Electrical Hazards and Arc Flash Awareness Training

1. Electrical Hazards and Arc Flash
Awareness
Instructor: Brian Terry

2. Class Outline
• Welcome/Overview
• Accident Statistics
• Electrical Terminology
• Introduction to Electrical Hazards
– Electrical Shock / Electrocution
– Electrical Burns
– Arc Flash
– Arc Blast
• Industry Standards
• Arc Hazard Analysis

3. Class Outline
• Arc Hazard Boundary
• Four Approach Boundaries
– Limited Approach Boundary
– Restricted Approach Boundary
– Prohibited Approach Boundary
– Flash Protection Approach Boundary
• Qualified and Unqualified Persons
• Energized Electrical Work Permit
• Arc Flash Hazard Marking Requirements

4. Class Outline
• Hazard Risk Categories
• PPE / FR Clothing
• Safe Work Practices
• Identifying Other Electrical Hazards
– Inadequate Wiring Hazards
– Overload Hazards
– Grounding Hazards
– Identifying Disconnects
– Clear Spaces
– Ground Paths
– Guarding Live Parts
– Clues that Electrical Hazards Exist

5. Accident Statistics

6. National Safety Council Statistics
• 30,000 electrical shock accidents occur
each year.
• 1,000 fatalities due to electrocution occur
each year.
• 5 to 10 arc flash explosions occur in
electrical equipment every day.
• 2,000 workers are sent to burn centers with
severe injuries each year.

7. Electrical Injuries
• In 2010 –
– 1,537,600 All industries, all occupations
– 3,394 persons injured from contact w/current
– 2,000 injured from electrical burns
• From 1992 – 2001 (9 year period)
– 44, 363 injuries
– 27,262 from shock
– 17,101 from arc flash burns

12. Introduction to Electrical
Hazards

13. Hazards of electricity
• There are five main types of electrical
injuries:
– Electrical shock
– Electrocution (death due to electrical shock)
– Electrical Burns
– Arc Flash
– Arc Blast

14. 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
• LOW VOLTAGE DOES NOT
MEAN LOW HAZARD

15. Dangers of Electrical Shock
• Currents greater than 75 mA* can cause
ventricular fibrillation (rapid, ineffective
heartbeat)
• Will cause death in a few minutes unless a
defibrillator is used
• 75 mA is not much current – a small power
drill uses 30 times as much
* mA = milliampere = 1/1,000 of an ampere

16. How is an electrical shock received?
• When two wires have different potential
differences (voltages), current will flow if they are
connected together
• If you come into contact with an energized (live)
wire, and you are also in contact with a Neutral,
grounded wire, a conductor with a different phase
voltage, current will pass through your body and
YOU WILL RECEIVE A SHOCK

17. How is an electrical shock received?
• If you are in contact with an energized wire or any
energized electrical component, and also with any
grounded object, YOU WILL RECEIVE A
SHOCK!
• You can even receive a shock when you are not in
contact with a ground
– If you contact both wires of a 240-volt cable, YOU
WILL RECEIVE A SHOCK and possibly be
electrocuted

18. Electrocution
• Accidental death by
electric shock.
• An average of one
worker is electrocuted
on the job every day.
• NSCS states that
1,000 fatalities due to
electrocution occur
each year.

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

20. Arc Flash
• Arc flash occurs when an electrical current
passes through air.
• It creates temperatures up to 30,000 o
F
• It burns skin and ignites clothing causing
additional burns.
• It can create an explosion
• It can create dangerous vapors

21. Arc Blast
• Arc blast occur when the extreme
temperatures of the electrical arc cause
explosive expansion of both the
surrounding air and the metal in the arc’s
path.
• It creates extremely high air pressure
• A very loud sound
• The force sends flying shrapnel and molten
metal in a 270o
outward radius.

22. What happens during an Arc Flash /Blast?
• An Arc Flash is the result of a rapid release of
energy due to an arcing fault between a phase bus
bar and another phase bus bar, Neutral or a Ground.
• During an arc fault, The ionized air is the conductor.
• After the short burns away, the arc fault is then
sustained by the establishment of highly conductive
plasma.
• This massive energy discharge burns the bus bars,
vaporizing the copper, expanding rapidly into an
explosive volume of approximately 40,000 to 1.
• This explosion devastates everything in its path,
creating deadly shrapnel as it dissipates.

