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Electrical safety - Hazards and Controls
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- 2. Agenda 1 2 Introduction Hazards 3 Control Measures 4Legal Requirements 5 Site Practices SN 2
- 3. An Important Quote… Concernfor Man Himself and for His Safety must always from the chief interest of all technical endeavor. SN 3
- 4. Introduction Electricity is theset of physical phenomena associated with the presence and motion of matter that has a property of electric charge. SN 4
- 5. Basic Principles Electric currentalways flows throug a conductor. Always passes through a conductor. Ultimately reaches into the earth surface. SN 5
- 6. Definitions Current Charge flowing througha conductor in unit time. Unit of measurement is Amp. Voltage It is a pressure from which the charge flowing through a conductor in unit time. Unit of measurement is Volt Resistance Resistance is any conditionwhich retards current flow. Unit is Ohms. SN 6
- 7. Hazards of Electricity •Electrical shock • Electrical fire • Flash over • Radiation • Explosion • Indirect effects SN 7
- 8. Hazards of Electricity •Electrical Shock Shock occurs when the body becomes part of the electric circuit. - Contact with Both Wired of the Electric Circuit - With one wire of an energized circuit and the ground - Touching Energized Metallic Part and standing on Ground SN 8
- 9. Hazards of Electricity •Electrical Fire Fire in an Electric Circuit happens because of the following reasons. - Over Loading. - Incorrect Fuses/Protective Devices. - Poor Maintenance SN 9
- 10. Hazards of Electricity •Explosion Electricity does not explode in itself but aids in causing explosion if; - Presence of explosive fumes/vapours. - Presence of flammable gas cylinders in the vicinity of the flames/arcs SN 10
- 11. Hazards of Electricity •Flash over An electric arc (sometimes referred to as “electrical flashover”) is a continuous electric discharge of high current which flows through an air gap between conductors. This generates - a very bright ultra-violet light - intensive heat. SN 11
- 12. Hazards of Electricity •Indirect effects Some of the indirect effect of electricity, when a person received electrical shock is; - Fall - Drowning - Cut & Abrasion SN 12
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- 15. Electrical Shock We Receiveelectrical shock, when our body becomes part of the electrical circuit. SN 15
- 16. Severity of ElectricalShock The severity of electrical shock depends on : 1. the path the current travels 2. the amount of voltage, and 3. the type of current (AC or DC).. SN 16
- 17. Alternate Current (AC)vs Direct Current (DC) (1) Current of 60 mA of AC can cause fibrillation (2) AC is more dangerous to our Heart (3) Four times severe than AC current (1) Current of 300–500 mA of DC can cause fibrillation (2) DC is more dangerous to our body. More likely to freeze the victim (3) Relatively Safer than AC current AC DC SN 17
- 18. Human Resistance toElectrical Current SN 18
- 19. Shock Protection Devices FuseUnit Miniature Circuit Breaker Earth Leakage Circuit Breaker ResidualCurrent Circuit Breaker Insulator Guarding Earthing PPEs SN 19
- 20. Legal and OtherRequirements Indian Electricity Act, 2003 Indian Electricity Rules, 2005 National Electricity Code SN 20
- 21. Legal and OtherRequirements, IE Rules, 2005 Rule-3: Authorisation Provides provisionfor authorizationby a supplier or a consumer Rule 29: Construction, Installation, Protection…… Ensure safety of human beings, animalsand property” The consumer shall also ensure that the installationunder his control is maintainedin a safe condition. Rule 30: Service Lines and Apparatuson ConsumerPremises…… Rule 31: Cut out at Consumer Premises…… Provide a suitable cut-out in each conductorof every service-line other than an earthed... Rule 35: Danger Notice…… Affix permanentlyin a prominentposition a danger notice in Hindi English or local language... SN 21
- 22. Legal and OtherRequirements, IE Rules, 2005 Rule-36: Handling of Electrical Supply Lines Stipulatesto ensure adequatesafety precautions before handlingof electric supply lines and apparatus Rule 41: Distinction of DifferentCircuits…… Meansof indication of permanent nature. Requirementof affixinginstructions for restorationof persons suffering from electric shock Rule 44: Instruction on Restorationof Personsreceiving electrical shocks…… Rule 44A: Notification of Accidents Information shall send to the Inspector a telegraphic report within 24 hours Rule 45: Precautions to be adopted by Consumer Measures to be adoptedby consumers, Owners, occupiers, electrical contractors, electrical workmen and suppliers… SN 22
- 23. Clearances to bemaintained….. SN 23
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- 30. And Finally… Make ita good Servant Not a Bad Master SN 30