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# Electrical Safety at Construction Site

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Basics of Electrical Safety at Construction Sites
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### Electrical Safety at Construction Site

1. 1. Electrical Safety By GSG
2. 2. What is the definition of a shock absorber? A careless electrician.
3. 3. Recall Basics of Electricity 1. Voltage 2. Amperage (Current) 3. Resistance 4. Circuit  Series  Parallel
4. 4. What is "voltage"? Voltage is a measure of the electrical force that seems to push the current along. The symbol for voltage is "V".
5. 5. What is "voltage"?  Think of voltage as a lot of water stored in a high water tank.  Because the water tank is high, the water will have more force behind it as it flows down the water pipe.  This is why they put water tanks up high! If the same tank was placed at ground level, the water pressure would not be as great.
6. 6. What is “Amperage"?  Amperage is the unit used to measure the amount of electrical current.  Amperage is often referred to as "current" by electrical workers and engineers.  The symbol for amperage is "I".
7. 7. Let's go back to the water tank.  If diameter of the pipe coming from the water tank is large, a lot of water (amperage) will flow through the pipe.  If the pipe's diameter is small, a smaller amount will of water flow.  If you need a lot of current to operate the equipment, you'll need large wires to run the current. What is "amperage"?
8. 8. What is “Resistance"?  Resistance is the unit (ohms) used to measure the opposition to the flow of electrical current.  It's that simple. In an electrical circuit, components are usually sources of resistance.  Any component that heats up due to electrical current is a source of resistance. The symbol for resistance is "R".
9. 9. What is a "circuit"?  A circuit is the complete path for the flow of current.  Electrical current may flow through a circuit in a series or parallel path.
10. 10. What's a "series" circuit? For example, water from high in the mountains may flow down one stream (series) into a river that flows into the ocean.
11. 11. What is a Parallel Circuit ? Ex: The water flowing from a water falls on a hill will flow through many different water branches (parallel) before it reaches the ocean.
12. 12. Common Mistakes at Construction Sites
13. 13. Common Mistakes in Construction sites
14. 14. Common Mistakes in Construction sites
15. 15. Common Mistakes in Construction sites
16. 16. Common Mistakes in Construction sites
17. 17. Common Mistakes in Construction sites
18. 18. Common Mistakes in Construction sites
19. 19. Common Mistakes in Construction sites
20. 20. Common Mistakes in Construction sites
21. 21. Common Mistakes in Construction sites
22. 22. Common Mistakes in Construction sites
23. 23. Common Mistakes in Construction sites
24. 24. Common Mistakes in Construction sites
25. 25. Types of Electrical Injuries
26. 26. What kills – Voltage or Current ?  A common phrase heard in reference to electrical safety goes something like this: "It's not Voltage that kills, it’s Current!"  While there is an element of truth to this, there's more to understand about shock hazard than this simple adage.  If voltage presented no danger, no one would ever print and display signs saying: “ DANGER - HIGH VOLTAGE”
27. 27. How a Electrical shock occur ?  The principle that "current kills" is essentially correct. It is electric current that burns tissue, freezes muscles, and fibrillates hearts.  However, electric current doesn't just occur on its own; there must be voltage available to motivate electrons to flow through a victim.  A person's body also provide resistance to current, which must be taken into account.  Obviously, the more voltage available to cause electrons to flow, the easier they will flow through any given amount of resistance. Hence, the danger of high voltage.
28. 28. Hazards of Electricity Shock Arc Blast
29. 29. Effects of Electricity on the Human Body The four major types of electrical injuries are: Direct  Electrocution  Electrical Shock  Burns Indirect  Falls
30. 30. Electrocution Vs Electrical Shock  ‘Electrocuted’ and ‘Electrical Shock’ aren’t always interchangeable.  ‘Electrocuted’ can only be used when an electrical shock results in death.  If death does not occur, the term ‘shocked’ should be used.
