Lesson Notes By Weeks and Term v5 - Grade 10

Lesson Video

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Performance objectives

• Identify 5 key workshop safety hazards
• Correctly use 3 different hand tools
• Safely operate an electric power tool
• Use a multimeter to measure V, I, and R
• Explain the importance of Personal Protective Equipment (PPE)

Lesson summary

Electrical Technology is a hands-on subject, and a significant portion of your learning will occur within the workshop environment. Understanding workshop safety is paramount. Not only is it vital to your personal well-being and the well-being of others, but it also ensures that you can use electrical tools and measuring instruments effectively and responsibly. In South Africa, where many communities rely on skilled electricians for maintenance and development, safe work practices are crucial to prevent accidents and ensure reliable electrical installations.

Lesson notes

2.1 Workshop Safety Safety is the number one priority in any electrical workshop. Ignoring safety protocols can lead to serious injury or even death.

Here are some essential safety practices: Housekeeping: Keep your workspace clean and organized. Loose wires, tools left on the floor, and spills are all tripping hazards. Clean up spills immediately.

Electrical Hazards: Be aware of live electrical components. Never work on live circuits unless absolutely necessary, and only then with proper authorization and using appropriate lock-out/tag-out procedures. Assume all circuits are live until proven otherwise with a multimeter.

Personal Protective Equipment (PPE): Always wear appropriate PPE. This includes safety glasses (to protect your eyes from flying debris), insulated gloves (to protect you from electric shock), and safety shoes (to protect your feet from falling objects and electrical hazards). Overalls are also recommended.

Tool Safety: Use the right tool for the job. Using the wrong tool can damage the tool, the workpiece, or yourself. Ensure tools are in good working condition before use. Damaged tools should be reported and taken out of service.

Fire Safety: Know the location of fire extinguishers and how to use them. Be aware of flammable materials in the workshop and keep them away from heat sources. Know the emergency evacuation procedures.

Reporting Accidents: Report any accident or near-miss immediately to your teacher or supervisor. Even seemingly minor incidents should be reported to prevent future problems.

Lock-out/Tag-out Procedures: If you are working on a circuit that needs to be de-energized, use lock-out/tag-out procedures to ensure that no one accidentally re-energizes the circuit while you are working on it. This involves placing a lock and a tag on the circuit breaker to indicate that the circuit is being worked on.

Example: Imagine you are replacing a light fixture in a classroom. Before you start, you must switch off the circuit breaker that controls that light fixture. To prevent someone from accidentally turning it back on while you're working, you should use a lock-out/tag-out device. The lock prevents the breaker from being switched on, and the tag identifies who is working on the circuit and why. 2.2 Common Hand Tools Screwdrivers: Used for tightening or loosening screws. Common types include flat-head (slotted), Phillips, and Pozidriv. Always use the correct size and type of screwdriver for the screw to avoid damaging the screw head.* Pliers: Used for gripping, cutting, and bending wires and components. Common types include combination pliers, long-nose pliers, and diagonal cutting pliers (side cutters). Never use pliers on live circuits unless they are insulated and rated for the voltage.* Wire Strippers: Used for removing insulation from wires without damaging the conductor. Use the correct gauge setting for the wire size to avoid nicking or breaking the wire.* Wrenches (Spanners): Used for tightening or loosening nuts and bolts. Common types include open-end wrenches, box-end wrenches, and adjustable wrenches (crescent wrenches). Use the correct size wrench to avoid damaging the nut or bolt.* Hammers: Used for driving nails and other fasteners. Always wear safety glasses when using a hammer.*

Example: You need to connect two wires together. First, you would use wire strippers to remove the insulation from the ends of the wires. Then, you would use combination pliers to twist the wires together to form a secure mechanical connection. Finally, you might use electrical tape to insulate the connection. 2.3 Common Power Tools Electric Drill: Used for drilling holes in various materials. Always wear safety glasses and use the correct drill bit for the material being drilled. Secure the workpiece before drilling.* Angle Grinder: Used for cutting, grinding, and polishing metal. Always wear safety glasses, a face shield, and gloves when using an angle grinder. Use the correct grinding wheel for the material being worked on.*

Example: You are installing a new electrical outlet. You need to drill a hole in the wall to run the wires. You would use an electric drill with a suitable drill bit to create the hole. Make sure to check for any existing pipes or wires behind the wall before drilling! 2.4 Measuring Instruments Multimeter: A versatile instrument used to measure voltage (V), current (I), and resistance (R). It can measure both AC and DC quantities.

Voltage Measurement: Connect the multimeter in parallel with the component or circuit you want to measure the voltage across. Select the appropriate voltage range (AC or DC) and the correct voltage level.

Example: To measure the voltage across a resistor, connect the red lead of the multimeter to one end of the resistor and the black lead to the other end.

Current Measurement: Connect the multimeter in series with the circuit you want to measure the current through.