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Electrical Safe Work Practices


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Title: Electrical Safe Work Practices

Electrical Safe Work Practices
A Four Hour Training Program for Workers in
General Industry
Course Objectives
Following this four hour course, participants
should understand
  • Background information regarding Electrical Safe
    Work Practices
  • How to protect against electrical hazards
  • What an arc blast is
  • Fundamentals of Electricity

5. Definition of a qualified person vs. an
unqualified person 6. Electrical hazard victim
first aid 7. Lockout/Tagout familiarization 8.
How to select the appropriate PPE
(No Transcript)
  • Draws heavily from the 2000 edition of the
    National Fire Protection Association's (NFPA)
    Electrical Safety Requirements for Employee
    Workplaces (NFPA 70E), and
  • The 2002 edition of the National Electrical Code

The Electrical Installation Standard
  • Focuses on safety in the design and installation
    of electric equipment in the workplace
  • Will provide the first update of the installation
    requirements in the general industry electrical
    installation standard since 1981
  • This final rule became effective on August 13,

Why Change Now?
  • The original standard was based on a 1979
    national consensus standard the 1979 edition of
    Part I of NFPA 70E
  • NFPA 70E has been updated on several occasions
  • The primary objective of the Subpart S revision
    was to update the standard to recognize, and in
    some cases require, more current electrical
    safety technology.

  • Hazards Associated With Electricity
  • Nature of Electrical Accidents
  • Protective Measures
  • Significant Risk and Reduction in Risk

Hazards Associated with Electricity
Hazards Associated With Electricity
  • Electricity is widely recognized as a serious
    workplace hazard, exposing employees to electric
    shock, burns, fires, and explosions. According to
    the Bureau of Labor Statistics, 247 employees
    were killed by contact with electrical current in
    2006. Other employees have been killed or
    injured in fires and explosions caused by

Hazards Associated With Electricity
  • Electrical Shock
  • Arc-Flash Burns
  • Arc-Blast
  • Secondary hazards include
  • Falls
  • Fire

It is well known that the human body will conduct
Each Year
  • Many employees suffer pain or injuries from
    electric shocks or death from electrocution
  • Current through the body, even at levels as low
    as 3 milliamperes, can also cause injuries of an
    indirect or secondary nature
  • involuntary muscular reaction from the electric
  • bruises, bone fractures and even death resulting
    from collisions or falls

Electrical Hazard Summary
  • Shock
  • Arc-Flash
  • Heat
  • Fire
  • Arc-Blast
  • Pressure
  • Shrapnel
  • Sound

Youth Worker Implications
The National Institute for Occupational Safety
and Health (NIOSH) estimates that 200,000 young
workers under the age of 18 suffer work-related
injuries in the United States each year.
  • Publication No. 2002-123
  • PDF is on the CD in your
  • packet

  • Electrocution is the third leading cause of
    work-related deaths among 16- and 17-year-olds,
    after motor vehicle deaths and workplace homicide
  • Electrocution is the cause of 12 of all
    workplace deaths among young workers

  • NIOSH recommends that actual employment in the
    electrical trades be delayed until individuals
    reach the age of 18.

  • Three basic types
  • -- electrical burns
  • -- arc burns, and
  • -- thermal contact burns
  • All three types of burns may be produced

Electrical Burns
  • are the result of the electric current flowing in
    the tissues
  • may be skin deep, or
  • may affect deeper layers (such as muscles and
    bones - or both)
  • tissue damage results from the bodys inability
    to cool
  • typically these are slow to heal

Arc Burns
  • are the result of high temperatures produced by
    electric arcs or by explosions close to the body

Thermal Contact Burns
  • Are normally experienced from the skin contacting
    hot surfaces of overheated electric conductors,
    conduits, or other energized equipment
  • This is a contact injury to the hand
  • Photograph by Timothy G. Price, MD.

Typical Burn Locations
  • Burns are usually most severe at the points of
    contact with the electrical source and the
    ground. The hands, heels, and head are common
    points of contact
  • Electric shock injury to the hand. Photograph
    courtesy of William Smock, MD

Subsequent Effects to the Body
  • Burn wound cellulitis causes swelling and pain
    in the uninjured skin around the periphery of the
  • Invasive burn wound infection implies that
    bacteria or fungi in the burn area are invading
    the underlying tissues. Wounds display a change
    in color, new drainage, and, commonly, a foul
    odor. This infection can be life threatening.

Subsequent Effects to the Body
  • If hand positioning and therapy are ignored
    while overlying burns heal, long-term suboptimal
    function may result.

Electrocution Injury
  • This man accidentally grabbed a high voltage
    electrical line, producing the entrance wound
    injury seen on the palm of the hand, with
    subsequent soft tissue damage and swelling
    extending to the forearm.
  • Below on the dorsum of the hand can be seen the
    wounds produced as the current exited the hand.

Arc Flash
  • An Arc Flash is an explosive release of energy
    caused by an electrical arc due to either a phase
    to ground or phase to phase fault. This fault can
    be caused by many different factors including
    accidental contact with electrical systems, build
    up of conductive dust, corrosion, dropped tools,
    and improper work procedures

Arc Flash
  • If the current involved is great enough,
    electric arcs can start a fire. Fires can also be
    created by overheating equipment or by conductors
    carrying too much current.
  • Power Plant Substation Explodes Video
  • (click on hyperlink to view)

Arc Flash
  • Electrical Arc Flash lasts a fraction of a
    second. The injuries associated with this event
    can last a lifetime. Protect yourself!
  • Electric Arc Flash Accident Video
  • (click on hyperlink to view)

Arc Blast
  • Extremely high-energy arcs can damage equipment,
    causing fragmented metal to fly in all
    directions. In atmospheres that contain explosive
    gases or vapors or combustible dusts, even
    low-energy arcs can cause violent explosions.
  • 480 volt 3-phase Arc Flash Demonstration Video
  • (click on hyperlink to view)

Arc Flash/Arc Blast
  • Damage to equipment, however, cannot compare to
    the damage suffered by victims of arc flash/arc
  • Donnie's Accident Video
  • (click on hyperlink to view)

Nature of Electrical Accidents
Electrical Accidents
  • can be generally considered as being caused
  • unsafe conditions
  • unsafe acts -or-
  • combinations of the two (the usual case)
  • plusthe environment is a contributory factor

Unsafe Conditions
  • Inadequate maintenance ? deterioration
  • faulty insulation
  • improper grounding
  • loose connections
  • defective parts
  • ground faults in equipment
  • unguarded live parts, and
  • underrated equipment

Unsafe Conditions
  • Inadequate wiring
  • Exposed electrical parts
  • Overhead powerlines
  • Overloaded circuits
  • Damaged power tools
  • Conductive ladders
  • Wrong PPE

Unsafe Acts
  • include the failure to de-energize electric
    equipment when it is being repaired or inspected,
  • the use of tools or equipment too close to
    energized parts.

