Class: Senior Secondary School 2 (SS2 / SSS 2)
Term: Third Term
Week: 3
Age: 16 years
Duration: 45 minutes
Subject: Basic Electricity
Curriculum Theme: Electrical Installations
Previous Lesson: Hand Tools and Testing Implements: Identification and Application.
Topic: TYPES OF ELECTRICAL WIRING
Subject Matter: Meaning of electrical wiring (definition), types of wiring (surface wiring, conduit wiring, trunking, ducting)

Specific Objectives

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

Cognitive Domain:

Define electrical wiring.
List and explain at least four types of electrical wiring systems.
State the advantages and disadvantages of each wiring type.

Affective Domain:

Appreciate the importance of choosing the correct wiring system for different applications.
Show interest in observing practical demonstrations of wiring.

Psychomotor Domain:

Identify different materials used in various wiring systems.
Observe a practical demonstration of surface wiring.

Participate actively in discussions about different wiring methods.
Work collaboratively to identify suitable wiring types for given scenarios.

Reference Materials

The following resources were used in planning this lesson:

Senior Secondary Schools Education Curriculum
State Unified Scheme of Work
Basic Electricity for Senior Secondary Schools by P.N. Okoro

Instructional Materials

The teacher will teach this lesson with the aid of:

Wiring board
Assorted cables (e.g., PVC insulated cables, twin-with-earth)
Conduit pipes (PVC and metallic)
Trunking sections
Ducting sections
Wiring tools (pliers, screwdrivers)
Chalkboard/Whiteboard and marker/chalk
Diagrams of different wiring systems

Rationale for the Lesson

Understanding different types of electrical wiring is important for pupils to comprehend how electrical installations are done safely and effectively. This knowledge helps them identify appropriate wiring systems for various buildings and purposes, contributing to electrical safety awareness.

Prerequisite/Previous Knowledge

Pupils should have basic knowledge of electricity, including concepts of conductors, insulators, and simple electrical circuits.

Lesson Content/Board Summary

TYPES OF ELECTRICAL WIRING

Meaning of Electrical Wiring

Electrical wiring refers to the system of conductors, insulating materials, and components used to safely distribute electrical power from the main supply to various points in a building or structure. It includes cables, conduits, trunking, switches, sockets, and other accessories.

Types of Electrical Wiring Systems

There are several types of electrical wiring systems, each with its own characteristics, advantages, and disadvantages:

1. Surface Wiring (Cleat Wiring)

In this system, insulated cables are run on the surface of walls or ceilings, supported by cleats made of porcelain, wood, or plastic. It is a temporary and inexpensive wiring method.

Advantages:
- Easy to install and modify.
- Low cost.
- Easy to locate faults.
- Requires less skilled labour.
Disadvantages:
- Poor aesthetic appearance.
- High risk of mechanical damage to cables.
- Not suitable for permanent installations.
- Risk of fire if not properly installed.

2. Conduit Wiring

This system uses conduits (pipes) to protect the electrical cables. Conduits can be made of PVC or metal. There are two main types:

Surface Conduit Wiring: Conduits are installed on the surface of walls and ceilings.
Concealed Conduit Wiring: Conduits are hidden within the walls or under plaster, providing a neat appearance. This is the most popular method for modern buildings.

Advantages:
- Provides excellent protection to cables from mechanical damage, moisture, and fire.
- Aesthetically pleasing (especially concealed conduit).
- Durable and long-lasting.
- Safe for use in residential and commercial buildings.
Disadvantages:
- High initial cost.
- Installation is complex and time-consuming.
- Difficult to modify or add new connections (especially concealed).
- Fault location can be challenging.

3. Trunking System

Trunking is a system where cables are enclosed in rectangular or square sections of metal or PVC. It is often used in commercial and industrial environments where many cables need to be routed together.

Advantages:
- Provides good protection for cables.
- Allows for easy addition or removal of cables.
- Neat and organized appearance for multiple cables.
- Suitable for large installations.
Disadvantages:
- Higher cost than surface wiring.
- Can be bulky and less aesthetic in certain settings.
- Requires careful planning for bends and junctions.

4. Ducting System

Ducting systems are similar to trunking but are typically larger and often installed under floors (floor ducts) or in ceilings (ceiling ducts) to carry a large number of power and communication cables. They are common in offices, data centers, and large commercial buildings.

