بسم الله الرحمن الرحيم

1. بسم الله الرحمن الرحيم

2. Common Electrical Hazards In Industries Presented By Engr. Azfar A.Kaim Khani

3. Electrical Terminology • Power • Amount of energy used each second, measured in • watts • Current • The movement of electrical charge • Resistance • Opposition to current flow • voltage • Measure of electrical force • Risk • Chance that injury or death will occur • Shocking current • Electrical current that passes through a part of the body

4. Over-current protection device Device that prevents too much current in a circuit Qualified person Someone who has received mandated training on the hazards and on the construction and operation of equipment involved in a task Insulators Substances, such as wood, rubber and glass that have high resistance to electricity Grounding A conductive connection to the earth which acts as a protective measure Electrical Terminology Continued…

5. Short Circuit Low-resistance path between a live wire and the ground, or between wires at different voltages (called a fault if the current is unintended) tag-out Applying a tag that alerts workers that circuits and equipment have been locked out trip Automatic opening (turning off) of a circuit by a GFCI or circuit breaker Electrical Terminology Continued…

6. What is Electricity & how does it works Power in Electrical Circuit is: P = V x I Voltage [driving force] causes current to flow Current [flow of Electrons] Circuit / loop is necessary for current to flow

7. Circuit / loop is necessary for current to flow

8. Electrical Injuries There are four main types of electrical injuries: Direct: Electrocution or death due to electrical shock Electrical shock Burns Indirect - Falls

9. Hazard - Overhead Power Lines usually not insulated Examples of equipment that can contact power lines: Crane Ladder Scaffold Scissors lift Raised dump truck bed

10. Control - Overhead Power Lines Stay at least 10 feet away Post warning signs Assume that lines are energized Use wood or fiberglass ladders, not metal Power line workers need special training & PPE

11. Injury to a person may be in the form of: Electric Shock Burns Fire Eye Injuries

12. Electrical Shock Received when current passes through the body Severity of the shock depends on: Path of current through the body Amount of current flowing through the body Length of time the body is in the circuit

13. Dangers of Electrical Shock Currents above 10 mA* can paralyze or “freeze” muscles. Currents more than 75 mA can cause a rapid, ineffective heartbeat, death will occur in a few minutes unless a defibrillator is used 75 mA is not much current – a small power drill uses 30 times as much Defibrillator in use * mA = milliamp ere = 1/1,000 of an ampere

14. Electrical Burns Most common shock-related, nonfatal injury Occurs when you touch live electrical wiring or equipment that is improperly used or maintained Typically occurs on the hands. Very serious injury that needs immediate attention

15. Falls Electric shock can also cause indirect injuries Workers in elevated locations who experience a shock may fall, resulting in serious injury or death

16. How is an electrical shock received? When two wires have different potential differences (voltages), current will flow if they are connected together. In most household wiring, the black wires are at zero volts because they are neutral. The red wires are at 220 volts ( For Single Phase relative to ground). If some one come into contact with an energized (live) red wire, and also in contact with the black neutral wire, current will pass through the body and WILL RECEIVE AN ELECTRIC SHOCK

17. FIRE There has been a series of fire incidents in many multistory buildings and industries in Pakistan. Results of these incidents at some of the places have been devastating, destroying whole building or industry. The most common cause of fire analyzed for these horrible incidents is short circuiting.

18. Electric Short Circuit Low-resistance path between a live wire and the ground, or between wires at different voltages) In a short circuit, current passes through the shorting material without passing through a load in the circuit, and the wire becomes overheated.

19. Reasons For Short Circuit There may be a number of reasons for electric short circuit; however, wiring with defects such as insulation failure, overloaded conductors and poor connections are found to play major role in this. Other fires are attributed to equipment such as electric motors, heaters, lighting and cooking appliances. The heat generated by loose connection can be sufficient to ignite flammable material, liquid or gas and hence may cause catastrophic fires and explosions.

20. Overload Conductor If too many devices are plugged into a circuit, the current will heat the wires to a very high temperature, which may cause a fire If the wire insulation melts, it can cause a fire in the area where the overload exists, even inside a wall

21. Electrical Hazards and How to Control Them Electrical accidents are caused by a combination of three factors: Unsafe equipment and/or installation, Workplaces made unsafe by the environment, and Unsafe work practices.

22. Hazard – Exposed Electrical Parts Cover removed from wiring or breaker box

23. Control – Isolate Electrical Parts Use guards or barriers Replace covers Guard live parts of electric equipment operating at 50 volts or more against accidental contact

24. Control – Isolate Electrical Parts - Cabinets, Boxes & Fittings Conductors going into them must be protected, and unused openings must be closed

25. Control – Close Openings Junction boxes, pull boxes and fittings must have approved covers Unused openings in cabinets, boxes and fittings must be closed Photo shows violations of these two requirements

26. Grounding Hazards Some of the most common violations Metal parts of an electrical wiring system that we touch (switch plates, ceiling light fixtures, conduit, etc.) should be at zero volts relative to ground Housings of motors, appliances or tools that are plugged into improperly grounded circuits may become energized If some one come into contact with an improperly grounded electrical device, CAN BESHOCKED

27. Safety Management System Since every process in an industry involves electricity, it is therefore not possible to prevent employees from electrical related incidents without implementing a proper safety management system. Job Hazard Analysis • A job hazard analysis, also called a job safety analysis is an organized approach that involves the worker and supervisor observing a task, breaking it down into steps. Each step is then analyzed for safety and operational needs.