The Environment
  • flammable vapors, liquids, or gases
  • areas containing corrosive atmospheres
  • wet and damp locations

Protective Measures
  • provides a barrier to the flow of current
  • to be effective, the insulation must be
    appropriate for the voltage
  • the insulating material must be undamaged, clean,
    and dry.

  • prevents the employee from coming too close to
    energized parts
  • can be in the form of a physical barricade
  • can be provided by installing the live parts out
    of employees' reach. (This technique is known as
    "guarding by location.")

  • is another method of protecting employees from
    electric shock
  • it is normally a secondary protective measure
  • to keep guards or enclosures at a common
    potential with earth, they are connected, by
    means of a grounding conductor, to ground
  • in addition, grounding provides a path of low
    impedance and of ample capacity back to the
    source to pass enough current to activate the
    overcurrent devices in the circuit

Design and Installation
  • to protect against dangerous arcing and
    overheating - it is also important in preventing
    unsafe conditions that can lead to fires, high
    energy electric arcs, and explosions
  • employers and employees cannot usually detect
    improperly designed or rated equipment
  • thus, OSHA relies on third-party testing and
    certification of electric equipment to ensure
    proper electrical design.

Significant Risk and Reduction in Risk
A Downward Trend?
  • While the number of deaths and injuries
    associated with electrical hazards has declined,
    contact with electric current still poses a
    significant risk to employees in the workplace,
    as evidenced by the numbers of deaths and serious
    injuries still occurring due to contact with
    electric current.

Heinrich Accident Triangle
Fatalities or Serious Injury
Injuries (Non-Disabling)
First Aid and Near Miss
Unsafe Actions and Conditions
How many times a day do you commit unsafe
acts? How long do you think you will get away
with them?
The Electrical Accident Triangle
What has changed? Now, how long do you think you
will get away with unsafe work behaviors?
OSHAs Final Ruling
  • The final standard carries forward most of the
    existing requirements for electrical
    installations, with the new and revised
    requirements intended as fine tuning, introducing
    new technology along with other improvements in
  • By complying with the final standard, employers
    will prevent unsafe electrical conditions from

  • National Electrical Code (NEC)
  • a 100-year legacy
  • has represented the continuing efforts of experts
    in electrical safety to address hazards and
    provide standards for limiting exposure in all
    electrical installations, including workplaces.

OSHA and 70E
  • NFPA 70E had only minor changes over its initial
    15 years of existence.
  • The first substantial changes were introduced in
    the 1995 edition of NFPA 70E.
  • The 2000 edition of NFPA 70E contains a number of
    significant revisions, including a new,
    alternative method for classifying and installing
    equipment in Class I hazardous locations.
  • NFPA has recommended that OSHA revise its general
    industry electrical standards to reflect the
    latest edition of NFPA 70E, arguing that such a
    revision would provide a needed update to the
    OSHA standards and would better protect

NFPA the National Fire Protection Association
Sponsor of National Electric Code (NFPA 70) and
Standard for Electrical Safety in the Workplace
(NFPA 70E).
70E Standard for Electrical Safety in the
Workplace. Developed by NFPA and used by OSHA as
a consensus standard.
  • January 7, 1976, Standards council of the NFPA
    announces formation of committee to develop 70E.
  • First edition published in 1979.
  • Updated every 3 to 5 years.

Four Parts
  • Safety Related Work Practices
  • Safety Related Maintenance Requirements
  • Safety Requirements for Special Equipment
  • Installation Safety Requirements

For more information on why 70E applies see
  • OSH Act of 1970 Sec. 5. Duties
  • OSHA 29 CFR 1910.1(a)

Electrical Fundamentals
Understanding Electricity
Voltage Force that causes the electrons to flow.
Volts V or E
Current The flow rate of electrons
Amps A or I
Resistance Opposition to current flow.
Ohms ? or R
Power Work over time.
Watts W or P
Insulators Vs. Conductors
Minimum Current Flow
Maximum Current Flow
Air Glass Rubber Ceramics
Gold Aluminum Copper Silver
Is skin a conductor or an insulator?
Is a conductor or an
  • Concrete, brick, and tile?

2005 NEC 110.26(A)(1) Condition 2
Fundamentals in Action
  • The Voltage from the source is applied across the
    Resistance in the body.
  • Current will flow through the body.
  • The result of Current flowing through the
    Resistance in the body is heat.
  • The amount of electrical energy being converted
    at the brain and heart is referred to as Power
    consumption and may lead to death.

Current Paths
Touch Potential
Step Potential
Current paths thru the heart are the most
Touch/Step Potential
Touch/Step Potential
What are the electrical hazards you face each and
every time you work on or around electrical
equipment? If you think S A F E before
you start work, it may help prevent an accident.
Shock Arc blast/flash Fire Electrocution
  • SAFE

Safe and Unsafe Current Values
Safe Current Values
1 to 8mA
- Sensation of shock
- Individual can let go at will
Unsafe Current Values
8 to 15mA
- Painful shock
- Individual muscle control is lost
15 to 20mA
- Painful shock
- Individual muscle control of
adjacent muscles is lost
20 to 100mA
- Painful shock
- Severe muscle contractions
- Breathing is difficult
100 to 200mA
- Ventricular fibrillation
- Loss of consciousness
- Electrical current holds victim to the
circuit as long as current is allowed to flow.
- Unless normal heartbeat is restored, with a
large DC pulse of current, death may result.
- Fibrillation threshold can range from 1A
depending on the duration of the shock and
the person's physical condition.
- Severe burns
- Muscular contractions severe enough to
cause the chest muscles to clamp the heart
and stop it throughout the duration of shock.
Qualified Vs. Unqualified
Qualified versus Unqualified
  • A qualified person is required to be trained.
  • They must be knowledgeable of how the specific
    equipment that they will be working on is
    constructed and operates.
  • They must understand the hazards involved with
    their job.
  • They must know the minimum approach distances
    that correspond to the voltage levels that the
    qualified person will be exposed to.
  • They must be able to determine if the use of
    special safety tools and equipment is necessary.

