Introduction to arc flash

Online Continuing Education Training for Professionals
Guaranteed Acceptance by Licensing Boards or 100% Refund
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Introduction to Arc Flash
HS-02-104W
PDH Credits: 3
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Learning Objectives
After this course, you will:
–Understand the Arc Flash Hazard
–Recognize National Consensus
Standards on the topic
–Be familiar with the
OSHA requirements

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Course Agenda
–Introduction to Arc Flash
–National Consensus Standards
–The OSHA Position

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Arch Flash
Arc flash or arc blast is:
–The arc of high-amperage currents
through the air.
–A discharge of high voltages across
a gap between conductors
• The current travels through the air
• Temperatures as high as
35,000° Fahrenheit

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Causes
What causes an arc flash?
–Bridging electrical contacts with a
conducting object
–Dropped tools
–Buildup of conductive dust or
corrosion

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Arc Flash Conditions
Arc flash conditions:
–Working on an energized circuit
–Electrical equipment failure

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Arc Flash Hazards
Three primary hazards:
1. Thermal radiation and intense heat
2. Pressure wave blast
3. Molten metal
Arc Blast Hazards

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Thermal Radiation and Intense Light
Factors affecting degree of injury:
– Skin color
– Area of skin exposed
– Type of clothing worn
To reduce risk of burn:
– Proper clothing
– Work distances
– Over-current protection

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Pressure Waves
Pressure wave blast:
–25,000-amp arc:
• Feels like a force of about 480 pounds
• May cause serious ear damage
• May result in memory loss due to
concussion
Pressure wave may throw victim:
–May propel objects over
great distances

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High Voltage Arcs
High-voltage arcs can melt electrical
equipment:
–Molten metal may be propelled great distances

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National Consensus Standard
–Promulgated by a nationally recognized standards-
producing organization
–Offers opportunity to consider diverse views
–Designated by the Secretary

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Overview
–Only national consensus standards that have been
adopted as, or specifically incorporated by
reference into, an OSHA standard provide a means
of compliance with the OSH Act
–While requiring employers to comply with OSHA
standards, the OSH Act also authorizes OSHA to
treat certain violations, which have no direct or
immediate relationship to safety and
health, as de minimis, requiring
no penalty or abatement
The OSH Act

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NPFA 70E: Standard for Electrical
Safety in the Workplace
–Wide range of electrical safety issues
–Assist employers comply with OSHA
standards
Workplace Standards

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1. Creating an electrically
safe work condition
2. Training workers
3. Planning the task
4. Selecting and using personal protective
equipment
Protective Strategies

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Terminology
Understanding terminology is
essential to implement control
measures

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Arc Flash Hazard Analysis
–Measures incident energy that may strike
an employee
–Determines the arc flash protection
boundary
–Establishes the personal protective
equipment necessary
–Helps create practices to accomplish
the desired work
Arc Flash Hazard Analysis

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Working Distance
The working distance:
–Distance from where worker stands to flash location
–Common distance is 18 inches
–Incident energy can be used to
select protective equipment
Working Distance

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Incident Energy
–Measure of thermal energy at working distance
from an arc fault
–Measured in Calories per square Centimeter,
or cal/cm2
–2nd degree burn of human
skin is at 1.2 cal/cm2
Incident Energy

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Arc Flash Protection Boundary
The Arc Flash Protection Boundary is the
distance from which a person could receive a
second degree burn

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How to Use NFPA 70E
NFPA 70E is valuable in complying with the
OSHA electrical standards

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OSHA Use of National Consensus Standards
OSHA standards as they relate to NFPA
70E:
–OSHA does not enforce requirements of
NFPA 70E
–NFPA 70E can be used by OSHA and
employers as guides in making hazard
analyses and selecting control measures
OSHA’s Position

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The General Duty Cause
Does OSHA issue General Duty Clause violations to companies who
do not follow the new NFPA 70E?
– A violation of the General Duty Clause exists if an employer fails to
furnish a workplace that is free from recognized hazards
– The General Duty Clause is not used to enforce the provisions of
consensus standards
– The General Duty Clause usually
is not used if there is a
standard that applies to the
particular condition, practice,
means, operation, or
process involved

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Marking of Electrical Equipment
OSHA has no specific requirement for marking of
electrical equipment to warn qualified persons of
potential arc flash hazards.
–Paragraph (e) of 1910.303 requires employers to mark
electrical equipment with descriptive markings,
including the equipment's voltage, current, wattage, or
other ratings as necessary

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Flame-Resistant Clothing
Is flame-resistant clothing required for employees working on electrical
installations covered by Subpart S?
– OSHA's present requirements in Subpart S, Safety-Related Work
Practices, are based on NFPA 70E-1983, which did not at that time
include specific provisions for
flame-resistant clothing
– More recent versions of NFPA 70E
have included such body
protection provisions
– OSHA's existing Subpart S does
not include a specific requirement
for fire-resistant clothing

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OSHA-Requires De-energization
OSHA provisions for selection and use of work
practices contained in 1910.333(a)(1) generally
require de-energization of live parts before an
employee works on or near them.
– Exposure is limited to when the equipment is
shut down and when the qualified employee
verifies, by use of a test instrument, a de-
energized state
– When employees perform work on energized
circuits, as permitted by 1910.333(a)(1), tools and
handling equipment that might make contact
with exposed energized parts must be insulated
in accordance with 1910.335(a)(2)(i)

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Additional OSHA Requirements
Personal protective Equipment (PPE):
–Must be worn for eyes and face when there is
danger of injury
–Use equipment to protect employees from:
• Electric shocks
• Blast
• Arc flash burn hazards

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Supplemental Steps to Ensure Worker Safety
NFPA 70E-2004 standards:
–Arc Flash Hazard analysis
–Flash-protection boundary
–Personal protective equipment
NFPA 70E, Article 130 provisions:
–Energized electrical work
authorization permit
–Brief employees before they
start each job

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Additional Information
29 CFR 1910 Subpart S, Electrical
National Fire Protection Agency:
NFPA 70E: Standard for Electrical
Safety in the Workplace®
2009
OSHA 3075: Controlling Electrical
Hazards 2002

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Congratulations!
Your Introduction to Arc Flash training is
complete
•Next Steps
– Watch video – login to your account
– Review handouts
– Complete exam
– Certificate of Completion

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Next Steps
1. Download - Course Materials and Quiz
http://www.pdh-pro.com/Courses/Webinar/HS02104W.html
2. Review Materials and Complete Practice Quiz
3. Group Review

Introduction to arc flash

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