Basic Electrical Safety in the Workplace LIN155 PDF

Basic Electrical Safety in the Workplace LIN155 – Electronic Lab & Instrumentation Techniques School of Electronics and Mechanical Engineering Technology (SEMET) Textbook references: Chapter 1 p. 8-13, 17-20 Chapter 13 p. 240-241, 253-262 Agenda Types of electricity...

Basic Electrical Safety in the Workplace LIN155 – Electronic Lab & Instrumentation Techniques School of Electronics and Mechanical Engineering Technology (SEMET) Textbook references: Chapter 1 p. 8-13, 17-20 Chapter 13 p. 240-241, 253-262 Agenda Types of electricity Static electricity Current electricity How electricity works How is electricity distributed Transmission Lines Electrical Plugs Electrical workplace safety 2 Types of Electricity Static Electricity Example: Lightning Current Electricity Direct Current (DC) Alternating Current (AC) Image Source: https://www.britannica.com/science/lightning-meteorology Image source: https://s-media-cache-ak0.pinimg.com/736x/eb/05/7b/eb057b4404e574faa5f423832315e56e--energy-comparison-electrical-maintenance.jpg 3 Static Electricity Static electricity is a stationary electric charge, typically produced in friction between different materials. Example: Rubber shoe soles sliding across a carpet. Two polarities of electricity are produced: one on the carpet, the other on the shoe soles. The two materials attract each other, trying to reconnect. If they do not reconnect and the person touches a doorknob, the static electricity quickly transfers or discharges to the doorknob in a “spark”. Image source: https://sciencebob.com/wp-content/uploads/2014/11/StaticCan21.png Image source: https://hec-r.s3.amazonaws.com/Site/prod/contentplayer/templates/kids/images/static.jpg 4 Current Electricity For current to flow, there must be a closed circuit. A circuit consists of 3 essential elements: 1. a source of energy that supplies the voltage to make the current flow (eg. battery) 2. a user of electricity (eg. light bulb) 3. a transmission line to conduct electricity (eg. wire) For current to stop, the closed circuit path must open. A safe circuit contains an element that can turn it off. 4. a safety device to turn off current (eg. switch, fuse) Image source: https://www.teachengineering.org/content/cub_/activities/cub_electricity/cub_electricity_lesson03_activity1_header_image_new.jpg 5 Current Electricity - Understanding Identify the circuit elements in the diagrams below: Image source: https://s-media-cache-ak0.pinimg.com/736x/9e/13/de/9e13dee965853565d5918a39f73c2f05.jpg 6 How Electricity works Electricity flows through the path of least resistance. Given a choice of high resistance or low, electricity will always flow through a ground wire. (eg. lightning rod) Note: Flammable agents found in work environments can be ignited by electrical sparks and static electricity. Image source: Lightning strikes Toronto's CN tower (youtube.com) https://www.youtube.com/watch?v=JWkDrQNiMVw&t=5s 7  How Electricity is Distributed (1) Image source:: https://www.eia.gov/energyexplained/electricity/delivery-to-consumers.php 8  How Electricity is Distributed (2) Image source: http://3.bp.blogspot.com/-MqQtcVTVC-g/T1L7DwdXPRI/AAAAAAAAAKU/AerZTmfu6JA/s1600/STL.jpg 9 Transmission Lines Why don’t birds get electrocuted while sitting on live wires? Birds become temporarily charged but no current flows through their bodies. If they touch ground (a neutral wire or grounded pole) at the same time as the live wire, they will get shocked! Image source: https://www.youtube.com/watch?v=GJobqY4uH0c 10  Electrical Plugs 3-prong plugs are “ground” plugs. The two electrical blades allow AC electricity to flow. The large round prong is the ground. 2-prong plugs offer no protection against electric shock. There are some specially approved appliances and tools that may use a 2-prong plug. In these cases, the protection is double-insulated inside the equipment, not through a grounding wire or prong. Image source: https://s-media-cache-ak0.pinimg.com/originals/72/c1/cd/72c1cd1bed345ce2c6e21aa7361f7a20.jpg 11  Electrical Workplace Safety (1) Never use electrical equipment when any part of your body is standing on or near fluids. Wires or cables that are cracked, frayed, cut, or damaged must be replaced. Image source: https://www.hsetraining.org/safe-work-place-when-working-with-electrical-equipment/, Image source: https://weeklysafety.com/blog/office-electrical-hazards 12 Electrical Workplace Safety (2) Never place electrical cords where they can be tripped over or receive excessive wear. Keep cords away from heat and liquids. Avoid kinking, crushing, or binding cords. Do not pull on the cord of an electrical plug. Image source: https://blog.interpower.com/infopower/safety-sense-with-cords 13 Electrical Workplace Safety (3) Inspect cords and cables frequently for wear. Do not overload any electrical circuits. Avoid using octopus adapters. Extension cords must be of the same thickness and rating as the equipment cord. Do not use defective electrical equipment if it becomes excessively warm or hot. Unplug the equipment if it begins to smoke, even if it gives you a mild shock. Image source: http://www.fire-extinguisher101.com/class-c-fires.jpg Image source: https://osha-safety-training.net/product/faulty-wire-can-start-a-fire-safety-poster/ 14 Questions 15 Works Cited Digital-2000 – Safety Media Education – ww.digital-2000.com. Accessed 07 Apr 2024. Naked Science Scrapbook – Why are birds not electrocuted on power lines – youtu.be/rN3QhtnlCSw. Accessed 07 Apr 2024. 16