Qualified Person
  • The 2005 National Electric Code, Article 100
    defines a qualified person as
  • One who has skills and knowledge related to the
    construction and operation of the electrical
    equipment and installations.
  • And has received safety training on the hazards

70E Qualified Person
  • A qualified person shall be trained and
    knowledgeable of the construction and operations
    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. Such persons
    shall also be familiar with the proper use of
    special precautionary techniques, personal
    protective equipment, insulating and shielding
    materials, and insulated tools and test
    equipment. A person can be considered qualified
    with respect to certain equipment and methods but
    still be unqualified for others.

2004 NFPA 70E Section 110.6 Training
Requirements, (D)(1) Qualified Person
Qualified Person
  • Webster Dictionary
  • Competent, suited, or having met the requirements
    for a specific position or task.

  • 2002 National Electric Code Article 100
  • One who has skills and knowledge related to the
    construction and operation of the electrical
    equipment and installations and has received
    safety training on the hazards involved.

More Specific and Improved
  • 2004 NFPA 70E 110.6 (D)(1)
  • qualified person shall be trained - trained to
    recognize and avoid the electrical hazards. Such
    persons shall also be familiar with the proper
    use of special precautionary techniques, personal
    protective equipment, insulating and shielding
    materials, insulated tools, and test equipment

Very Specific and Detailed
Electrocution Deaths by Age Group
244 Victims In The Study
100 80 60 40 20 0
65 or gt
Age of Victims
NIOSH Fatality Assessment Control Evaluation
Voltage Levels and Fatalities
  • All other fatalities were over 600VAC
  • NFPA, OSHA, 70E all consider over 50 Volts to be

About Electrical Shock Victims
The highest percentage of electrical shock
victims are people who have lots of experience in
electricity and are very familiar with the
equipment that is being serviced.
About Electrical Shock Victims
The second highest group of victims of electrical
shock are professional and supervisory staff.
Supervisor in the Arc Flash Boundary
Attitudes, Emotions, Conditions
Multimeter Basics
Digital Multimeter
Analog Multimeter
Are You Qualified to Use This Meter???
  • Basic Meter Rules
  • Know how your meter functions and how it is
  • Always use industrial meters (A low-budget
    meter could kill you)

2004 NFPA 70E 110.9(A)
Solenoid Meters of Decent Quality!
  • Much lower impedance than DMM.
  • 1Kohm to 10Kohm input impedance.
  • Lower impedance means more current flow in
    meter and more effect on the circuit being
  • Meters that measure voltage on the higher end,
    may not read lower voltages
  • Low impedance input can cause GFCI to trip.

How would you like to be holding this one?
Meter self-destructed after receiving a high
Know Your Equipment
Hazardous and Exposed??
  • What are the exposed live sections?
  • What voltage levels are present?
  • Are there sections that can be manually activated?
  • If there are sections that can be manually
    activated is it safe for all employees to do so?

480 3?/60Hz
Drawing Number
4 Jan 1999
Conveyor System
Meter Explosion
Electrical Hazard Victim First Aid
Electrical Hazard Victim First Aid
  • The equipment or the appliance is turned off and
    de-energized at the control panel.
  • 2. If you cant turn off the power, use a rescue
    hook or a piece of wood, like a broom handle,
    to separate the victim from the power source.

Insulated Rescue Hook
2004 NFPA 70E Article 130.6 (D)(1)(d) Fiberglass-
Reinforced Plastic Rods. Fiberglass-reinforced
plastic rod and tube used for live line tools
shall meet the requirements of ASTM F 711,
Standard Specification for Fiberglass-Reinforced
Plastic (FRP) Rod and Tube Used in Live Line
Tools, 1989 (R 1997).
Electrical Hazard Victim First Aid
  • Do not try to move a victim
  • touching a high voltage wire.
  • Call for emergency help.

Electrical Hazard Victim First Aid
  • Assess the Victim
  • If the victim is conscious
  • Have a victim in burning clothing drop and roll
    to extinguish flames
  • Have the victim lie down
  • Elevate burned limbs to reduce swelling
  • Remove constricting items such as shoes, belts,
    jewelry and tight collars
  • Cover victims with clean, dry sheets or blankets
    to reduce shock. Wounds should be covered with
    sterile dressings or clean sheets.

Electrical Hazard Victim First Aid
  • Assess the Victim
  • If the victim is unconscious
  • and not breathing, begin rescue breathing
  • and has no pulse, begin CPR

Electrical Hazard Victim First Aid
  • Special Considerations
  • Handle the victim with care as they may have
    broken bones or spinal injuries
  • Treat for shock maintain body temperature, do
    not give anything by mouth administer high
    concentrations of oxygen, if available
  • When calling for help, assign a particular
    coworker to make the call. If not, people may
    assume someone else already made the call and
    response time from qualified health care workers
    will suffer

Understanding Lockout/Tagout
LOTO where to find it
Federal Code of Regulations available from the
United States Government Printing Office U.S.
Government Bookstore Ph. 412-395-4547
Sections that are relevant to Lockout/Tagout
  • 1910.147 The control of hazardous
  • 1910.147A Typical MINIMAL Lockout Procedure.
  • 1910.331-335 Safety Related Work Practices.

