Electrical (OSHA 10-Hour General Industry Outreach)

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1. Slide 1

   Electrical

   • OSHA 10-hour Outreach Training
   • General Industry
2. Slide 2

   Electrical

   • Source of photos: OSHA
3. Slide 3

   Introduction

   • Lesson objectives:
   • 1. Identify major electrical hazards
   • 2. Describe types of electrical hazards
   • 3. Describe electrical protection methods
   • 4. Recognize employer requirements to protect workers from electrical hazards
   • Source: OSHA
4. Slide 4

   Introduction

   • Definitions:
   • Electricity – movement
   • of the free electrons between atoms;
   • Related terms:
   • Current – the movement of electrical charge
   • Resistance – opposition to current flow
   • Voltage – a measurement of electrical force
   • Source: NIOSH
5. Slide 5

   Introduction

   • Conductors – substances, such as metals, that have little resistance to electricity
   • Insulators – substances, such as dry wood, rubber, glass and Bakelite, that have high resistance to electricity
   • Grounding – a conductive connection to the earth which acts as a protective measure
6. Slide 6

   Electrical Hazards

   • Serious injuries and death can be caused by electrical hazards such as arc flash, shocks, burns, falls, and fires. Source of graphics: OSHA
7. Slide 7

   Electrical Hazards

   • Examples of electrical hazards that could cause workers to be electrocuted.
   • https://www.osha.gov/video/shipyard_accidents/08_welder_electrocuted.ht ml
   • https://www.osha.gov/video/shipyard_accidents/15_lockout_tagout_failure.html
8. Slide 8

   Electrical Hazards

   • BE SAFE:
   • Burns
   • Electrocution
   • Shock
   • Arc flash/arc blast
   • Fire
   • Explosions
9. Slide 9

   Electrical Hazards

   • Burns:
   • Most common shock-related injury
   • Three types of electrical burns:
   • Electrical
   • Arc flash
   • Thermal contact
   • Source: OSHA
10. Slide 10

    Electrical Hazards

    • Electrocution:
    • Is fatal
    • Meaning: to kill with electrical shock
    • Results when a human is exposed to a lethal amount of electrical energy
11. Slide 11

    Electrical Hazards

    • Shock:
    • Body becomes part of electrical circuit
    • Reflex response to passage of electric current through the body
    • Source: OSHA
12. Slide 12

    Electrical Hazards

    • Arc Flash/Arc Blast
    • Arc flash
    • Sudden release of electrical energy through air when a high-voltage gap exists and there is a breakdown between conductors
    • Gives off thermal radiation (heat) and bright, intense light that can cause burns
    • Temperatures as high as 35,000°F
13. Slide 13

    Electrical Hazards

    • Arc blast – high-voltage arcs can also produce considerable pressure waves by rapidly heating the air and creating a blast
14. Slide 14

    Electrical Hazards

    • Fire:
    • Most result from problems with "fixed wiring”
    • Problems with cords, plugs, receptacles, and switches also cause electrical fires
15. Slide 15

    Electrical Hazards

    • Explosions:
    • Occur when electricity ignites explosive mixture of material in the air
    • Note:
    • Electricity is source of these hazards
    • All hazards are of equal importance
    • Lesson focuses on eliminating electrical hazards
16. Slide 16

    Electrical Hazards

    • Examples of fatal accidents:
    • Case #1: Worker electrocuted when the ladder came in contact with overhead power lines
    • Case #2: Worker electrocuted when mast came in contact with high voltage overhead lines
17. Slide 17

    Electrical Hazards

    • Case #3: Worker changing energized ballast on light fixture was electrocuted and fell to the concrete floor while working from an 8' fiberglass stepladder.
18. Slide 18

    Electrical Hazards

    • U.S. Bureau of Labor Statistics:
    • 156 electrocutions for 2014
    • Up from 141 in 2013
    • Source of graphics: OSHA
19. Slide 19

    Types of Electrical Hazards

    • Contact with overhead power lines:
    • Overhead and buried power lines carry extremely high voltage
    • Risks
    • Electrocution (main risk)
    • Burns and falls
    • Source: NIOSH
20. Slide 20

    Types of Electrical Hazards

    • Cranes are not the only equipment that can reach overhead power lines.
    • Use of ladders or suspension in a man-basket under or near power lines are risks.
    • Source: OSHA
21. Slide 21

    Types of Electrical Hazards

    • Important: the covering on an overhead power line is primarily for weather protection; therefore, workers need to know that if they touch a power line, covered or bare, death is probable.
    • https://www.osha.gov/dts/vtools/construction/ladder_powerline_fnl_eng_web.ht ml
22. Slide 22

    Types of Electrical Hazards

    • Contact with energized sources:
    • Live parts
    • The major hazards
    • Electrical shock and burns
    • Electrical shock occurs when the body becomes part of the electric circuit
    • Source: OSHA
23. Slide 23