Advantages:
- Excellent protection for a very large number of cables.
- Allows for future expansion and cable management.
- Cables are completely concealed, offering a clean appearance.
- Provides easy access to cables for maintenance.
Disadvantages:
- Very high installation cost.
- Installation is complex and requires specialized skills.
- Difficult to modify once installed.
- Requires significant space within the building structure.

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 then introduces the new topic by asking pupils how electricity gets to their homes and offices.
Pupils’ Activity: Pupils respond to the teacher’s questions and settle down for the lesson.
Learning Point: Pupils are prepared for the new lesson and connect it to previous knowledge.

Step 2: Meaning of Electrical Wiring

Time: 7 minutes
Teaching Skill: Explanation/Definition
Teacher’s Activity: The teacher defines electrical wiring and explains its purpose in distributing power safely. The teacher writes the definition on the board.
Pupils’ Activity: Pupils listen attentively, ask questions, and copy the definition into their notes.
Learning Point: Pupils understand the fundamental concept of electrical wiring.

Step 3: Surface Wiring

Time: 7 minutes
Teaching Skill: Demonstration/Explanation
Teacher’s Activity: The teacher explains surface wiring, its uses, advantages, and disadvantages. The teacher then carries out a practical demonstration of surface wiring on the wiring board using cables and cleats.
Pupils’ Activity: Pupils observe the practical demonstration, ask questions, and take notes on the characteristics of surface wiring.
Learning Point: Pupils learn about surface wiring through both explanation and practical observation.

Step 4: Conduit Wiring

Time: 7 minutes
Teaching Skill: Explanation/Illustration
Teacher’s Activity: The teacher explains conduit wiring, differentiating between surface and concealed conduits. The teacher shows examples of PVC and metallic conduit pipes and discusses their advantages and disadvantages.
Pupils’ Activity: Pupils listen, examine the conduit samples, and note down the key features, advantages, and disadvantages.
Learning Point: Pupils understand the concept and types of conduit wiring systems.

Step 5: Trunking System

Time: 6 minutes
Teaching Skill: Explanation/Comparison
Teacher’s Activity: The teacher explains the trunking system, showing samples or diagrams of trunking. The teacher highlights its applications, advantages, and disadvantages.
Pupils’ Activity: Pupils observe the samples, ask clarifying questions, and record the information in their notes.
Learning Point: Pupils learn about the trunking wiring system and its suitability for various installations.

Step 6: Ducting System

Time: 6 minutes
Teaching Skill: Explanation/Differentiation
Teacher’s Activity: The teacher explains the ducting system, comparing it to trunking, and discusses its primary uses, advantages, and disadvantages, especially in large commercial settings.
Pupils’ Activity: Pupils listen, take notes, and ask questions to clarify the differences and applications of ducting.
Learning Point: Pupils understand the ducting system and its specific applications.

Step 7: Evaluation/Review

Time: 5 minutes
Teaching Skill: Questioning/Assessment
Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

What is electrical wiring?
Mention any three types of electrical wiring systems.
State two advantages of conduit wiring.
Identify one major disadvantage of surface wiring.

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 main points of the lesson, emphasizing the importance of choosing the correct wiring system for safety and efficiency. The teacher gives an assignment to pupils to draw and label diagrams of any two wiring systems discussed.
Pupils’ Activity: Pupils listen to the summary and copy down the assignment.
Learning Point: Pupils consolidate their learning and are given tasks to reinforce understanding.

Lesson Keywords

Electrical wiring – The system of conductors and components used to distribute electrical power.
Surface wiring – Wiring where cables are run on the surface of walls, supported by cleats.
Conduit wiring – Wiring where cables are protected inside pipes (conduits).
Trunking – A system enclosing cables in rectangular sections, often for multiple cables.
Ducting – Large enclosures for many cables, often installed under floors or in ceilings.
Cleats – Supports used to hold cables in surface wiring.

Differentiation

For struggling learners, the teacher will provide simplified diagrams and focus on identifying the main types of wiring. For advanced learners, the teacher will encourage discussions on factors influencing the choice of wiring systems and potential safety implications of incorrect installations.

Note for teachers using this lesson plan

Teachers should ensure that all practical demonstrations are carried out safely. Emphasize the safety aspects associated with each wiring type. Encourage pupils to ask questions and relate the concepts to electrical installations they see around them.