Energy Control Program
All companies must have an ECP (Energy Control
An ECP consists of the following
  • Energy Control Procedures
  • Employee Training
  • Periodic Inspections

OSHA uses some vague terminology when writing
Lockout/Tagout regulations. In order to gain a
better understanding the definitions must be
Affected Employee An employee whose job
requires him/her to operate or use a machine or
equipment on which servicing or maintenance is
being performed under lockout or tagout, or whose
job requires him/her to work in an area in which
such servicing or maintenance is being performed.
Authorized Employee A person who locks out or
tags out machines or equipment in order to
perform servicing or maintenance on that machine
or equipment. An affected employee becomes an
authorized employee when that employees duties
include performing servicing or maintenance
covered under this section.
Note this is not the definition of a qualified
Stored Energy
Following the application of lockout tagout
devices to energy isolating devices, all
potentially hazardous stored or residual energy
shall be relieved, disconnected, restrained, and
otherwise rendered safe.
If there is a possibility of re-accumulation of
stored energy to a hazardous level, verification
of isolation shall be continued until the
servicing or maintenance is completed, or until
the possibility of such accumulation no longer
Personal Protective Equipment
Personal Protective Equipment, PPE
  • 29 CFR (Code of Federal Regulations)
  • 1910.335(a) Use of protective equipment
  • Personal protective equipment
  • (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.
  • (iv)Employees shall wear nonconductive head
    protection wherever there is a danger of head
    injury from electric shock or burns due to
    contact with exposed energized parts.
  • (v)Employees shall wear protective equipment for
    the eyes or face wherever there is danger of
    injury to the eyes or face from electric arcs or
    flashes or from flying objects resulting form
    electrical explosion.

Personal protective equipment, PPE 1910.335
29 CFR1910.335(a) (2) General Protective
Equipment and Tools
(i) When working near exposed energized
conductors or circuit parts, each employee shall
use insulated tools or handling equipment if the
tools or handling equipment might make contact
with such conductors or parts. If the insulating
capability of insulated tools or handling
equipment is subject to damage, the insulating
material shall be protected. (ii) Protective
shields, protective barriers, or insulating
materials shall be used to protect each employee
from shock, burns, or other electrically related
injuries while that employee is working near
exposed energized parts which might be
accidentally contacted or where dangerous
electric heating or arcing might occur. When
normally enclosed live parts are exposed for
maintenance or repair, they shall be guarded to
protect unqualified persons from contact with the
live parts.
PPE Assessment
NFPA 70E provides two methods to determine what
type of PPE is required. Preferred Method
Flame resistant clothing and PPE shall be
selected based on the incident energy exposure
from the Flash Hazard Analysis. Alternative
Method Use the matrix in 70E Table 130.7
(C)(9)(a) to determine the Hazard/Risk Category
based on the task. From the Hazard/Risk Category
the appropriate PPE shall be selected.
FR Clothing Use
Layering FR and natural fiber garments (cotton)
can be used in a layered system to give added
Outer Layers If using rain wear or other
outside wear the material must be FR rated.
Under-layers Meltable synthetic fibers shall be
Fit Fit of clothing shall be loose. Air spaces
add to the thermal insulating value. FR clothing
shall fit so that it does not interfere with the
work task.
Interference The clothing shall result in the
least interference with the task, but still
provide the necessary protection.
Inspection FR apparel shall be inspected before
each use.
Importance of Arc Flash Analysis
1500 kVA 13.8/0.480 kV 24 kA-Bolted
Fault 13.06ka-Arcing Fault 1.25 Second Clearing
Time 18 inch working distance 53.7 cal/cm2
1500 kVA 13.8/0.480 kV 30 kA-Bolted
Fault 15.72ka-Arcing Fault 0.13 Second Clearing
Time 18 inch working distance 7.0 cal/cm2
Hazard Risk 2 PPE Realistic to Protect
Above Hazard Risk 4 PPE May Not Be Survivable!
Fire Resistant Clothing
Fire Resistant Clothing shall have a ATPV value.
ATPV Arc Thermal Performance Exposure Value
ARC rating is available from the FR clothing
ATPV concerns two items 1) The amount of
incident energy that it takes to cause just the
onset of a second degree burn. 2) The highest
amount of incident energy that did not cause the
FR fabric to break open.
Arc Flash Analysis Vs. Using the Tables
Example 208 Volt Panel 4,200 Amps Arcing Fault
Clearing Time Over 2 Seconds Table Category
1 Calculated Category 4
Example 480 Volt Motor Control Center 16,000
Amps Arcing Fault Clearing Time .01
Seconds Table Category 2 w/ Double Layer
Hood Calculated Category 0
Both examples, when removing bolted covers.
(No Transcript)
Sample Tasks and Appropriate PPE
Panelboards Rated 240V and Below
  • Based on 25kA short circuit current available,
    .03 second (2cycle) fault clearing time.
  • If the short circuit current in less than 10kA
    available the Hazard Risk can be reduced by 1.

Sample Tasks and Appropriate PPE
Panelboards or Switchboards rated 240V-600V with
molded case or insulated case circuit breakers or
fused switches.
Panelboard a single or group of panels designed
to be assembled to form a single panel and placed
inside a cabinet. Accessible from the front
only. Switchboard - a large single panel frame.
Switchboards are typically accessible from the
front and rear and are not intended to be
installed in cabinets.
  • Based on 25kA short circuit current available,
    .03 second (2cycle) fault clearing time.
  • If the short circuit current in less than 10kA
    available the Hazard Risk can be reduced by 1.

