Lesson Notes By Weeks and Term v4 - SHS 3
ELECTRICAL SYSTEMS DESIGN
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ELECTRICAL SYSTEMS DESIGN
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Subject: Applied Technology
Class: SHS 3
Term: 2nd Term
Week: 12
Grade code: 2.4.1.LI.11
Strand code: 4
Sub-strand code: 1
Content standard code: 2.4.1.CS.1
Indicator code: 2.4.1.LI.11
Theme: ELECTRICAL AND ELECTRONIC TECHNOLOGY
Subtheme: ELECTRICAL SYSTEMS DESIGN
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In Ghana, almost every home, school, and business relies on electricity. However, we often face issues like lights not working, sockets having no power, or circuit breakers tripping ("light off"). Knowing how to safely identify and troubleshoot these common problems is a vital skill. This lesson introduces the systematic process of servicing basic electrical wiring circuits. It is not just about fixing a problem; it's about doing it safely and logically to prevent electrical shocks, fires, and further damage to appliances. This knowledge empowers you to maintain your home's electrical system safely and provides a foundation for a career as a professional electrician.
A. Foundational Principle: SAFETY FIRST!
Before touching any electrical circuit, safety is the number one priority. Failure to follow safety rules can lead to severe injury or death. De-energize the Circuit: Always go to the main distribution board (consumer unit) and turn OFF the main switch and the specific circuit breaker (MCB) for the circuit you are working on. Lockout/Tagout: If possible, place a lock or a clear sign ("DANGER: DO NOT SWITCH ON") on the breaker to prevent someone from accidentally turning it back on. Test for Dead: Use a multimeter or a voltage tester to confirm that there is NO voltage in the circuit you are about to work on. Use Insulated Tools: Always use tools with insulated handles (screwdrivers, pliers) in good condition. Wear Personal Protective Equipment (PPE): Wear dry safety boots (rubber-soled) and avoid wearing any metallic jewellery. Never Work Alone: Always have someone nearby who can help in case of an emergency.
B. The Four-Step Servicing Process
Servicing an electrical circuit is a logical process. We follow these four steps in order: Identify the Type of Circuit Identify the Nature of the Fault Outline and Perform Tests Solve the Problem (Rectification)