Class: Senior Secondary School 1 (SS1 / SSS1)
Term: 3rd Term
Week: 10
Age: 15 years
Duration: 45 minutes
Subject: Electrical Installation and Maintenance Work
Curriculum Theme: Technology
Previous Lesson: The Relevant Regulation: IEE Regulation on Protective Devices.
Topic: THE IEE REGULATION
Subject Matter: Importance of IEE regulation, IEE regulation on protective devices, meaning of earthing, functions of earthing in circuit breaker installations, identifying earth rod and earth lead.

Specific Objectives

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

Cognitive Domain:

State the importance of IEE regulations in electrical installations.
List IEE regulations concerning protective devices.
Define earthing in electrical circuits.
Explain the functions of earthing in circuit breaker installations.

Affective Domain:

Appreciate the importance of adhering to safety regulations in electrical work.
Value the role of earthing in preventing electrical hazards.
Show willingness to follow IEE guidelines during practical work.

Psychomotor Domain:

Identify an earth rod and an earth lead.
Demonstrate how to refer to IEE regulation handbooks for relevant rules.

Discuss the collective responsibility of electricians in ensuring electrical safety.
Collaborate in identifying safety measures in electrical systems.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum (Senior Secondary Education)
State Unified Scheme of Work for Electrical Installation and Maintenance Work SSS 1
Electrical Installation Technology for Senior Secondary Schools by E.O. Okoro
https://www.elexp.org/what-is-iee-regulation-for-electrical-installation/

Instructional Materials

The teacher will teach this lesson with the aid of:

Earth rod
Earth lead
Earthing diagram
IEE regulation handbook reference charts

Rationale for the Lesson

This lesson helps pupils understand the essential rules and standards that ensure safety in electrical installations. Knowing these regulations and the proper application of earthing prevents electrical accidents and ensures that electrical systems operate safely and correctly, protecting both users and equipment.

Prerequisite/Previous Knowledge

Pupils should have basic knowledge of electrical circuits, common electrical components, and the concept of electricity flow.

Lesson Content/Board Summary

THE IEE REGULATION AND EARTHING

Importance of IEE Regulations

The Institution of Electrical Engineers (IEE) Regulations provide standards for safe electrical installation. Adherence to these regulations is important for several reasons:

To ensure the safety of persons from electric shock and burns.
To protect property from damage by fire or excessive temperatures arising from electrical installations.
To ensure that electrical installations are correctly designed, installed, inspected, and maintained.
To ensure the efficient and reliable operation of electrical systems.

IEE Regulations on Protective Devices

IEE regulations mandate the use of appropriate protective devices in all electrical installations to automatically disconnect the supply in case of a fault. Common protective devices include:

Fuses: Overcurrent protective devices that melt and break the circuit when current exceeds a safe level.
Circuit Breakers: Automatic electrical switches designed to protect an electrical circuit from damage caused by overcurrent or short circuit.
Residual Current Devices (RCDs) / Earth Leakage Circuit Breakers (ELCBs): Devices that quickly break an electrical circuit to prevent serious harm from an ongoing electric shock.

The regulations specify the correct rating, type, and placement of these devices for different circuits and loads.

Meaning of Earthing

Earthing (or grounding) is the process of connecting the non-current-carrying metallic parts of an electrical installation to the general mass of the earth. This connection provides a low-resistance path for fault currents to flow directly to the earth, preventing dangerous voltages from building up on equipment enclosures.

Functions of Earthing in Circuit Breaker Installations

Earthing plays a critical role in the safe operation of circuit breaker installations by:

Protecting against Electric Shock: It provides a safe path for fault current to flow to the earth, causing protective devices (like circuit breakers or RCDs) to trip and disconnect the supply, thus preventing electric shock to persons touching faulty equipment.
Protecting Equipment from Damage: It helps to dissipate surge currents and lightning strikes safely to the earth, protecting sensitive electrical equipment from damage.
Ensuring System Stability: It helps to maintain stable voltage levels in the electrical system and provides a reference potential.
Facilitating Operation of Protective Devices: A good earth connection ensures that enough fault current flows to activate overcurrent protective devices (fuses, circuit breakers) quickly when an earth fault occurs.

Identifying Earth Rod and Earth Lead

Earth Rod: A long metallic rod (usually copper or steel, sometimes copper-clad) driven deep into the ground to provide a direct electrical connection to the earth. It is typically visible where it enters the ground near the electrical service entrance.
Earth Lead (Earthing Conductor): A green-and-yellow insulated copper conductor that connects the earth rod (or main earthing terminal) to the metallic enclosures of electrical equipment, consumer units, and sockets within the installation.

