WORKSHOP PRACTICE

1. WORKSHOP PRACTICE Lab No. 3 Electrical Accidents & Safety Precautions

2. Today’s Lab • What is an Electrical Accident? • How to avoid Electrical Accidents? • Safety Precautions • Safety Regulations • Safety Signs

3. Electrical Accident • Any unwanted action which takes place in a maximum of three seconds is referred to as an accident. • If due to any reason current starts flowing in the human body then an electrical accident is said to have taken place.

4. Electric Shock • Electrical shock occurs when a person comes in contact with two conductors of a circuit or when the body becomes part of the electrical circuit. • In either case, a severe shock can cause the heart and lungs to stop functioning. Also, severe burns may occur where current enters and exits the body.

5. Electrical Accident • Human body receives shock • Time up to 10 seconds • Two types of waves produced • Electrostatic Waves • Electromagnetic Waves

6. Types of Waves • Electrostatic Waves (ESW) • If the current is flowing through a conductor, it will produce Electrostatic waves. • Electromagnetic Waves (EMW) • If we have two parallel conductors and current is flowing through them, then electromagnetic waves are produced between these conductors.

7. Ranges of Resistance • The electric wire insulation has a resistance up to 3 MΩ. • Human body resistance ranges (1400-2000)Ω. • During electric shock, resistance decreases to 10 Ω. • Heavy current flows through human body.

8. Effects of Shock on Human Body • Due to decrease in human body resistance heavy current flows. • It damages the cardiac and respiratory systems. • Paralysis Problem

9. Three Phase Voltages • In power house 3-phase voltages are generated. • The three phases are equal in magnitude but out of phase by 120o each. • 3-Phase Configurations • Star Configuration. • Delta Configuration.

10. Types of Electrical Accidents • Phase to Ground (Single Phase) • When human body touches phase line while standing on the ground. • Phase to Phase (Double Phase) • When human body touches two phases. • Three Phase • When human body is in contact with 3 phases at a time.

11. How to avoid Electrical Accidents • Respect all voltages • Prevention is the best medicine for electrical shock. • Do not take chances. • Have a knowledge of the principles of electricity and follow safe work procedures.

12. Safety Precautions • A safety precaution is a measure that you take to avoid any injury/ harm to either yourself or anyone/thing in your surroundings. • Be careful. • Use common sense • A commodity which the legislators think is in short supply and not very common. • Stop and think before you act. • Ask the technical staff for advice.

13. Workshop Safety Precautions • Protective Equipment • Use goggles and breathing masks. • Tidiness • Dispose of sharp objects, blades, glass shards in suitable containers - Ensure the workshop is tidy. • Machinery • Make sure machinery is properly installed, levelled and are periodically maintained or serviced.

14. Clothing and Personal Protective Equipment

15. Safety Precautions to avoid Electrical Accidents • Don’t touch the person who is still in contact with live conductor. • Live wire connection. • Grounding. • Insulation strength. • Plug point disconnection. • Switches-to avoid open, unprotected ends of wire. • Use fuses & other protective devices to avoid damage to the equipment.

16. Grounding • To connect the neutral of an electrical system to the ground is called grounding. • Electrical equipment safety. • Internal and external factors make the electric system unbalance, to avoid this distortion and damage to the system.

17. Safety Regulations • Insulation • It is a material which does not allow the flow of electrons. • Dielectric strength of the insulation. • Grounding • Electrical equipment should be properly grounded. • Equipment Status • Good condition • Use proper equipment for the job. • Personal Experience • Any person, whether experienced or not, involved in an activity is called personal. • Experience is of great importance.

18. Safety Regulations • Personal Mental Condition • Sound mental condition. • Should not be mentally disturbed. • Personal Knowledge • Should be properly trained for the activity, he has to perform. • Ambient Conditions • The conditions under which the equipment works efficiently. • Current rating, Voltage rating, Frequency, Temperature.

19. Who to do when an electrical accident has occurred? • Free the victim from contact with the electricity in the quickest, safest way. This step, while it must be taken quickly, must be done with great care; otherwise, there may be two victims instead of one.

20. First aid for Electric Shock • Sometimes victims of electrical shock suffer cardiac arrest or heart stoppage as well as loss of breathing. • The process by which a person who has stopped breathing can be saved is called artificial ventilation (respiration). • The purpose of artificial respiration is to force air out of the lungs and into the lungs, in rhythmic alternation, until natural breathing is reestablished.

21. Clean up your mess! • It is the responsibility of ALL Laboratory and Workshop users to keep the surrounding work area clean and tidy at all times. • At the end of the session, everyone is supposed to bring the equipment in their proper places.

22. Safety Signs • Safety Signs are the symbols which • Prevent accidents. • Signal health hazards. • Indicate the location of safety, first aid and fire protection equipment

23. Safety Signs Stop and Prohibition Sign Caution (Warning) Sign

24. Safety Signs Emergency-related information signs Mandatory (must obey) signs

25. Lab Report Format Experiment No. 2 Title: “To study Vernier Caliper, Micrometer, SWG and to measure diameter of different wires and depth of different items.” Apparatus Theory Figure/ Circuit Diagrams Procedure Observations & Calculations Conclusions/ Comments

26. Lab Report Submission Last date of submission of Lab 1,2 & 3 is Monday,9th November till 1:00 p.m. in Workshop Lab.