23. Laboratory Controlled Arc BlastLaboratory Controlled Arc BlastLaboratory Controlled Arc BlastLaboratory Controlled Arc Blast

24. Arc Fault
A BA B
Short Circuit

25. Electrical Arc Flash
Pressure Waves
Copper Vapor:
Solid to Vapor
Expands by
67,000 times
Molten Metal
Intense Light
Hot Air-Rapid Expansion
35,000 °F
Shrapnell
Sound Waves

33. > Indicates Meter Pegged
Results
SoundSoundSoundSound
141.5 db @ 2 ft.
T2
>225°C / 437°F
T3
50°C / 122°F
P1
>2160 lbs/sq.ft
> 225°C / 437°F
T1

34. What about Circuit Protection?
• The arc fault current is usually much less
than the available bolted fault current and
below the rating of circuit breakers.
• Unless these devices have been selected to
handle the arc fault condition, they will
NOT trip and the full force of an arc flash
will occur.

35. Are there any circuit protection devices
that can suppress fault currents during
arc flash conditions?
• The answer is Yes!, some companies incorporate
transformers and other arc fault suppression
devices in there circuit breakers that limit the
amount of fault current available during an Arc
flash condition.
• These are being developed and may be available
for certain applications.
• But by NO means, this takes the complete arc
flash hazard away.

36. Why focus on Arc Flash?
• In the early 1980’s Ralph Lee published a
paper in the IEEE Transactions on
Industrial Applications, titled“ The Other
Electrical Hazard: Electric Arc Blast Burns”
• The effect of this paper caused industry to
realize that protection was needed against
this electrical hazard and four industry
standards were developed.

37. Industry Standards

38. Industry Standards for arc flash
prevention
• OSHA 29 Code of Federal Regulations
(CFR) part 1910 Subpart S
• NFPA 70 National Electrical Code
• NFPA 70E Standard for Electrical Safety
Requirements for Employee Workplaces.
• IEEE Standard 1584 Guide for Performing
Arc Flash Hazard Calculations.

39. Compliance with OSHA involves
adherence to a six-point plan:
• 1. A facility must provide, and be able to demonstrate,
a safety program with defined responsibilities.
• 2. Calculations for the degree of Arc Flash Hazard.
• 3. Correct personal protective equipment (PPE) for
workers.
• 4.Training for workers on the hazards of Arc Flash.
• 5. Appropriate tools for safe working.
• 6. Warning labels on equipment. (provided by the
owner of the equipment, Not manufacturers)

40. OSHA 29CFR1910.335 (a) (1)
• (i) Employees working in areas where there
are potential electrical hazards shall be
provided with, and shall use, electrical
protective equipment that is appropriate for
the specific parts of the body to be
protected and for the work to be performed.

41. • Requirements for safe work practices
• Addresses hazards:
– Shock
– Arc Flash
• Requirements for
shock and arc flash
boundaries
• Requirements
personal protective
equipment
NFPA 70E Standard for Electrical Safety

42. NFPA 70A Layout

43. Mitigation of Electrical Hazards
• What do you thinks is the best practices to use when
managing the electrical hazards in your workplace?
• Knowing your environment and being aware of your
surroundings
• Know the electrical system and associated hazards
• Be mindful of your coworkers and their locations
• Use proper PPE for the conditions and equipment
• Know the proper procedures for installations and
maintenance of equipment

44. Qualified vs Unqualified
• Qualified Person. A qualified person shall be trained
and knowledgeable of the construction and operation of
equipment or a specific work method and be trained to
recognize and avoid the electrical hazards that might be
present with respect to that equipment or work method.
• One who has skills and knowledge related to the
construction and operation of the electrical equipment
and installations and has received safety training to
recognize and avoid the hazards involved.
• A person can be considered qualified with respect to
certain equipment and methods but still be unqualified
for others.

45. Qualified vs Unqualified
• Unqualified Persons. Unqualified persons
shall be trained in, and be familiar with, any
electrical safety related practices necessary
for their safety.
• A person who is not a qualified person.