Sample Tasks and Appropriate PPE
600V Class Motor Control Centers (MCCs) and
  • 65kA Short Circuit Current Available, .03 sec
    fault clearing time.
  • A double layer switching hood and hearing
    protection are required for this task in addition
    to the other Hazard/Risk Category 2 PPE

Sample Tasks and Appropriate PPE
600V Class Motor Control Centers (MCCs) and
  • 65kA Short Circuit Current Available, .03 sec
    fault clearing time.
  • A double layer switching hood and hearing
    protection are required for this task in addition
    to the other Hazard/Risk Category 2 PPE

Minimum Arc Rating of Personal Protective
Equipment - N/A Personal Protective clothing
shall be non-melting (according to ASTMF 1506-00)
or natural fiber. - Cotton Underwear - Shirt
(long sleeve) - Pants (long) - Safety Glasses or
Goggles (according to ANSI Z87.1) Electrical
Shock Hazard - Voltage Rated Gloves (according
to ASTM D 120-02) - Leather Covers (according to
ASTM F 696-02) - Voltage Rated Tools (according
to ASTM F 1505-94 or EN 60900)
Minimum Arc Rating of Personal Protective
Equipment - 4 cal/cm2 - Cotton
Underwear - Flame Resistant Shirt (long
sleeve) - Flame Resistant Pants (long) or
untreated, denim cotton blue jeans (minimum12
oz/yd2 fabric weight) - Flame Resistant Coverall
- Alternate to FR Shirt and Pants - Hard Hat
(according to ANSI Z89.1) - Safety Glasses or
Goggles (according to ANSI Z87.1) - Leather
Gloves Electrical Shock Hazard - Voltage Rated
Gloves (according to ASTM D 120-02) - Leather
Covers (according to ASTM F 696-02) - Voltage
Rated Tools (according to ASTM F 1505-94 or
EN 60900)
Minimum Arc Rating of Personal Protective
Equipment - 8 cal/cm2 - Cotton
Underwear - Cotton t-shirt - Flame Resistant
Shirt (long sleeve) - Flame Resistant Pants
(long) - Flame Resistant Coverall - Alternate to
FR Shirt and Pants - Hard Hat (according to ANSI
Z89.1) - Safety Glasses or Goggles (according
to ANSI Z87.1) - Arc Flash Rated Face Shield
(ANSI F 2178-02) or Flash Suit Hood - Hearing
Protection - Leather Gloves - Leather
Shoes Electrical Shock Hazard - Voltage Rated
Gloves (according to ASTM D 120-02) - Leather
Covers (according to ASTM F 696-02) - Voltage
Rated Tools (according to ASTM F 1505-94 or
EN 60900)
Minimum Arc Rating of Personal Protective
Equipment - 25 cal/cm2 - Cotton
Underwear - Cotton t-shirt - Flame Resistant
Shirt (long sleeve) - Flame Resistant Pants
(long) - Flame Resistant Coverall - Alternate to
FR Shirt and Pants - Hard Hat (according to ANSI
Z89.1) - Flash Suit Hood - Safety Glasses or
Goggles (according to ANSI Z87.1) - Hearing
Protection - Leather Gloves - Leather
Shoes Electrical Shock Hazard - Voltage Rated
Gloves (according to ASTM D 120-02) - Leather
Covers (according to ASTM F 696-02) - Voltage
Rated Tools (according to ASTM F 1505-94 or
EN 60900)
Minimum Arc Rating of Personal Protective
Equipment - 40 cal/cm2 - Cotton
Underwear - Cotton t-shirt - Flame Resistant
Shirt (long sleeve) - Flame Resistant Pants
(long) - Flame Resistant Coverall - Alternate to
FR Shirt and Pants - Hard Hat (according to ANSI
Z89.1) - Multilayer Flash Suit
Jacket - Multilayer Flash Suit Pants - Flash Suit
Hood - Safety Glasses or Goggles (according to
ANSI Z87.1) - Hearing Protection - Leather
Gloves - Leather Shoes Electrical Shock
Hazard - Voltage Rated Gloves (according to
ASTM D 120-02) - Leather Covers (according to
ASTM F 696-02) - Voltage Rated Tools (according
to ASTM F 1505-94 or EN 60900)
Gloves must be tested
1910.137 Table I 6 Rubber insulating gloves
Before first issue and every 6 months
thereafter. If the insulating equipment has been
electrically tested but not issued for service,
it may not be placed into service unless it has
been electrically tested within the previous 12
Ask to see the inspection sheet!
Leather Protectors
2004 NFPA 70E 130.7(C)(13)(c)
Where voltage-rated gloves are used, leather
protectors shall be worn over the rubber gloves.
Glove Checking
  • Gloves must be checked before each use
  • Roll-up test - Used when inflator is not
  • Inflator test More thorough

Maximum Inflation Size Type I Gloves 1.5 times
normal Type II Gloves 1.25 times normal
Conductive Articles Being Worn
Conductive articles of clothing or jewelry shall
not be worn when they present an electrical
contact hazard. Examples of conductive material
  • Rings
  • Watchbands
  • Bracelets
  • Necklaces
  • Metal frame glasses
  • Key chains

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Insulated Tools
European association for Electrical, Electronic
Information Technologies
IEC international safety symbol
Up to 1000 Volts
NFPA 70E 130.7(16)(D)(1) Employees shall use
insulated tools and/or handling equipment when
working inside the Limited Approach Boundary of
exposed live parts where tools might make
accidental contact.
Other Protective Methods
Barricades shall be used in conjunction with
safety signs where it is necessary to prevent or
limit employee access to work areas containing
live parts. Conductive barricades shall not be
used where it might cause an electrical hazard.
Barricades shall be placed no closer than the
limited approach boundary.
2004 NFPA 70E 130.7(E)(2)
Access by Qualified personnel only
If signs and barricades do not provide sufficient
warning and protection from electrical hazards,
an attendant shall be stationed to warn and
protect employees.
2004 NFPA 70E 130.7(E)(3)
Clearance Distances
Flash Boundary Moves
Flash Protection Boundary
Enclosures concentrate blast in one direction.
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Appendix Electrical Safety Case Studies
Arc Blasts/Flash Reference Page
Arc Blast Pressure wave caused by Arc Flash
  • Pressures can reach 200 lbs/sq. inch.
  • Temperature can be up to 35,000?F.
  • Surface temperature of the sun 10,000?F.
  • Pressure Waves A person standing 2 feet away
    from a 25,000 amp arc would experience a force of
    approximately 480 pounds.
  • Projectiles Pressure waves can snap the heads
    off of 3/8-inch steel bolts.
  • Conductors can be vaporized.
  • Vaporized copper will expand approximately
    67,000 times making molten particles similar to
  • Enclosures will concentrate energy.