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. The teacher then introduces the topic by asking pupils about the importance of safety rules in everyday life, relating it to electrical safety.
Pupils’ Activity: Pupils respond to questions and listen attentively.
Learning Point: Pupils are prepared for the lesson and understand its relevance to safety.

Step 2: Explanation of IEE Regulation Importance

Time: 7 minutes
Teaching Skill: Explanation/Discussion
Teacher’s Activity: The teacher explains what IEE regulations are and discusses their importance in ensuring safety and proper functionality of electrical installations, using examples of accidents that can be prevented.
Pupils’ Activity: Pupils listen, ask questions, and contribute to the discussion on the importance of safety.
Learning Point: Pupils understand why IEE regulations are necessary.

Step 3: Discussion of IEE Regulations on Protective Devices

Time: 8 minutes
Teaching Skill: Elucidation/Demonstration
Teacher’s Activity: The teacher lists and explains IEE regulations concerning common protective devices like fuses, circuit breakers, and RCDs. The teacher may display relevant diagrams or charts from the IEE handbook.
Pupils’ Activity: Pupils observe the diagrams, take notes, and ask questions about the protective devices.
Learning Point: Pupils identify various protective devices and their role according to IEE regulations.

Step 4: Definition of Earthing

Time: 5 minutes
Teaching Skill: Definition/Visualisation
Teacher’s Activity: The teacher defines earthing using simple terms and displays a diagram of an earthing system to help pupils visualize the concept.
Pupils’ Activity: Pupils observe the diagram, listen to the definition, and write down notes.
Learning Point: Pupils understand the meaning of earthing.

Step 5: Functions of Earthing in Circuit Breaker Installations

Time: 8 minutes
Teaching Skill: Explanation/Illustration
Teacher’s Activity: The teacher explains in detail the various functions of earthing, particularly its role in protecting against electric shock and ensuring the effective operation of circuit breakers during a fault.
Pupils’ Activity: Pupils listen, ask clarifying questions, and record the functions of earthing.
Learning Point: Pupils grasp the critical functions of earthing in electrical safety.

Step 6: Identification of Earth Rod and Earth Lead

Time: 7 minutes
Teaching Skill: Demonstration/Identification
Teacher’s Activity: The teacher displays an actual earth rod and earth lead (if available) or clear images, guiding pupils to identify and differentiate between them and explaining their purpose.
Pupils’ Activity: Pupils observe the materials and identify the earth rod and earth lead.
Learning Point: Pupils can visually identify key components of an earthing system.

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

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

State two reasons why IEE regulations are important in electrical installations.
Mention two common protective devices used in electrical circuits as per IEE regulations.
What is earthing in electrical installations?
List three functions of earthing in circuit breaker installations.
Describe how to identify an earth rod and an earth lead.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 5 minutes
Teaching Skill: Summarization/Assignment
Teacher’s Activity: The teacher briefly summarizes the key points of the lesson and gives pupils an assignment to research specific IEE regulations for domestic wiring.
Pupils’ Activity: Pupils listen to the summary and copy the assignment.
Learning Point: Pupils consolidate their learning and prepare for further study.

Lesson Keywords

IEE Regulation – Standards set by the Institution of Electrical Engineers for safe electrical installations.
Protective Devices – Components like fuses, circuit breakers, and RCDs that disconnect power during faults.
Earthing – Connecting metallic parts of an electrical installation to the earth to provide a safe path for fault currents.
Earth Rod – A metallic rod driven into the ground to provide an earth connection.
Earth Lead – A conductor connecting electrical equipment to the earth rod or main earthing terminal.

Differentiation

For pupils who grasp concepts quickly, the teacher can encourage them to research specific IEE regulation numbers related to the topics discussed. For pupils needing more support, the teacher can provide simplified diagrams and allow peer-assisted learning during identification tasks. Practical demonstrations will benefit kinesthetic learners.

Note for teachers using this lesson plan

Ensure that actual examples or clear visual aids (diagrams, charts, or real components) of earth rods, earth leads, and protective devices are available for demonstration. Emphasize the practical implications of not following IEE regulations, such as electrical hazards and equipment damage. Encourage pupils to consult the IEE handbook for specific details and to develop a habit of referring to standards.