46. Why a Safety Program
• Safer work environment
• Personnel Safety
• Fewer work related injuries
• Fewer days missed due to work injuries
• Lower insurance rates
• Fewer medical cost to employee and employer
• A more confident workforce
• The saving of lives of qualified and unqualified
personnel

47. Identifying Electrical Hazards
• Electrical Hazard. A dangerous condition
such that contact or equipment failure can
result in electric shock, arc flash burn,
thermal burn, or blast.
• Three Types of Electrical Hazards
• Electrical Shock
• Arc-flash or Arc-blast
• Secondary Injury

48. Shock Hazard
• Shock Hazard. A dangerous condition associated
with the possible release of energy caused by
contact or approach to energized electrical
conductors or circuit parts.
Shock: Sudden stimulation of nerves and
contractions of muscles caused by the discharge of
electricity through the body.
Most electrical fatalities are caused by shock not
arc flash

49. Arc Flash Hazard
• Arc Flash Hazard. A dangerous condition
associated with the possible release of energy
caused by an electric arc.
• Arc Flash Hazard Analysis. A study
investigating a worker’s potential exposure to arc
flash energy, conducted for the purpose of injury
prevention and the determination of safe work
practices, arc flash boundary, and the appropriate
levels of personal protective equipment (PPE).

50. Secondary Injury Hazards
• Burns and Ignition
• Falls resulting from shock or arc flash
• Smoke inhalation
• Risk of personnel during a confined space
rescue

51. Hazard Video
• http://www.youtube.com/watch?
v=4bBvmPRqfmo

52. Safety Related Work Practices
• What is an Electrically Safe Work
Condition?
• A state in which an electrical conductor or
circuit part has been disconnected from
energized parts, locked/tagged in
accordance with established standards,
tested to ensure the absence of voltage, and
grounded if determined necessary.

53. Step to Insure an Elec. Safe Condition
• DISCONNECT THE ELECTRICITY FROM
THE CIRCUIT
• LOCK-OUT / TAG-OUT PLACED ON THE
DISCONNECT
• TEST THE CIRCUIT TO INSURE ALL POWER
HAS BEEN REMOVED
• ADD AN ADITIONAL SAFETY GROUND IF
YOU FEEL IT IS NESSESARY

54. Two Types of Lockout/tagout
• Simple
• All lockout/tagout procedures that involve only a
qualified person(s) de-energizing one set of
conductors or circuit part source for the sole
purpose of safeguarding employees from exposure
to electrical hazards shall be considered to be a
simple lockout/tagout. Simple lockout/tagout plans
shall not be required to be written for each
application. Each worker shall be responsible for his
or her own lockout/tagout.

55. Two Types of Lockout/tagout
• Complex
• A complex lockout/tagout plan shall be permitted where one or
more of the following exist:
• (1) Multiple energy sources
• (2) Multiple crews
• (3) Multiple crafts
• (4) Multiple locations
• (5) Multiple employers
• (6) Multiple disconnecting means
• (7) Particular sequences
• (8) Job or task that continues for more than one work period

56. Two Types of Lockout/tagout
• (b) All complex lockout/tagout procedures shall
require a written plan of execution that identifies the
person in charge.
• (c) The complex lockout/tagout procedure shall vest
primary responsibility in an authorized employee
for a set number of employees working under the
protection of a group lockout or tagout device (such
as an operation lock). The person in charge shall be
held accountable for safe execution of the complex
lockout/tagout.

57. Approach Boundaries to Energized
Electrical Conductors or Circuit Parts

58. Approach Boundaries to Energized
Electrical Conductors or Circuit Parts

59. Approach Boundaries to Energized
Electrical Conductors or Circuit Parts

60. Arc Hazard Analysis

61. Heat Energy
• Incident Energy level
– Measured in (Cal/cm2
) –(Calories per square
centimeter)
– Determined by Arc Hazard Analysis
• Exposure to 1.2 Cal/cm2
for 1/10 sec,
unproductive skin reaches a temperature of
176o
F (80o
C). This is the onset of second
degree burns.