Injuries may include
  • Severe burns
  • Broken Bones
  • Vision damage
  • Hearing damage
  • Concussions

Qualified Operator
SUBJECT Printing Company Bindery Machine
Operator SUMMARY A male bindery machine
operator was electrocuted when he contacted a
480-volt circuit inside a panel box while trying
to check an electrical relay. The victim, a
gilter operator, had stopped his machine to
change sanding belts. Afterwards, the machine
stopped and the victim could not restart it. To
determine whether the circuit breaker on his
machine had tripped, the victim walked to the
480-volt electrical panelboard and opened the
unlocked right-hand door. The left-hand door is
designed to permit entry only after the power
handle on the door is turned to the "off"
position, ensuring that the panelboard is
de-energized before entry. The victim tried to
open the left-hand door while maintaining power
to the circuits supplied by the panel. To do
this, he held the left-hand door handle with his
left hand, and reached behind the door with his
right hand to release the safety lock. His right
hand contacted an energized conductor.
Electricity passed through his body from his
right hand to his left hand, and then to ground
through the door handle. A co-worker saw the
incident and turned the power handle to the "off"
position. Co-workers provided CPR, but
resuscitation failed. What caused this death?
Qualified Electrician
SUBJECT Electrician Electrocuted CAUSE
Electrocution SUMMARY A 33-year-old male
journeyman electrician was electrocuted when he
contacted an energized wire in a fluorescent
light fixture in a private residence. The victim
and a helper were repairing an electrical system
at a private residence. At 425 P.M., the victim
called his office to notify his supervisor that
the work could not be completed by the normal
quitting time of 430 P.M. The helper had been
trying to repair a 110-volt, 4-foot-long
fluorescent light over a stainless-steel sink in
the kitchen. He had replaced the ballast but
could not get the light to work properly. The
helper asked the victim for assistance. The
victim was sitting on the sink when he apparently
contacted an energized wire on the load side of
the ballast. The circuit had not been
de-energized either at the panel box or at the
single-pole switch on the wall beside the sink.
It is not clear whether the victim knew the
circuit was energized or not. At 435 P.M. the
homeowner discovered the victim and pulled him
away from the light. The helper and homeowner
contacted the Fire Department and tried to make
the victim comfortable. The victim responded that
he was all right. Fire Department personnel
arrived at 450 P.M. and transported the victim
to a nearby hospital, where he was pronounced
dead a short time later. The cause of death was
cardiac arrhythmia due to electrocution. Later
investigation determined that the voltage on the
load side of ballast was 400 volts. The reason
the light would not work was that the lamp was
burned out.
SUBJECT 34-Year-Old Superintendent of
Manufacturing CAUSE Electrocution SUMMARY On
Sunday, 34-year-old male superintendent of
manufacturing was electrocuted while inspecting
electrical relays in an electrical control
box. The company uses refiners to grind wood
chips into mulch fibers. The superintendent was
notified at home that a refiner motor would not
start. The superintendent arrived at the plant at
300 P.M. Sunday. He began searching for an
electrical failure accompanied by the plant
manager and the shift foreman. The men did not
find one in the control panel on the exterior of
the building. They entered a restricted room to
check a control panel box inside the facility.
The victim stood on a metal stool in front of the
7-foot by 3-foot by 9-foot control panel box. He
opened the double metal doors and visually
examined the upper half of the circuitry. After
several minutes of leaning into the dark box, the
victim asked for and was given a flashlight. A
few seconds later the victim received a shock and
asked for help. The foreman tried to pull the
victim back by the waist, but also received a
shock. The foreman then grabbed the victim by the
belt and pulled him to the floor. The foreman
began CPR, but to no avail. An investigation
discovered a detached 220-volt conductor in the
panel box. Apparently the victim lost his balance
and supported himself by placing his hand against
the inside of the panel. The victim had an entry
wound on the right index finger and exit wounds
in the middle of the left wrist.
Mind On The Job
SUBJECT Electrocution of an Electrician SUMMARY
A male class A electrician with about 10 years
experience was working at a non-union coal-fired
power plant. At about noon, he was electrocuted
while replacing a limit switch on a coal sampler.
The victim had been on vacation up to and
including the day before the incident. By 1130
A.M. on the 13th, the victim received a briefing
on the need to replace a limit switch. The victim
walked to the building containing the coal
sampler and supposedly took a normal lunch break
from 1145 A. M. to 1215 P.M. At about 1225
P.M. three workers were riding a manlift up to
the fourth floor of the building. As they reached
the third floor, they saw the victim lying
face-up underneath a conveyor belt. On the ground
next to the victim were a pack of cigarettes and
two folded one-dollar bills. The body had no
signs associated with a fall and was not in a
position that would result from a fall.
Examination of the body showed electrical burns
on the right hand, aspiration of foodstuff into
the secondary and tertiary bronchi, contusion of
the left mastoid scalp, and abrasion of the right
mid-tibial area. The medical examiner concluded
that the cause of death was electrocution.The
probable sequence of events follows The victim
was standing on the conveyor belt guard
installing the new limit switch. Two of the three
wires were connected and the victim was
connecting the last wire, the 220-volt hot wire.
Coming out of the conduit, the wire was too short
to reach the switch. Probably, the victim grabbed
the wire with his right hand and attempted to
pull it further out of the conduit. As he did,
the bottom of part of his hand contacted the
limit switch. When the wire hit the upper part of
his palm, a circuit was completed. Due to the
relatively low voltage, the victim was not killed
instantly his heart probably went into
arrhythmia. He probably felt uncomfortable,
decided to get down and have a smoke, and died
seconds later.
SUBJECT Welder Electrocuted by Contact With an
Energized Overhead Crane ConductorCAUSE
Electrocution SUMMARY On July 9, a 41-year-old
male welder was electrocuted when he contacted an
energized overhead crane contact conductor. The
victim was one of 490 employees of a steel
fabricator. The victim worked a production shift
from 500 A.M. to 1200 noon and was then asked
to work overtime with a co-worker. The job was to
add reinforcing steel to the bridge of an
overhead crane. The crane was one of three
rail-mounted, overhead-traveling cranes that ran
the length of the 600-foot building. Directly