28. DEFFINITIONS NEAR MISS: A Near miss describes incident where no property was damaged and no personal Injury sustained, but when a given a slight shift in time or position, damage and / or injury easily could have occurred.

29. DEFFINITIONS INCIDENT:An incident is an unplanned, un desired event that adversely affects the completion of a task ACCIDENT:National Safety Council defines an Accident as an undesired event that results in personal injury or property damage Incident/Accident Analysis • All non-injury incidents and injury accidents, even a minor electrical shock should be analyzed. Incidents analysis allows identifying and controlling hazards before they cause an injury.

30. Safe Working Practices Personnel involved in electrical work have often to deal with live working situations. It is therefore necessary to set such rules, which govern overall working activities. Only competent persons (who possess certificate,sufficient technical knowledge, experience and skill) should be given any task.

31. Proper Grounding of Equipments Grounding is connecting an electrical system to the earth with a wire. Excess or stray current travels through this wire to a grounding device (commonly called a “ground”) deep in the earth. Grounding prevents unwanted voltage on electrical components. Grounding creates a path for currents produced by unintended voltages on exposed parts. These currents follow the grounding path, rather than passing through the body of someone who touches the energized equipment.

32. Equipment needs to be grounded under any of these circumstances: The equipment is within 8 feet vertically and 5 feet horizontally of the floor or walking surface. The equipment is within 8 feet vertically and 5 feet horizontally of grounded metal objects you could touch. The equipment is located in a wet or damp area and is not isolated. The equipment is connected to a power supply by cord and plug and is not double-insulated.

33. Electrical Protective Devices These devices shut off electricity flow automatically in the event of an overload or ground-fault in the circuit Include fuses, circuit breakers, and ground-fault circuit-interrupters (GFCI’s). Fuses and circuit breakers are over current devices When there is too much current: Fuses melt Circuit breakers trip/ open

34. The NEC requires that GFCI’s be used in these high-risk situations: Electricity is used near water. The user of electrical equipment is grounded (by touching grounded material). Circuits are providing power to portable tools or outdoor receptacles. Temporary wiring or extension cords are used.

35. Grounding Path The path to ground from circuits, equipment, and enclosures must be permanent and continuous Violation shown here is an extension cord with a missing grounding prong

36. Hand-Held Electric Tools Hand-held electric tools pose a potential danger because they make continuous good contact with the hand To protect you from shock, burns, and electrocution, tools must: Have a three-wire cord with ground and be plugged into a grounded receptacle, or Be double insulated.

37. Guarding of Live Parts Must guard live parts of electric equipment operating at 50 volts or more against accidental contact by: Approved cabinets/enclosures, or Location or permanent partitions making them accessible only to qualified persons, or Elevation of 8 ft. or more above the floor or working surface Mark entrances to guarded locations with conspicuous warning signs

38. Guarding of Live Parts (cont’d) Must enclose or guard electric equipment in locations where it would be exposed to physical damage Violation shown here is physical damage to conduit

39. More vulnerable than fixed wiring Do not use if one of the recognized wiring methods can be used instead Flexible cords can be damaged by: Aging Door or window edges Staples or fastenings Abrasion from adjacent materials Activities in the area Improper use of flexible cords can cause shocks, burns or fire Use of Flexible Cords

40. Permissible Uses of Flexible CordsExamples Stationary equipment-to facilitate interchange Pendant, or Fixture Wiring Portable lamps, tools or appliances

41. Prohibited Uses of Flexible CordsExamples Substitute for fixed wiring Run through walls, ceilings, floors, doors, or windows

42. Tool Safety Tips Use gloves and appropriate footwear Store in dry place when not using Don’t use in wet/damp conditions Keep working areas well lit Ensure not a tripping hazard Don’t carry a tool by the cord Don’t yank the cord to disconnect it Keep cords away from heat, oil, & sharp edges Disconnect when not in use and when changing accessories such as blades & bits Remove damaged tools from use

43. Clues that Electrical Hazards Exist Tripped circuit breakers or blown fuses Warm tools, wires, cords, connections, or junction boxes GFCI that shuts off a circuit Worn or frayed insulation around wire or connection

44. Lockout and Tagging of Circuits Apply locks to power source after de-energizing Tag deactivated controls Tag de-energized equipment and circuits at all points where they can be energized Tags must identify equipment or circuits being worked on

45. Safety-Related Work Practices Use special insulated tools when working on fuses with energized terminals Don’t use worn or frayed cords and cables Don’t fasten extension cords with staples, hang from nails, or suspend by wire.

46. Preventing Electrical Hazards - Planning Plan your work with others Plan to avoid falls Plan to lock-out and tag-out equipment Remove jewelry/ rings Avoid wet conditions and overhead power lines

47. Avoid Wet Conditions If you touch a live wire or other electrical component while standing in even a small puddle of water you’ll get a shock. Damaged insulation, equipment, or tools can expose you to live electrical parts. Improperly grounded metal switch plates & ceiling lights are especially hazardous in wet conditions. Wet clothing and high humidity increase chances of being electrocuted.

48. Preventing Electrical Hazards - PPE Proper foot protection (not tennis shoes) Rubber insulating gloves, hoods, sleeves, matting, and blankets Hard hat (insulated - nonconductive) Face shield

49. Training Deenergize electric equipment before inspecting or repairing Using cords, cables, and electric tools that are in good condition Lockout / Tagout recognition and procedures Use appropriate protective equipment Train employees working with electric equipment in safe work practices, including: