the surface of walls in some buildings and introduces the topic: Surface Wiring.
Pupils’ Activity: Pupils respond to greetings, recall previous knowledge, and listen attentively to the introduction.
Learning Point: Pupils are prepared for the new lesson and connect it to real-world observations.

Step 2: Meaning of Surface Wiring

Time: 8 minutes
Teaching Skill: Explanation/Definition
Teacher’s Activity: The teacher explains the meaning of surface wiring, highlighting its characteristics as an exposed wiring method. The teacher uses examples of places where surface wiring is commonly found.
Pupils’ Activity: Pupils listen, ask questions for clarification, and note down the definition.
Learning Point: Pupils understand what surface wiring is.

Step 3: Circuit Diagram of a Point of Light Controlled by a Switch

Time: 10 minutes
Teaching Skill: Demonstration/Illustration
Teacher’s Activity: The teacher displays the circuit diagram chart showing a point of light controlled by a switch. The teacher explains each component (power source, switch, lamp, wires) and how they are connected to form a complete circuit.
Pupils’ Activity: Pupils observe the chart, listen to the explanation, and copy the diagram into their notes.
Learning Point: Pupils can identify components and understand the basic operation of a simple lighting circuit.

Step 4: Identification of Cables for Power and Lighting

Time: 10 minutes
Teaching Skill: Demonstration/Identification
Teacher’s Activity: The teacher displays various cable samples (e.g., 1.5mm² and 2.5mm² twin with earth PVC cables, flexible cables). The teacher explains how to identify them by size, insulation, and conductor colours, stating their common uses for power and lighting circuits.
Pupils’ Activity: Pupils observe the cable samples, touch them (if safe and appropriate), and identify the different types based on the teacher’s explanation. They also note the conductor colour codes.
Learning Point: Pupils can differentiate between cables used for power and lighting and know their standard colour codes.

Step 5: Clips and Fixing Methods for Surface Wiring

Time: 7 minutes
Teaching Skill: Explanation/Demonstration
Teacher’s Activity: The teacher displays different types of clips (round PVC clips, flat PVC clips, saddle clips) and explains their specific uses for securing different types of cables in surface wiring. The teacher briefly demonstrates how they are fixed.
Pupils’ Activity: Pupils observe the clips and fixing methods, ask questions about their application, and note down the types.
Learning Point: Pupils understand the various methods of securing cables in surface wiring installations.

Step 6: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

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

What is surface wiring?
Mention two types of cables used for fixed electrical installations.
State the standard colours for Live, Neutral, and Earth conductors.
List two common clips used for securing cables in surface wiring.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 7: Conclusion

Time: 5 minutes
Teaching Skill: Summarization
Teacher’s Activity: The teacher summarizes the key points of the lesson, reiterating the importance of correct cable selection and safe wiring practices. The teacher gives pupils homework to draw the circuit diagram of a light point controlled by a switch.
Pupils’ Activity: Pupils listen to the summary and copy down the homework assignment.
Learning Point: Pupils consolidate their understanding and are given a task to reinforce learning.

Lesson Keywords

Surface Wiring – An electrical installation method where cables are run visibly on the surface of walls or ceilings.
Circuit Diagram – A simplified drawing showing the connections and components of an electrical circuit.
Cable – An insulated conductor or group of conductors used to transmit electrical energy.
Clips – Devices used to secure cables to surfaces.
Live – The conductor that carries electric current from the source to the appliance.
Neutral – The conductor that completes the circuit by carrying current back to the source.
Earth – A safety conductor that provides a path for fault current to the ground.

Differentiation

For struggling learners, the teacher will provide simplified diagrams and allow more time for hands-on identification of cables and clips. Advanced learners can be challenged to research the advantages and disadvantages of surface wiring compared to other wiring methods or to identify cable ratings.

Note for teachers using this lesson plan

Teachers should ensure that all cable samples and instructional materials are safe to handle and clearly labeled. Emphasize safety precautions when discussing electrical installations. Encourage pupils to ask questions and participate in practical identification activities. The practical demonstration of fixing clips should be done with care and supervision.