below these units was a smaller rail-mounted
crane serving only one end of the shop (about 150
feet). Power for the large cranes was provided
through collector leads by a 440-volt circuit,
which was composed of three bare copper contact
conductors running below the cranes for the
length of the building. An identical power supply
for the small crane ran parallel to and about 8
feet below these conductors. Power for the large
crane was disconnected before work began. The
workers believed that the small crane had also
been disconnected by other workers, but this was
not the case. The temperature may have exceeded
100 degrees Fahrenheit. Instead of moving the
crane to a location that offered ladders and was
physically isolated from the contact conductors,
the victim and his co-worker climbed lattice
columns on each side of the shop. After working
on the large crane for 1.5 hours, the two workers
climbed down. The victim left the column he was
climbing and sat on a crossbrace, presumably to
rest. His head contacted one of the small crane's
contact conductors, and he collapsed on the
crossbrace. The supervisor turned off the power
to the small crane contact conductors and
summoned EMS personnel, but to no avail.
Not Coming Home
SUBJECT 25-Year-Old Restaurant Manager
Electrocuted CAUSE Electrocution SUMMARY A
25-year-old male restaurant manager was cleaning
the floor of the kitchen when he came in contact
with a refrigerator that had a ground fault. The
manager was electrocuted. The restaurant was
closed and the manager's wife and 2-year-old
daughter were in the dining area waiting for him
to finish. The victim, who was wearing tennis
shoes, put soap and water on the floor. He
slipped and grabbed the handle of a commercial
refrigerator. The refrigerator had a ground fault
and was not grounded -- the cord did not have a
ground prong. The ground fault was apparently
caused by excessive wear on the insulation of the
conductors (wires) supplying power to the
compressor. The conductors were exposed at a
cut-out hole in the case of the refrigerator,
were not protected from abrasion, and were not
protected by strain relief. The victim's wife
heard a noise in the kitchen. She successfully
pulled the victim from the refrigerator into the
dining area, though she was shocked in the
process. She summoned help and began CPR, but to
no avail.
Poor Judgment
SUBJECT 22-Year-Old Construction Worker
Electrocuted CAUSE Electrocution SUMMARY A
22-year-old male carpenter was electrocuted when
a portable electric saw he was using apparently
developed a ground fault. The victim was an
independent contractor working at the
construction site of a 396-unit apartment
complex. He was constructing the wooden framework
of a laundry building. Electricity to operate
portable power tools was supplied by a temporary
service pole 50 feet away. The pole had not been
inspected by the city and was not in compliance
with code requirements. (It was not grounded.)
The panel box on the pole had two duplex
receptacles (outlets) in weatherproof boxes. One
was a regular receptacle and the other was a
ground fault circuit interrupter (GFCI)
receptacle. The victim used two extension cords
to supply power a home-made cord plugged into
the regular receptacle on the pole, and a
UL-approved cord extending from the home-made
cord to the power saw. The accident site was wet.
Humidity was high and the victim was sweating.
Reportedly, he was shocked throughout the
morning, and had replaced one of the extension
cords in an effort to eliminate the shocks. The
source of the shocks -- the saw -- was not
replaced. At the time of the incident, the victim
was climbing down a makeshift ladder (a piece of
floor truss). He shifted the power saw from his
right hand to his left, and was shocked. He fell
from the ladder into a puddle of water, still
holding the saw. Apparently, his hand contracted
and he was "locked" to the saw. A co-worker
disconnected the power cord to the saw. CPR was
given, to no avail. The victim had burns on his
left hand and his left thigh.
Terrible Conditions
SUBJECT General Laborer Electrocuted CAUSE
Electrocution SUMMARY A 17-year-old male
seasonal general laborer at a pickle plant was
electrocuted when he contacted a faulty splice on
a 440-volt power cord. The victim and a co-worker
were filling a wooden tank with pickling brine
(45 salinity) using a 2-inch hose. The tank was
accessed by an above-ground wooden platform. When
the tank was full, the victim called to the
co-worker to turn off the valve. When the valve
was closed, the victim dropped the hose on the
platform, allowing brine to drain onto the
platform. A portable pump was also on the
platform. It was turned off, but its power cord
was plugged into a pole-mounted power box about
45 feet away. After dropping the hose, the victim
stepped away from the tank and onto the power
cord. He immediately shouted and leaned back
against the tank in an upright position. The
co-worker moved to the victim, but on reaching
the brine-soaked area he felt electric current
running into his foot and leg. He jumped back and
yelled to a second worker to turn off the
electricity. The second worker could not find the
switch box and so notified the crew chief. The
crew chief ran to the site, saw what was
happening, ran to the switchbox and turned off
the power. He then returned to the site where he
and the second worker administered CPR, to no
avail. Upon examination a faulty splice was found
in the power cord. Two leads were exposed, which
allowed them to energize the brine. The victim's
canvas shoes and pants were also saturated with
brine. The salt in brine makes it more conductive
than plain water.
Proper Tools, Proper Methods
SUBJECT Textile Worker (Fixer) Electrocuted
When He Contacts an Energized Conductor CAUSE
Electrocution SUMMARY A 44-year-old male fixer
was electrocuted at a textile plant when he
contacted an energized electrical conductor
inside the 550-volt control box of a carding
machine. The victim and a co-worker arrived at
the plant 1 hour before the midnight-to-800 A.M.
shift to start the 42 carding machines. The
victim proceeded down the line of machines,
pushing the start buttons. Forty of the machines
started and two did not. On his second round to
check the machines, the victim restarted one
machine. The remaining machine's control box had
overheated for undetermined reasons, prohibiting
the machine from being restarted. The victim
positioned himself in front of the control box
then opened the door. He held one end of a
screwdriver against the reset button with his
right hand, while the other end of the
screwdriver rested against his abdomen. The
victim held the metal nozzle of an air hose with
his left hand and directed a stream of air into
the control box. At some point the metal nozzle
contacted an energized conductor inside the
control box. Current passed through the nozzle
and victim's left hand exiting through the
victim's abdomen and screwdriver to ground,
electrocuting the victim.
Machine Overload Fans
SUBJECT Textile Worker (Machine Operator)
Electrocuted After Contacting an Energized
