Hazards and Risks when working with Electricity

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Hazards and Riskswhen working withElectricity
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What is the best way to prevent the hazards of
electricity?

• Avoiding energized circuits is the safest way!

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STOP

• Think before taking
• Action

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THINK

• About the
• Risks and Hazards

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OPTIONS

• Do you have options like
• LOTO (Lockout/Tagout)

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PROTECTION

• Are you wearing PPE?
• (Personal Protective Equipment)

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What are theHazards and Risks?

1. Shock
2. Arc Flash Arc Blast
3. Fire Ignition

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SHOCK
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Shock and its Effects

• Immediate
• Muscle contraction
• Vital organs damaged
• Tingling
• Pain
• Breathing
• Disorientation
• Dizziness
• Possible death

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Shock and its Effects

• Long Term
• Memory Loss
• Nervous disorders
• Chemical imbalances
• Damage to vital organs
• Sometimes fatal

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Effect of Current on the Body

• MEN

• WOMEN

• Perception Threshold
• 0.001 Amps (1 mA)
• Painful Shock
• 0.009 Amps (9 mA)
• Cannot Let-Go Level
• 0.010 Amps (10 mA)
• Ventricular Fibrillation
• .100 Amps (100 mA)
• Heart Failure
• 0.5 Amps (500 mA)
• Organ Burn
• 1.5 Amps (1500 mA)

• Perception Threshold
• 0.0007 Amps (0.7 mA)
• Painful Shock
• 0.006 Amps (6 mA)
• Cannot Let-Go Level
• 0.010 Amps (10 mA)
• Ventricular Fibrillation
• .100 Amps (100 mA)
• Heart Failure
• 0.5 Amps (500 mA)
• Organ Burn
• 1.5 Amps (1500 mA)

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Two Types of burns from Shock

• Surface Burns
• Caused by entrance and exit of electrical
  currents through the body
• Can be caused by a very small amount of current
• 1st degree to 3rd degree

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Two Types of burns from Shock

• Internal Tissue Burns
• Caused by current flowing through organs of the
  body
• Caused by currents in excess of 1.5 amps
• 4th degree (internal)
• Internal organs
• Typically Fatal

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How to prevent Shock

• Place circuits in an Electrically Safe Working
  Condition by Locking Out and Tagging Out all
  sources.
• Verifying that no electrical energy is present.

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NFPA 70 - NEC

• The original and primary mission of the NFPA 70
  NEC covered installation of electrical systems.
• The NFPA 70 NEC does NOT address the other
  hazards of electricity.

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Exposure to Danger

• The NEC protects individuals from shock hazards
  under normal conditions.
• It is NOT designed to protect us from abnormal
  conditions.
• We need additional policies to protect from
  abnormal conditions.

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Normal Conditions

• Panel covers in place.
• Equipment plugged in normally.
• Normal designed protection in place.

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Abnormal Conditions

• Panel covers removed.
• Equipment temporarily wired.
• Normal designed protection such as guards, limits
  switches, etc. NOT in place.

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Protection fromAbnormal Conditions

• The Company
• NFPA 70E
• OSHA
• Electrical Safety Procedures Manual
• Electrical Safety Training

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Protection fromAbnormal Conditions

• YOU
• The first line of defense.
• Only you can truly keep you safe.
• Implement Safety Procedures Outlined in the
  Safety Manual.
• Only you can ensure that you go home at night.

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Arc FlashArc Blast
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Arc Flashis a high intensity flash which will
also create a very loud noise (blast).
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The Arc Flash produces

• Electric arc that produces the highest
  temperatures on earth up to 35,000oF (4 x temp.
  of the sun).
• The intense heat causes the sudden expansion of
  air that results in a blast.
• All known materials are vaporized at this
  temperature (copper expands 67,000 times, water
  1,670 times).

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Arc Flash BlastRelative to the human body

• A 2nd degree burn threshold, or a just curable
  burn threshold, is skin temperature raised to
  175oF for 0.1 second.
• A 3rd degree burn threshold, or incurable burn
  threshold, is skin temperature raised to 200oF
  for 0.1 second.
• Eardrum damage gt 720 psf
• Lung damage gt 1728 psf

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Arc Flash BlastRelative to the human body

• The hazard may be small for systems of less than
  300 volts with limited fault current.
• Any system over 300 volts probably has the
  capability to have significant arc flash event.

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Circuit Breaker Trips

• When a circuit has been de-energized by a
  protective device, DO NOT manually re-energize
  the circuit without first investigating the
  cause. Do not perform repetitive manual
  re-closing of breakers or replacing of fuses.