62. Bus Report
Bus Name Protective Bus Bus Prot Dev Prot Dev Trip/ Breaker Ground Equip Gap Arc Flash Working Incident Required Protec
Device kV Bolted Bolted Arcing Delay Opening System Type Boundary Distance Energy FR Clothing
Name Fault Fault Fault Time Time (in) (in) (cal/cm2) Class
(kA) (kA) (kA) (sec.) (sec.)
11USS13.8kV LD 11USS HVFU 13.8 18.08 17.91 17.21 0.01 0 No SWG 153 9 36 0.30 Class 0
11USS13.8kV LN SR750 11USS 13.8 18.08 17.91 17.21 0.016 0.083 No SWG 153 92 36 2.97 Class 1
12USS13.8kV LD 12USS HVFU 13.8 22.79 21.55 17.53 0.08 0 No SWG 153 80 36 2.60 Class 1 (*3)
12USS13.8kV LN SR750 12USS 13.8 22.79 21.55 20.63 0.02 0.083 No SWG 153 122 36 3.91 Class 1
13USS 103B LD 13USS 103B 0.48 60.56 57.65 26.87 0.05 0 No SWG 32 56 24 4.20 Class 2
13USS 103C LD 13USS 103C 0.48 60.56 57.65 26.87 0.05 0 No SWG 32 56 24 4.20 Class 2
13USS 103D LD 13USS 103D 0.48 60.56 57.65 26.87 0.05 0 No SWG 32 56 24 4.20 Class 2
13USS 104B LD 13USS 104B 0.48 60.56 57.65 26.87 0.05 0 No SWG 32 56 24 4.20 Class 2
13USS 104C LD 13USS 104C 0.48 60.56 57.65 26.87 0.05 0 No SWG 32 56 24 4.20 Class 2
13USS 13.8kVLD 13USS HVFU 13.8 19.25 18.86 18.1 0.01 0 No SWG 153 9 36 0.32 Class 0
13USS 13.8kVLN SR750 13USS 13.8 19.25 18.86 18.1 0.016 0.083 No SWG 153 97 36 3.15 Class 1
13USS 480V BUS 13USS MAIN 0.48 60.56 45.99 18.22 0.652 0 No SWG 32 246 24 36.8 Class 4 (*3)
13USS MAIN LN 13USS HVFU 0.48 60.56 45.99 21.44 2 0 No SWG 32 583 24 131 Dangerous!!!

63. Arc Hazard Boundary
• The distance from arc where unprotected
persons would only be exposed to
temperatures that is limited to the onset of a
second degree burn.
• Only qualified persons wearing the proper
PPE may cross this boundary.

64. Four Approach Boundaries
• Flash Protection Boundary
• Limited Approach Boundary
• Restricted Approach Boundary
• Prohibited Approach Boundary

65. Approach Boundaries – NFPA 70E

66. Limited Approach Boundary
• Unqualified persons must stay a safe distance called
the Limited Approach Boundary.
– 3.5 ft. for fixed circuit parts ( 50 to 750 volts)
– 10 ft. for exposed movable conductors ( 50 to 750 volts)
– Boundaries increase as voltage gets higher to more than
23 ft in some cases.

67. Restricted Approach Boundary
• Access limited to qualified persons.
• Increased risk of shock due to arc-over combine
with inadvertent movement.
• Requirements include shock protection
techniques, careful movement, an approved
written work plan an appropriate PPE.
• Restricted approach limits are one foot at 301V to
750 V, and increase quickly to 15 feet at higher
voltages.

68. Prohibited Approach Boundary
• Crossing this is considered the same as touching the live
part.
• Work is limited to qualified persons, only when absolutely
necessary.
• Documented plan needed to explain why you must work
that close.
• Plan must include a risk analysis and have management
approval.
• Requires appropriate PPE.
• Prohibited approach boundaries range from one inch at 301
V to 750 V level, to 14 feet, 5inches at 75 to 800 kilovolts.

69. Setting The Flash Protection
Boundary
• Flash Protection Boundary
– Distance from exposed, energized conductor that would
cause incident energy of 1.2 cal/cm2
• 1.0 cal/cm2
is amount of heat produce by a match on finger tip
for 1 second
– If Boundary is crossed, must wear flash protective
equipment.
• In most systems 600 V or less the boundary is 4
feet.
• The Flash Protection is listed on the Energized
Electrical Work Permit.

