Electrical hazards 101

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(No Transcript)
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Electrical hazards 101

• Chris Matthewson
• Regional Compliance Assistance Specialist
• Denver, CO
• Phone [phone]
• VPPPA
• Denver Sheraton West

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Shock
TM
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Shock (Resistance Table)

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Shock

• mA Affect on Person
• 0.5 - 3 - Tingling sensations
• 3 - 10 - Muscle contractions and pain
• 10 - 40 - Let-go threshold
• 30 - 75 - Respiratory paralysis
• 100 - 200 - Ventricular fibrillation
• 200 - 500 - Heart clamps tight
• 1500 - Tissue and Organs start to burn

.0075 amps
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Flash Protection Boundary Burns
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Electrical Safety Statistics

• Average of 4,000 non-disabling and 3,600
  disabling electrical contact injuries annually in
  the United States
• One person is electrocuted in the workplace every
  day
• Electrocutions were the fourth leading cause of
  traumatic occupational fatalities.
• Over 2,000 workers are sent to burn centers each
  year with electrical-related burn injuries

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Arc Flash and Arc Blast
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Personnel Hazards Associated with Arc Flash

• Heat Burns Ignition of Materials
• Arc temperature of 35,000 ºF
• Molten metal, copper vapor, heated air
• Second Degree Burn Threshold
• 80 ºC / 175 ºF (0.1 sec), 2nd degree burn
• Third Degree Burn Threshold
• 96 ºC / 205 ºF (0.1 sec), 3rd degree burn
• Intense Light
• Damage eyes cataracts

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Second Degree Burn Threshold
Incident Energy
Measure of the thermal energy at a specific
distance from the arc flash. Units
calories per cm2

• 1.2 cal/cm2

Note medical treatment may still be required if
bare skin is exposed to this level of flash -
full recovery to be expected.
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Source American Burn Association (1991-1993
Study)
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Electrocution
What electrical hazard is responsible for nearly
80 of the accidents, incidents and fatalities
among Unqualified Workers?
Usually associated with a lack of equipment
grounding!
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Train your workers on electrical hazards!!!!!!
Who needs the training?
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Arc Blast / Arc Flash
80 of the electrically related accidents,
incidents, and fatalities among Qualified
Workers
is caused by?
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Reducing Arc Flash Exposure

• Deenergized

Incident energy
Time
Arc Flash Burn
Cycles
Amps
Distance
PPE
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Flash Protection Boundary Calculations
Test 4
Test 1
Test 3
26.7 in. 640 A Non Current-Limiting OCPD
6 cycles open
3.74 in. 601 A Current-Limiting OCPD
1.61 in. 30 A Current-Limiting OCPD
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Simulated Electric Arc Blast Untreated Cotton
Shirt ( 5.7 oz/yd2 )
Before Electric Arc Blast
During Electric Arc Blast
After Electric Arc Blast
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Simulated Electric Arc Blast NOMEX Workwear
(4.5 oz/yd2 )
Before Electric Arc Blast
During Electric Arc Blast
After Electric Arc Blast
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Electrical SafetyArc Flash Fire Resistant
Clothing
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Motor Control Center
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Working on or near live parts
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What's wrong with this picture?
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Installing or Removing draw-out devices may
require this level of PPE...
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Normal Conditions
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Abnormal Conditions
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Electrical Equipment
Deenergized

• Electrical Job at your plant
• What should be considered
• How to protect your workers
• Get everyone on board

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Beginning of an Electrical Accident
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Effects of the Incident
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Milwaukee
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Milwaukee (Continued)
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Summary

• 4 feet (at least)
• Work Deeneregized (prove it to me)
• Trouble Shooting allowed energized (PPE)
• Licensed-versus-Qualified
• Look at tools
• Follow assignment of work

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Qualified ?
Qualified ?
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Are these licensed electricians qualified?
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Thank you for your time

• Chris Matthewson
• Regional Compliance Assistance Specialist
• VPPPA Association
• Sheraton Denver West

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Disclaimer

• This information has been developed by an OSHA
  Compliance Assistance Specialist and is intended
  to assist employers, workers, and others as they
  strive to improve workplace health and safety.
  While we attempt to thoroughly address specific
  topics, it is not possible to include discussion
  of everything necessary to ensure a healthy and
  safe working environment in a presentation of
  this nature. Thus, this information must be
  understood as a tool for addressing workplace
  hazards, rather than an exhaustive statement of
  an employers legal obligations, which are
  defined by statute, regulations, and standards.
  Likewise, to the extent that this information
  references practices or procedures that may
  enhance health or safety, but which are not
  required by a statute, regulation, or standard,
  it cannot, and does not, create additional legal
  obligations. Finally, over time, OSHA may modify
  rules and interpretations in light of new
  technology, information, or circumstances to
  keep apprised of such developments, or to review
  information on a wide range of occupational
  safety and health topics, you can visit OSHAs
  website at www.osha.gov.