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Circuit Breaker Operation With Coverson and
voltages less than 600V ac rms

• Safety Glasses
• Natural Fiber Long Sleeve Shirt
• Natural Fiber Long Pants

Stand to the side
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Fused Switch Operation With Coverson and
voltages less than 600V ac rms

• Safety Glasses
• Natural Fiber Long Sleeve Shirt
• Natural Fiber Long Pants

Stand to the side
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FIRE IGNITION

• Clothing can be ignited several feet away unless
  flame resistant (FR) or arc rated (AR) clothing
  is worn.
• Note Synthetics burn into the skin when
  ignited.

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Clothing

• There is FR (flame resistant) clothing and AR
  (arc rated) clothing.
• ALL clothing with an arc rating (AR) is flame
  resistant (FR), but not all flame resistant
  clothing has an arc rating.

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Clothing

• Prior to 2015, untreated cotton was considered a
  safe fabric to wear.
• Beginning with the change to NFPA 70E in 2015,
  arc rated (AR) clothing is required as you will
  see later in this presentation.

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Now that you are aware of shock, arc flash and
arc blast, and fire ignition, what do you do
about it?
Protect Yourself
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Protect Yourself Against

1. Shock Hazard
2. Arc Flash and Arc Blast Hazard
3. Fire Ignition

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SHOCK Hazard

• What is required?
• Determine the Operating Voltage of the System.
• Determine Shock Protection Boundaries.
• Determine the Personal Protective Equipment.

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SHOCK Hazard

• Determine the Operating Voltage of the System.

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SHOCK Hazard

• Determine Shock Protection Boundaries.
• a. Limited Approach Boundary
• b. Restricted Approach Boundary

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Approach Boundaries
Limited Approach Boundary An approach limit
at a distance from an exposed energized
electrical conductor or circuit part within which
a shock hazard exists.
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Approach Boundaries
Restricted Approach Boundary An approach
limit at a distance from an exposed energized
electrical conductor or circuit part within which
there is an increased likelihood of electric
shock, due to electrical arc-over combined with
inadvertent movement, for personnel working in
close proximity to the energized electrical
conductor or circuit part.
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Approach Boundaries for Alternating Current
Systems
Limited Approach Boundary Fixed
Phase-to- Phase Voltage
Restricted Approach Boundary
Less than 50
Not specified
Not specified
Avoid contact
3 ft. 6 in.
50 150
1 ft. 0 in.
151 750
3 ft. 6 in.
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Qualified Person
One who has demonstrated skills and knowledge
related to the construction and operation of
electrical equipment and installations and has
received safety training to identify and avoid
the hazards involved.
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SHOCK Hazard
3. Determine the Personal Protective
Equipment. a. Use Voltage Rated (VR) Gloves
rated greater or equal to the voltage of the
system. b. Use Voltage Rated (VR) Tools rated
greater or equal to the voltage of the system.
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OSHA and NFPA 70E both state that qualified
electrical workers shall not be asked to work on
equipment that is hot or live except for two
demonstrable reasons
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1. De-energizing introduces additional or
increased hazards, like an emergency alarm
system or a ventilation system.
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2. Infeasible due to equipment design or
operational limitations, like voltage testing
for diagnostics or start up testing. Note
This is the HVACR trade.
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Conclusion
When you work on live circuits, you are open
to the hazards and risks of electricity.
Therefore, you need to take on the responsibility
of protecting yourself. So, how can this be done?
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NFPA 70E Hazard/Risk Categories

• Prior to 2015, NFPA 70E classified electrical
  hazards and risks from 0 to 4.
• In 2015, Category 0 was eliminated.
• The name Hazard/Risk was changed to Arc Flash
  PPE.

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Arc Flash PPEorIncident Energy AnalysisMethods
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How do you select the PPE?

• Prior to 2015, selection of PPE was based on
  Hazard/Risk Categories 0 4.
• In 2015, selection of PPE is based on either the
  Incident Energy Analysis Method or Arc Flash PPE
  Category Method, but not both.

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How do you select the PPE?

• The Arc Flash PPE Category Method is the simpler
  of the two and that is what this program will
  focus on.
• Before we look at the actual categories, lets
  take a look at some tasks and find where Arc
  Flash PPE is required.