70. ELECTRICAL HAZARD BOUNDARIES
Note: shock boundaries dependent on system voltage level

71. Qualified and Unqualified Persons
• Personnel are divided into two groups,
qualified and unqualified for safety
purposes.
• Qualified means: that you have the training
and knowledge to do the task safely.
• Unqualified means: you do not

72. An Unqualified Person
• Never performs Lockout/Tagout.
• Never works with energized equipment.
• Never enter high-risk areas.
• Never comes too close to certain hazardous
equipment.

73. A Qualified Person
• Knows how to use special precautionary
techniques.
• Knows how to use Personal Protective Equipment.
• Knows how to use Arc Flash insulating and
shielding equipment.
• Knows how to use insulated tools and test
equipment.
• Knows how to work on or near exposed live parts
50 volts and above.

74. A Qualified Person
• Knows how to tell exposed energized parts from
others.
• Has learn the nominal voltage of exposed live
parts.
• Knows the safe approach distances for various
voltages.
• Be able to Identify hazards of the task, the PPE
you will need and job planning necessary to work
safety.

75. Minimum Required Labeling

77. WARNING!
Arc Flash and Shock Hazard
Appropriate PPE Required
24 inch Flash Hazard Boundary
3 cal/cm2 Flash Hazard at 18 inches
480 VAC Shock Hazard when Cover is removed
42 inch Limited Approach
12 inch Restricted Approach - 500 V Class 00 Gloves
1 inch Prohibited Approach - 500 V Class 00 Gloves
Date: 6/28/2001
Bldg. ECR #1 Equipment Name: Slurry Pump Starter
WARNING!
Arc Flash and Shock Hazard
Appropriate PPE Required
24 inch Flash Hazard Boundary
3 cal/cm2 Flash Hazard at 18 inches
480 VAC Shock Hazard when Cover is removed
42 inch Limited Approach
12 inch Restricted Approach - 500 V Class 00 Gloves
1 inch Prohibited Approach - 500 V Class 00 Gloves
Date: 6/28/2001
Bldg. ECR #1 Equipment Name: Slurry Pump Starter

78. 24 inch Flash Hazard Boundary
3 cal/cm•2 Flash Hazard at 18 inches
1DF PPE Level, 1 Layer 6 oz Nomex ®,
Leather Gloves Faceshield
480 VAC Shock Hazard when Cover is removed
36 inch Limited Approach
12 inch Restricted Approach - 500 V Class 00 Gloves
1 inch Prohibited Approach - 500 V Class 00 Gloves
Equipment Name:Slurry Pump Starter
WARNING!
Arc Flash and Shock Hazard
Appropriate PPE Required
Courtesy E.I. du Pont de Nemours & Co.

79. Hazard / Risk Category
Classifications

80. Hazard Risk Categories
• List the Minimum requirements based on Potential
Incident Energy Levels determined by Arc Hazard
Analysis.
• The Hazard Risk Categories range from 0 through 4.
• Hazard Risk Category 4 is the most dangerous
having the greatest risk due to the magnitude of the
Potential Incident Energy Levels involved.

81. Hazard Category Zero
• Long sleeve shirt and long pants made from
non-melting natural fiber, 100% cotton or
100% wool.
– This provides no protection from heat energy,
but will not melt into the skin.
• Non-conductive safety eyewear.
• Example: Reading a door mounted meter
while the panel door remains closed.

82. Hazard Category One
• Clothing with a minimum Arc Rating: 4 Cal/cm2
• 100% cotton Jeans min weight (12 oz/yd2
) or FR
rated pants.
• FR rated Shirt or FR rated coveralls.
• Electrically rated Hard Hat.
• Non-conductive safety eyewear.
• Example: Removing bolted cover to expose live
parts on panel boards rated 240V and below.

83. Hazard Category Two
• Clothing with a minimum Arc Rating: 8 Cal/cm2
• Under layer of 100% non-melting natural fiber
(cotton/wool).
• FR rated shirt / pants or coveralls.
• FR rated Face shield or flash suit hood.
• Electrically rated Hard Hat, Eye protection, Boots and
gloves.
• Example: Performing diagnostic testing or voltage
measurements on 600V switchgear.