    Types of Electrical Hazards

    • Severity and effects of an electrical shock depend on a number of factors
    • Pathway through the body
    • Amount of current
    • Length of time of the exposure
    • Whether skin is wet or dry
    • Water
    • Great conductor
    • Allows current to flow more easily in wet conditions and through wet skin
24. Slide 24

    Chart

    • (1,000 milliamperes = 1 amp; therefore, 15,000 milliamperes = 15 amp circuit)
    • Current
    • Reaction
    • Below 1 milliampere
    • Generally not perceptible
    • 1 milliampere
    • Faint tingle
    • 5 milliampere
    • Slight shock felt; not painful but disturbing. Average individual can let go. Strong involuntary reactions can lead to other injuries
    • 6-25 milliamperes (women)
    • Painful shock, loss of muscular control
    • 9-30 milliamperes (men)
    • The freezing current or “let-go” range. Individual cannot let go, but can be thrown away from the circuit if extensor muscles are stimulated.
    • 50-150 milliampres
    • Extreme pain, respiratory arrest, severe muscular contractions. Death is possible.
    • 1,000-4,300 milliamperes
    • Rhythmic pumping action of the heart ceases. Muscular contraction and nerve damage occur; death likely
    • 10,000 milliamperes
    • Cardiac arrest, severe burns; death probable
    • This table shows the body’s reaction when exposed to various levels of current. Source: OSHA
25. Slide 25

    Types of Electrical Hazards

    • Damaged or bare wires
    • Fault current may travel through a body, causing electrical burns or death, if
    • Power supply is not grounded
    • Path has been broken
    • There are live parts or bare wires
    • Extreme conditions and rough treatment can change electrical equipment from safe to hazardous
26. Slide 26

    Types of Electrical Hazards

    • Defective equipment or tools
    • These photos show examples of defective equipment/tools. Source of photos: OSHA
27. Slide 27

    Types of Electrical Hazards

    • Improper repairs
    • Examples of incidents
    • Ballast strap not replaced after repair = Electrocution of 11 year old boy
    • Cutting off bleed resistor on capacitor= causes 370-volt shock
    • Removing and leaving off terminal insulator on capacitor = causes 440-volt shock
28. Slide 28

    Types of Electrical Hazards

    • Improper use:
    • Extension and flexible cords
    • Care
    • Connection
    • Capacity
    • Source: TEEX SH 46F1-HT06
29. Slide 29

    Types of Electrical Hazards

    • Capacity affected by
    • Size of wire
    • 14 gauge = 15 amps
    • 12 gauge = 20 amps
    • Length of the cord
    • UL tag capacity
    • In general any cord over 100 ft. requires one size larger cord
    • (14 gauge to 12 gauge)
    • Source: OSHA
30. Slide 30

    Types of Electrical Hazards

    • Power strips:
    • Can be over loaded because of multiple plug arrangement
    • Most have overload protection but often malfunction causing fire
    • Use fixed wiring when possible
    • Source: UBATC
31. Slide 31

    Types of Electrical Hazards

    • Portable heaters and appliances:
    • Manufacturer recommendations not followed
    • Do not plug into a power strip! This causes overloads and fires.
    • Source of photos: UBATC
32. Slide 32

    Electrical Protection Methods

    • Maintain safe distance from overhead power lines:
    • Staying away
    • Following table shows the safe power line clearance distance for various line voltages.
    • https://youtu.be/Y2MwX738e1Y
    • Source of graphics: OSHA
33. Slide 33

    Electrical Protection Methods

    • Voltage
    • Minimum Clearance Distance
    • (nominal, kV, alternating current)
    • (feet)
    • Up to 50
    • Over 50 to 200
    • Over 200 to 350
    • Over 350 to 500
    • Over 500 to 750
    • Over 750 to 1000
    • Over 1000
    • (As established by the power line owner/operator or registered professional engineer who is a qualified person with respect to electrical transmission and distribution)
    • This table shows the minimum clearance distances, in feet, for different power line voltages. Source: OSHA
34. Slide 34

    Electrical Protection Methods

    • Use ground-fault circuit interrupters (GFCI):
    • Designed to protect people from electrical shock
    • Detects ground faults and interrupts electric current
    • Limits duration of electrical shock
    • Source: OSHA
35. Slide 35

    Electrical Protection Methods

    • Three types of GFCI:
    • Receptacle GFCI
    • Temporary/portable GFCI
    • Circuit Breaker GFCI
    • These photos show examples of the three types of GFCI. Source of photos: OSHA
36. Slide 36

    Electrical Protection Methods

    • Inspect portable tools and extension cords:
    • Workers need to inspect extension cords prior to their use for any cuts or abrasion.
    • Electric hand tools that are old, damaged, or misused may have damaged insulation inside.
37. Slide 37