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Table 130.7(C)(15)(A)(a) Arc Flash Identification
for Alternating Current (ac) and Direct Current
(dc) Systems
Arc Flash PPE Required
Task
Equipment Condition
Reading a panel meter operating a meter switch.
Any
No
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Table 130.7(C)(15)(A)(a) Arc Flash Identification
for Alternating Current (ac) and Direct Current
(dc) Systems
Arc Flash PPE Required
Task
Equipment Condition
Normal operation of a circuit breaker
(CB), switch, contactor, or starter
All of the following The equipment is properly
installed. The equipment is properly
maintained. All equipment doors are closed and
secured. All equipment covers are in place and
secured. There is no evidence of impending
failure.
No
One or more of the following The equipment is
NOT properly installed. The equipment is NOT
properly maintained. Equipment doors are open or
NOT secured. Equipment covers are off or NOT
secured. There is evidence of impending failure.
Yes
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Table 130.7(C)(15)(A)(a) Arc Flash Identification
for Alternating Current (ac) and Direct Current
(dc) Systems
Arc Flash PPE Required
Task
Equipment Condition
For Alternating Current systems work
on energized electrical conductors and
circuit parts, including voltage testing.
Any
Yes
Any
Removal or installation of CBs or switches.
Yes
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Table 130.7(C)(15)(A)(a) Arc Flash Identification
for Alternating Current (ac) and Direct Current
(dc) Systems
Arc Flash PPE Required
Task
Equipment Condition
Removal or installation of covers for
equipment such as wireways, junction boxes, and
cable trays that does not expose bare energized
electrical conductors and circuit parts.
All of the following The equipment is properly
installed. The equipment is properly
maintained. There is no evidence of impending
failure.
No
Any of the following The equipment is NOT
properly installed. The equipment is NOT properly
maintained. There is evidence of impending
failure.
Yes
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Table 130.7(C)(15)(A)(a) Arc Flash Identification
for Alternating Current (ac) and Direct Current
(dc) Systems
Arc Flash PPE Required
Task
Equipment Condition
Removal of bolted covers (to expose
bare energized electrical conductors and
circuit parts.)
Any
Yes
Opening hinged door(s) or cover(s) to expose
bare energized electrical conductors and
circuit parts.
Any
Yes
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Table 130.7(C)(15)(A)(a) Arc Flash Identification
for Alternating Current (ac) and Direct Current
(dc) Systems
Arc Flash PPE Required
Task
Equipment Condition
Work on control circuits with exposed
energized electrical conductors and circuit
parts, 120 volts or below without any
other exposed energized equipment over 120
V including opening of hinged covers to gain
access.
Any
No
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Table 130.7(C)(15)(A)(a) Arc Flash Identification
for Alternating Current (ac) and Direct Current
(dc) Systems
Arc Flash PPE Required
Task
Equipment Condition
Work on control circuits with exposed
energized electrical conductors and circuit
parts, greater than 120 V.
Any
Yes
Work on exposed energized electrical conductors
and circuit parts of equipment directly
supplied by a panelboard or motor control
center.
Any
Yes
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Table 130.7(C)(15)(A)(b) Arc-Flash Hazard PPE
Categories (Panelboards or other equipment rated
240 v and below)
Parameters Maximum of 25 kA short-circuit
current available Maximum of 0.03 sec (2 cycles)
fault clearing time Working distance 18
inches Arc Flash PPE Category 1 Arc Flash
Boundary 19 inches
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Table 130.7(C)(15)(A)(b) Arc-Flash Hazard PPE
Categories (Panelboards or other equipment rated
gt240 v and up to 600V)
Parameters Maximum of 25 kA short-circuit
current available Maximum of 0.03 sec (2 cycles)
fault clearing time Working distance 18
inches Arc Flash PPE Category 2 Arc Flash
Boundary 3 feet
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ARC FLASH BOUNDARY
The arc flash boundary shall be the distance at
which the incident energy equals 1.2 cal/cm2 Arc
Flash PPE Category 1 has a boundary of 19
inches. Arc Flash PPE Category 2 has a boundary
of 3 feet. What does this mean?
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Arc Flash Boundary is related to Incident
Energy.
Incident Energy cal/cm2
Degree Burn
1.2
2nd degree burn to bare skin
4
Ignite a cotton shirt
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3rd degree burn to skin
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Arc Flash Boundary is related to Incident
Energy. CONCLUSION
Incident Energy cal/cm2
PPE Category 1
PPE Category 2
Degree Burn
2nd degree burn to bare skin
1.2
19 inches
3 feet
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PPE Category 1