84. Hazard Category Three
• Clothing with a minimum Arc Rating: 25 Cal/cm2
• Two Under layers of 100% non-melting natural fiber
(cotton/wool) rated at 15 Cal/cm2
which will give a
combine protection of 30 Cal/cm2
or a multi-layer flash
suit rated at 40 Cal/cm2
.
• FR rated flash suit hood.
• Electrically rated Hard Hat.
• Eye protection.
• Boots with dielectric overshoes.
• Electrically insulated FR rated gloves.
• And hearing protection for exposure to 200 dB or better.

85. Hazard Category Four
• Clothing with a minimum Arc Rating: 40 Cal/cm2
• 40 Cal/cm2
Flash suit.
• FR rated flash suit hood.
• Electrically rated Hard Hat.
• Eye protection.
• Boots with dielectric overshoes.
• Electrically insulated FR rated gloves.
• And hearing protection for exposure to 200 dB or
better.

86. So, What Do I Do If I’m
(Way) Above 40 cal/cm2

87. Solutions
• Above 40 cal/cm2
– Label equipment warning that no PPE is available
– Refer to safety procedures
– Must use engineered solution
• Current limiting fuses
• Arc Resistant switchgear
• Remote racking
• Remote operation through Smart Equipment
• Zone Interlocking
• IP20 shrouding
• Re-coordinating protective devices
• Increasing distance
• Enabling instantaneous function
• De-energizing before operation

90. Prohibited Clothing
• Polyester
• Nylon
• Rayon
• Any blend of the above fabrics
• Any metallic or conductive clothing.
• Metal/ Plastic Jewelry

91. Personal Protective Equipment
(PPE)
• Anytime your body crosses the Restrictive
Approach Boundary or the Flash Protection
Boundary, You Must wear PPE to protect
you from Arc Flash and Electrical Shock.

92. Depending on the task, you may need:
• Rubber insulated gloves and insulated tools to protect
against electrical shock.
• Leather hand and arm covers ro protect against arc flash
burns and flying debris.
• Head, face, neck, chin, eye and body protection.
• Hearing protection
• Dielectric overshoes
• A full multi-layer flash suit, including hood, face shield and
suplied air may be needed for higher risk.

93. Category One Clothing
5 Cal/cm2

94. Category Two Clothing
11 Cal/cm2
kit

95. Category Three Clothing
25 Cal/cm2

96. Category Four Clothing
40 Cal/cm2

97. 100 Cal/cm2
FR rated Clothing

100. Safe Work Practices

101. Safe work Practices
• Remove conductive articles.
• Wear natural fibers (100% cotton/100%
wool).
• Clothing should be loose-fitting and FR
rated.
• Wear eye protection – safety glasses or
goggles under Face shields or hoods.
• Get an Energized Electrical Work Permit.

102. Safe work Practices
• Double check tools and equipment voltage
ratings.
• Keep tools and equipment from accidentally
coming in contact with live parts.
• All parts are considered Live until you test
to make sure.
• Work in adequate lighting.

103. Safe work Practices
• Never reach blindly into equipment.
• Never be put into a position where you could fall
into live parts.
• Keep vehicles and mechanical equipment 10 feet
from energized overhead lines.
• Do not touch Vehicles that could accidentally
become energized without proper PPE.

104. Safe work Practices
• Keep unqualified persons out of the area
beyond the Limited Approach Boundary.
• Use attendants to keep unqualified people
out of the area.
• Attendants may be needed to observe the
qualified worker for safety reasons.

105. Identifying Other Electrical
Hazards

106. Clear Spaces
• Must have access to
working space around
electrical equipment.
• Must have at least 3’ in
front of switch boards
or motor control centers

107. Grounding Path
• The path to ground from circuits,
equipment, and enclosures must be
permanent and continuous

108. 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

109. 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

110. Fuses and Circuit Breakers
• Molded-Case Circuit Breakers.
• Molded-case circuit breakers shall be
maintained free of cracks in cases and
cracked or broken operating handles.

111. Fuses and Circuit Breakers
• Circuit Breaker Testing After Electrical
Faults. Circuit breakers that interrupt faults
approaching their interrupting ratings shall
be inspected and tested in accordance with
the manufacturer’s instructions.