31. 31. Electric Shock The electric shock is caused by a current passing through the body. The lethality of an electric shock is dependent on:  Current (the higher the current, the more likely it is lethal);  Duration (the longer the duration, the more likely it is lethal);  Voltage (the higher the voltage, the more likely it is lethal);  Pathway (if current flows through the heart muscle it is more likely to be lethal).
32. 32. Severity of Electrical Shock  The severity of injury from electrical shock depends on the amount of electrical current and the length of time the current passes through the body.
33. 33. Electrical Shock  Touching a live wire and an electrical ground will cause a shock.  Touching two live wires of different voltages will cause electrical shock.
34. 34. Electrical Shock Electric shock is the passing of electric current through the body. The electrical current may  Prevent you from releasing your grip from a live conductor.  Throw you into contact with a higher voltage conductor.  Cause you to lose your balance and fall.  Cause severe internal and external burns.  Kill you.
35. 35. Electrical Injuries The most common shock-related, nonfatal injury is a burn. Burns caused by electricity may be of three types:  Electrical burns,  Arc burns, and  Thermal contact burns.
36. 36. Electrical Burns An electrical burn is a burn that results from electricity passing through the body causing rapid injury. For a burn to be classified as electrical, electricity must be the direct cause.
37. 37. Arc Flash  An arc flash is a release of energy caused by an electric arc. The flash causes an explosive expansion of air and metal. The blast produces  A dangerous pressure wave  A dangerous sound wave  Extreme heat & Extreme light.
38. 38. Arc Flash  Temperatures as high as 35,000 F have been reached in arc-blasts.  These dangers can result in blast injuries, lung injuries, ruptured eardrums, shrapnel wounds, severe burns, and blindness and can also result in death.
39. 39. Thermal Contact Burns Thermal contact burns can occur when electricity ignites combustible material. Thermal contact burns occur when skin comes in contact with overheated electric equipment, or when clothing is ignited in an electrical incident.
40. 40. What route avoids your heart? Right hand to left hand Right hand to right foot Right hand to left foot Left hand to right foot Left hand to left foot Always use your right hand when working with live power- and keep your left hand in your pocket!
41. 41. What is Electrical Hazard? An electrical hazard can be defined as: A dangerous condition where a worker could make electrical contact with energized equipment or a conductor, and from which the person may sustain an injury from shock; and/or, There is potential for the worker to receive an arc flash burn, thermal burn, or blast injury due to the electrical contact.
42. 42. Protection Against Electrical Hazards Most electrical accidents result from one or more of the following three factors:  Unsafe equipment or installation,  Unsafe environment,  Unsafe work practices. Some ways to prevent these accidents are through the use of insulation, guarding, grounding, electrical protective devices, and safe work practices.
43. 43. The Electrical Safety Model What Must Be Done to Be Safe? To make sure all employees are safe before, during and after electrical work is performed, electrical workers should follow the three-step process. Electrical Safety Model: 1. Recognize hazards 2. Evaluate risk 3. Control hazards
44. 44. How do your recognize hazards? The first step toward protecting yourself is recognizing the many hazards you face on the job. To do this, you must know which situations can place you in danger. Some examples to recognize hazards. Inadequate wiring. Exposed electrical parts. Overhead power lines. Electrical systems and tools that are not grounded or double-insulated. Damaged power tools and equipment . Using the wrong PPE & Wrong Power Tool. Overloaded circuits. Wires with bad .
45. 45. Evaluating the Risks  After you recognize a hazard, your next step is to evaluate your risk from the hazard. The closer you work to the "danger zone," the more likely you'll be exposed to the electrical hazard.  Wet conditions combined with other hazards also increase your risk. You will need to make decisions about the nature of hazards in order to evaluate your risk and do the right thing to remain safe.  Another factor increasing your risk of injury is working around combinations of hazards.