• Arc Rated Clothing, Minimum Arc Rating of 4
  cal/cm2
• Arc rated long sleeve shirt and pants or arc
  rated coverall
• Arc rated face shield or arc flash suit hood
• Arc rated jacket, parka, rainwear, or hard hat
  liner (AN)
• Protective Equipment
• Hard hat (for Industrial Workers)
• Safety glasses or safety goggles
• Hearing protection (ear canal inserts)
• Heavy duty leather gloves or combination of
  rubber insulating gloves with leather protectors
• Leather footwear (AN)

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PPE Category 2

• Arc Rated Clothing, Minimum Arc Rating of 8
  cal/cm2
• Arc rated long sleeve shirt and pants or arc
  rated coverall
• Arc rated face shield or arc flash suit hood and
  arc rated balaclava
• Arc rated jacket, parka, rainwear, or hard hat
  liner (AN)
• Protective Equipment
• Hard hat (for Industrial Workers)
• Safety glasses or safety goggles
• Hearing protection (ear canal inserts)
• Heavy duty leather gloves or combination of
  rubber insulating gloves with leather protectors
• Leather footwear (AN)

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Equipment Labeling
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Equipment Labeling
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Equipment Labeling
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GLOVES
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Class of Equipment Maximum Use Voltage (AC) Proof Tested (VAC) Proof Tested (VDC)
00 500 2,500 10,000
0 1,000 5,000 20,000
1 7,500 10,000 40,000
2 17,000 20,000 50,000
3 26,500 30,000 60,000
4 36,000 40,000 70,000
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Meter Requirements CAT III or CAT IV
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Who is Responsible for Electrical Safety?

• Employers are required to
• Select appropriate PPE based on the hazards
  present or likely to be present in the workplace.
• Prohibit the use of defective or damaged PPE.
• Require that employees be trained so that each
  affected employee can properly use the assigned
  PPE.

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NFPA 70E Enforcement
The practical result of complying with the safe
work practices defined in NFPA 70E is, in most
cases, complying also with the applicable OSHA
regulations.
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NFPA 70E Enforcement
Compliance is not mandatory, so OSHA safety and
health compliance officers do not enforce NFPA
70E per se. But you can be cited for not
complying with the standard. There is a growing
tendency for them to rely on NFPA 70E under the
so-called general duty clause.
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NFPA 70E Enforcement
The OSHA general duty clause as found in
Section 5 (a)(1) of the Occupational Safety and
Health Act requires employers to furnish safe
workplaces that are free from recognized hazards
that are causing, or are likely to cause, death
or serious physical harm to employees.
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Responseto anElectrical Accident
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Response to an Electrical Accident

1. The first step must be to TURN THE POWER
   OFF
2. Remember that Speed is Essential
3. Extinguish flames
4. Call for Help (911)
5. Begin CPR First Aid

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Response to an Electrical Accident

• First Aid
• a. Cool the burn with water.
• Do not attempt to remove burned clothing.
• Elevate burned limbs.
• Handle the victim with care.
• Treat for shock.

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Conclusion
When you work on live circuits, you are open
to the hazards and risks of electricity.
Therefore, you need to take on the responsibility
of protecting yourself.
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VIDEOS
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SHORTED20kA circuit100 AmpDisconnect
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Switch GearExplosionPlease watch carefully as
to when the worker puts his face shielddown and
the explosion.
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Switch GearExplosionThere are 3 workers.
Watch for the one that is squatting between the
other 2 during the explosion.The camera on the
roof saw it all.
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Breaker Disconnecton Roof
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• What are some things he could have done to better
  protect himself?

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Tech Electrocuted Changing Air Filter

1. Heat Pump Service Call.
2. Checked out the equipment in the attic and
   outside.
3. Went under the house to change the air filter.
4. Touched the air handler cabinet, became locked
   and grounded by a wire that was shorted to the
   air handlers metal cabinet.

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Tech Electrocuted Changing Air Filter

• 5. He was LOCKED to the air handler and after
  some 15 minutes the homeowner called him.
• When he did not answer, the owner went under and
  found him and was able to knock him off the unit
  and freed him.
• The owner dragged him out and started CPR.
• EMS arrived and continued CPR on the way to the
  Medical Center, where medical staff continued
  CPR, but a doctor pronounced him dead.

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Tech Electrocuted Changing Air Filter

• What are some things he could have done to better
  protect himself?

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A novel way of taking a selfie that ended badly.
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YOU need to RESPECT electricity andBE SAFE.
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Thats All Folks