    Electrical Protection Methods

    • Use power tools and equipment as designed:
    • Follow tool safety tips to avoid misusing equipment
    • Follow manufacturer’s instructions
38. Slide 38

    Electrical Protection Methods

    • Common examples of misused equipment
    • Source: TEEX SH 46F1-HT06
    • Source of photos: OSHA
    • These photos show examples of equipment misuse.
39. Slide 39

    Electrical Protection Methods

    • Tool safety tips
    • Never carry a tool by the cord.
    • Never yank the cord to disconnect it.
    • Keep cords away from heat, oil, and sharp edges.
    • Disconnect when not in use and when changing accessories such as blades and bits.
40. Slide 40

    Electrical Protection Methods

    • Avoid accidental starting. Do not hold fingers on the switch button while carrying a plugged-in tool.
    • Use gloves and appropriate footwear.
    • Store in dry a place when not using.
41. Slide 41

    Electrical Protection Methods

    • Don’t use in wet/damp environments.
    • Keep working areas well lit.
    • Ensure that cords do not cause a tripping hazard.
    • Remove damaged tools from use.
    • Use double-insulated tools.
42. Slide 42

    Electrical Protection Methods

    • Follow lockout/tagout (LOTO) procedures:
    • Lockout/tagout
    • Essential safety procedure
    • Protects workers from injury while working on or near electrical circuits and equipment
    • Prevents contact with operating equipment parts such as, blades, gears, shafts, etc.
    • Source: OSHA
43. Slide 43

    Electrical Protection Methods

    • LOTO prevents the unexpected release of hazardous gases, fluids, or solid matter in areas where workers are present.
    • Source of photos: OSHA
44. Slide 44

    Electrical Protection Methods

    • Power source identification:
    • Mark all breakers accordingly for the circuits they protect
    • Mark all disconnect means accordingly for the equipment they service
    • Identify all voltages with proper labeling
45. Slide 45

    Employer Requirements

    • Employer requirements to protect workers:
    • Ensure overhead power line safety
    • Isolate electrical parts
    • Supply ground-fault circuit interrupters (GFCI) protection
    • Establish and implement an AEGCP
    • Ensure power tools are maintained in a safe condition
46. Slide 46

    Employer Requirements

    • Ensure proper guarding
    • Provide training
    • Enforce LOTO safety related work practices
    • Ensure proper use of flexible cords and power strips
    • Ensure proper identification of power sources
47. Slide 47

    What’s Wrong?

    • Identify the hazards in these photos. Source of photos: TEEX SH 46F1-HT06
48. Slide 48

    What’s Wrong?

    • Identify the hazards in these photos. Source of photos: OSHA
49. Slide 49

    Knowledge Check

    • 1. What is electricity?
    • a. The movement of atoms within an object
    • b. The movement of free electrons between atoms
    • c. Solid mass
    • d. Movement within the nucleus of an atom
    • Answer: b. The movement of free electrons between atoms
50. Slide 50

    Knowledge Check

    • 2. “Electrocution” means ___.
    • a. received a mild electrical shock
    • b. killed by electrical shock
    • c. exposed to electrical current
    • d. any accident involving electricity
    • Answer: b. killed by electrical shock
    • R.I.P.
51. Slide 51

    Knowledge Check

    • 3. Arc flash/arc blast can reach maximum temperatures up to 350˚F?
    • a. True
    • b. False
    • Answer: b. False - temperatures can reach up to 3,500˚F
52. Slide 52

    Knowledge Check

    • 4. Which gauge of wire will carry the most current?
    • a. 14 gauge
    • b. 12 gauge
    • c. 10 gauge
    • d. 00 gauge
    • Answer: d. 00 gauge – the lower the wire gauge number, the more current it can carry
53. Slide 53

    Knowledge Check

    • 5. What does GFCI stand for?
    • a. Ground Flexible Conduit Insulator
    • b. Ground Flow Current Interceptor
    • c. Ground Fault Circuit Interrupter
    • d. Ground Floor Connection Intersector
    • Answer: c. Ground Fault Circuit Interrupter
54. Slide 54

    Knowledge Check

    • 6. Which of the following is a safe practice?
    • a. Carrying power tool by the cord
    • b. Holding fingers on switch button while carrying a plugged-in tool
    • c. Keeping cords away from heat, oil, and sharp edges
    • d. Yanking cord to disconnect plug from outlet
    • Answer: c. Keeping cords away from heat, oil, and sharp edges
55. Slide 55

    Knowledge Check

    • 7. Who is responsible for ensuring that overhead power lines are de-energized?
    • a. Power company
    • b. Employer
    • c. Employee
    • d. Municipality
    • Answer: b. Employer