Conductor CAUSE Electrocution SUMMARY A
19-year-old male sueder machine operator was
electrocuted when he contacted an energized
conductor inside the electrical control panel of
a sueder machine. Before the incident the victim
had been operating two sueder machines at a
textile plant for 9 to 10 hours. The 5- and
10-horsepower motors in the two machines had a
regular tendency to overheat when heavy cloth was
processed, because heavier-weight material
increased the tension on the machines' rollers,
producing added friction and heat. Overheating of
the motors would trip the overload relays and
shut down the machines. The control panel covers
on the two machines had previously been modified
to increase heat dissipation. On the day before
the incident the cover on machine 7 had been
removed altogether, without authorization. On the
day of the incident the victim apparently
attempted to cool the uncovered electrical
equipment inside the control panel of machine 7
with a stream of compressed air from an air hose.
The metal nozzle of the hose contacted an
energized conductor inside the control panel.
Current passed to ground through the nozzle, the
victim's hand, his chest, his other hand, and
through one of the other machines that the victim
was touching.
Damaged Cord
SUBJECT Construction Laborer Electrocuted After
Handling Damaged Energized Extension Cord
CAUSE Electrocution SUMMARY A 19-year-old
male construction laborer was electrocuted after
handling a damaged extension cord that was
energized. The victim, a second laborer, and a
foreman were constructing a waterfront bulkhead
for a residence at the edge of a lake. Electric
power was supplied from an exterior 120-volt,
grounded AC receptacle (outlet) located at the
back of the residence. On the day of the
incident, the victim plugged in a damaged
extension cord and laid it out towards the
bulkhead. There were no eyewitnesses of the
incident. However, evidence suggests that while
the victim was handling the damaged and energized
extension cord, he provided a "path to ground,"
and was electrocuted. The victim collapsed into
the lake and sank 4.5 feet to the bottom.
SUBJECT 24-Year-Old Manufactured-Home Installer
Electrocuted CAUSE Electrocution SUMMARY A
24-year-old male worker was electrocuted when
using a 110-volt auger to install tie-down rods
for a manufactured home. The ground was wet, and
the machine had no continuous grounding system. A
second worker was also shocked. The two workers
were under the home installing tie-down anchor
rods. The steel rods are screwed into the ground
either manually or with an electric auger
machine. The auger has a one-quarter-horsepower
motor encased in a metal housing with two
handles. One handle has a deadman's switch. Two
people usually operate the auger, but it can be
operated by one. Electricity to the auger was
supplied by series of 50-foot extension cords
running to an adjacent property. The outlet at
the adjacent property had no socket for a ground
prong, and the extension cords were plugged into
the outlet using an adapter. The ground wire of
the adapter was not grounded. Two of the
extension cords had no ground prongs, and some of
them were repaired with electrical tape. The
extension cords were tied in knots at each
connection and the connections were placed on
concrete blocks. The rest of the cord was on wet
grass, mud, and wet pea gravel. The workers under
the home had removed their shirts and were
sweating. One worker, holding the deadman's
switch, received a shock from a ground fault in
the auger and was knocked back from the machine.
The auger then fell across the other worker, the
victim. The first worker knocked the auger off
the victim, but saw that the electric cord was
wrapped around the victim's thigh. He yelled for
the workmen working inside the home to disconnect
the power, which they did. The workers
administered CPR, but to no avail.
Too Much Time
SUBJECT 32-Year-Old Electrician Electrocuted
CAUSE Electrocution SUMMARY A 32-year-old
male electrician was electrocuted while replacing
a socket on an energized fluorescent light
fixture. His hand presumably contacted an
energized single-strand wire on the secondary
side of the ballast. At about 145 A.M., a
maintenance foreman directed two journeyman
electricians to replace bulbs and make repairs on
fluorescent light fixtures in a spray paint booth
at an automobile assembly plant. The spray booth
is 50 feet long. Six-foot-long fixtures are
mounted end to end on the ceiling of the booth.
Several fixtures needed new sockets and ballasts.
The work required that the two electricians climb
on top of the booth and work from above. The top
was congested with pipes and ducts that
obstructed visibility and restricted movement.
Flashlights were required. The electricians
started at opposite ends of the booth. One
electrician saw a flash of light. He continued to
work for about 5 minutes and then climbed down
for some wire. While cutting wire he smelled a
burning odor, and called to the other
electrician. He received no reply, and climbed up
to find the victim in contact with a
single-strand wire from the secondary side of the
ballast on one of the fluorescent lights.
Needle-nose wire strippers were stuck in the left
side of the victim's chest. It is assumed that
the victim was stripping insulation from the
improperly grounded 530-volt single-strand wire
when he contacted it. The electricians knew they
were working on energized fixtures. The breakers
within the control panel were not labeled and the
lock used for lockout/tagout was inoperable.
Co-workers stated that locating the means to
disconnect a circuit often required more time
than the actual completion of the task.
Sacrificed for a Popsicle Machine
SUBJECT 29-Year-Old Electrocuted at Ice Cream
Plant CAUSE Electrocution SUMMARY A
29-year-old male maintenance man was
trouble-shooting an electrical problem with a
popsicle-wrapping machine when he was
electrocuted. The operator of the machine
notified the maintenance man that the machine was
not working. The victim responded. When he
pressed the reset button, the machine ran for 10
minutes and stopped. The victim obtained an
electrical testing device from his shop. He took
the metal cover from the control box of the
machine, which housed three reset controls and a
fuse. He tried to start the machine with the
reset buttons but was unsuccessful. The victim
was standing on a metal platform elevated one
foot from the floor. The floor was wet. A few
minutes later the machine operator heard a moan
and noticed the victim slumped over with his hand
in the control box. Two of the victim's fingers
were inside the control box, contacting a
230-volt energized circuit. A co-worker went
across the room and shut off the main control
switch to the machine. Co-workers called EMS and
administered CPR, but the victim was dead on
arrival at a local hospital.
Electrical Safe Work Practices
This training program was developed by Purdue
University North Central, the Construction
Advancement Foundation, the City of Michigan
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