112. Rotating Equipment
• Guards, Barriers, and Access Plates.
Guards, barriers, and access plates shall be
maintained to prevent employees from
contacting moving or energized parts.

113. Portable Elect Tools and Equip
• 245.1 Maintenance Requirements for
Portable Electric Tools and Equipment.
Attachment plugs, receptacles, cover plates,
and cord connectors shall be maintained
such that the following criteria are met:

114. Portable Elect Tools and Equip
• (1) There are no breaks, damage, or cracks
exposing energized conductors and circuit
parts.
• (2) There are no missing cover plates.
• (3) Terminations have no stray strands or loose
terminals.
• (4) There are no missing, loose, altered, or
damaged blades, pins, or contacts.
• (5) Polarity is correct.

115. Personal Safety and Protective
Equipment
• 250.2 Inspection and Testing of Protective
Equipment and Protective Tools.
• (A) Visual. Safety and protective equipment and
protective tools shall be visually inspected for
damage and defects.
• (B) Testing. The insulation of protective
equipment and protective tools, shall be verified
by the appropriate test.

116. Personal Safety and Protective
Equipment
• 250.3 Safety Grounding Equipment.
• (A) Visual. Personal protective ground cable sets
shall be inspected for cuts in the protective sheath
and damage to the conductors. Clamps and
connector strain relief devices shall be checked for
tightness.
• (B) Testing. Prior to being returned to service,
temporary protective grounding equipment that
has been repaired or modified shall be tested.

117. Conclusion
• Arc Flash Awareness is an important part of any
electrical workers training.
• The standards used are to protect qualified
electrical workers and the Unqualified.
• Proper PPE should always be used for the Hazard
Category established for the equipment.
• Safe work practices should always be followed on
and off the Job… Your life may depend upon it.

118. Quiz
• True False 1. Electric shock is the most frequent
cause of electrical injury and death.
• True False 2. Arc Flash temperatures never get
higher that 2,000 degrees Fahrenheit.
• True False 3. An Arc blast can burst your eardrums
and harm your hearing.
• True False 4. A job briefing is designed to help
you get the job done quickly and
correctly.

119. Quiz
• True False 5. Equipment in an electrically
safe work condition is not,
and cannot be energized.
• True False 6. A written permit is required
any time live parts over 300
volts are not placed in an
electrically safe work
condition.

120. Quiz
• True False 7. The energized electrical
work permit list practices,
procedures, and equipment
needed to protect employees
from arc flash and from
contact with live parts.

121. Quiz
• True False 8. The results of the hazard
analyses for shock and for
arc flash are listed on the
energized electrical work
permit.

122. Quiz
• True False 9. The Limited Approach
Boundary for voltages
between 50 and 750 volts is
3.5 feet for fixed circuit parts
and 10 feet for exposed
movable conductors.

123. Quiz
• True False 10. Unqualified personnel must
stay inside the Limited
Approach Boundary.
• True False 11. Crossing the Prohibited
Approach Boundary is
considered the same as
touching the live part.

124. Quiz
• True False 12. An arc flash can burn skin
and clothes, damage hearing,
and knock you off your feet
… or ladder.
• True False 13. A Flash Hazard Analysis
predicts the risk of an arc
flash occurring and set a
Flash Protection Boundary.

125. Quiz
• True False 14. In most of 600 volts or less,
the Flash Protection Boundary
is 15 feet. ( it is 4 Feet)
• True False 15. Any time any part of your
body crosses either the Restricted
Approach Boundary or Flash
Protection Boundary, you must
wear PPE to protect you from arc
flash and shock.

126. Quiz
• True False 16. Your employer may use NFPA
guidelines to determine the correct
PPE needed for a specific job.
• True False 17. The PPE you need for a specific
job is listed on the Flash Hazard
Analysis. (PPE is listed on the
Energized Electrical Work Permit)
• True False 18. You may use PPE contaminated
with grease or oil as long as you
clean it as soon as possible.

127. Quiz
• True False 19. You should wear synthetic
fibers next to you skin
because it does not melt and
stick like cotton does.
• True False 20. In some cases you will need
to wear Flame-resistant
clothing even when you wear
a full flash suit.

128. Arc Flash Video
• https://www.youtube.com/watch?
v=hfnEuRA7-vo

129. End of Lecture