46. 46. Evaluating the Risks (Contd..) There may be important clues that electrical hazards exist.  For example, if a GFCI keeps tripping while you are using a power tool, that's a clue that there is a problem. A GFCI that trips indicates there is current leakage from the circuit.  Don't keep resetting the GFCI and continue to work. You must evaluate the "clue" and decide what action should be taken to control the hazard.  A cable, fuse box, or junction box that feels warm may indicate too much current in the circuits.
47. 47. Evaluating the Risks (Contd..) Some examples of evaluating the Risks.  Tripped circuit breakers.  Blown fuses.  An electrical tool, wire, or connection that feels warm.  A burning odor of electrical tools, cables, switches etc;  Damaged insulation.  Worn, frayed, or damaged insulation. Any of these conditions, or "clues," tells you something important: There is a risk of fire and electrical shock. The equipment or tools involved must be avoided or rectified.
48. 48. Control the Hazards How Do You Control Hazards? In order to control hazards, you must first create a safe work environment, then work in a safe manner. Generally, it is best to remove the hazards altogether and create an environment that is truly safe. Use as many safeguards as possible. If one fails, another may protect you from injury or death.
49. 49. Earthing & Grounding Earth is used for the safety of the human body in fault conditions while Grounding (As neutral earth) is used for the protection of equipment. Earthing is a preventive measure while Grounding is just a return path. Earthing is accomplished through bonding of a metallic system to earth. It is normally achieved by inserting ground rods or other electrodes deep inside earth. Grounding means connecting the live part to the earth (for example neutral of power transformer).
50. 50. Electrical Protection Installation of Circuit Breakers & GFCI: Circuit Breaker is provided to protect equipment, where as GFCI (Ground Fault Circuit Interrupter) is provided to protect the people.
51. 51. Provide Double Earthing Provide double Earthing is required for welding machine & electrical tools: Double earthing gives low resistance and also if any one earth is out of order, second will do the required work of earthing the equipment.
52. 52. De-energize circuits  Treat all conductors as if they are energized until they are locked out and tagged.  Always test a circuit to make sure it is de-energised before working on it.
53. 53. (Lock-Out / Tag-Out) LOTO  Lockout/Tag-out is an essential safety procedure that protects workers from injury while working on or near electrical circuits and equipment.  Lock-out involves applying a physical lock to the power source(s) of circuits and equipment after they have been shut off and de-energized.
54. 54. Provide proper enclosures Prevent exposure to live electrical parts by isolating them.
55. 55. Use correct size of cables Prevent overloaded wiring by using the right size and type of wire.
56. 56. Use Proper testing appliances Use approved portable meters and leads, not improvised test lamps.
57. 57. Close unused openings Unused openings in panels, cabinets, boxes and fittings must be effectively closed.
58. 58. Take proper precautions while working near overhead power lines. Best Safety Practice:  Survey the site for overhead power lines.  Never get closer than 10 feet to an overhead power line!  If work beneath live OH power lines cannot be avoided, barriers, and warning notices should be provided.
59. 59. Safety precautions during Welding  Connect electrical equipment and work piece correctly.  Use the correct cable size.  Make sure all electrical connections are tight, clean, and dry.  Insulate yourself from work piece and ground.  Remove metal jewelry.  Use proper PPE.
60. 60. Other General Factors  Ensure that the locations of all buried electrical cables are marked before work begins on any excavation.  You can prevent electrical shocks in two ways; de- energizing the circuit prior to work or using safety equipment on the energized circuit.  Ensure all rotating machinery components are protected with proper guards. (Like chains, belts, wheels, fans etc).  Do not work in wet conditions.  Do not attempt to carry out repair works by yourself even if it is of minor nature.
61. 61. Summary  Electrical accidents don't happen without cause. Sometimes it's equipment failure; Other times, it's operator failure.  Electrical accidents are often fatal. No device that will provide 100% protection.  Regardless, properly using required safety equipment might reduce the seriousness of electrical shocks.  Take the necessary time to properly plan a job, it may help avoid later delays caused by an accident.  Working with electricity can be dangerous. However, electricity can be safe if properly respected.