safety electricity
Transcript of safety electricity
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Electricity
The Dangers
About 5 workers areelectrocuted every week
Causes 12% of young
worker workplace deaths Takes very little
electricity to cause harm
Significant risk of causingfires
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Electricity How it Works
Electricity is the flow ofenergy from one place toanother
Requires a source of power:usually a generating station
A flow of electrons (current)travels through a conductor
Travels in a closed circuit
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Electrical Injuries
There are two main types of electrical injuries: Direct:
Electrocution or death due to electrical shock
Burns / Flash: When heat from a nearby electrical arc causes
thermal burns The temperature of an electrical arc can reach 2500-
5000o C
Electrical arcs
Indirect - Falls
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Electrical Shock
An electrical shock is received when electrical
current passes through the body.
You will get an electrical shock if a part of yourbody completes an electrical circuit by
Touching a live wire and an electrical ground, or
Touching a live wire and another wire at a
different voltage.
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Shock Severity
Severity of the shock depends on:
Path of current through thebody
Amount of current flowingthrough the body (amps)
Duration of the shockingcurrent through the body,
LOW VOLTAGE DOES NOTMEAN LOW HAZARD
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Dangers of Electrical Shock
Currents above 10 mA* canparalyze or freeze muscles.
Currents more than 75 mA cancause ineffective heartbeat --
death will occur in a few minutesunless a defibrillator is used
a small power drill uses 30 timesas much
* mA = milliampere = 1/1,000 of an ampere
Defibrillator in use
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Burns
Most common shock-relatedinjury
Occurs when you touchelectrical wiring or equipment
that is improperly used ormaintained
Typically occurs on hands
Very serious injury thatneeds immediate attention
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Falls
Electric shock can alsocause indirect injuries
Workers in elevatedlocations who experiencea shock may fall,resulting in serious injuryor death
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Electrical Hazards and How to
Control Them
Electrical accidents arecaused by a combination
of three factors:Unsafe equipment
and/or installation,
Workplaces made
unsafe by theenvironment, and
Unsafe work practices.
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Hazard Overloaded Circuits
Hazards may result from: Too many devices plugged
into a circuit, causing heatedwires and possibly a fire
Damaged tools overheating Lack of overcurrent
protection
Wire insulation melting, whichmay cause arcing and a fire in
the area where the overloadexists, even inside a wall
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Clues that Electrical Hazards Exist
Tripped circuit breakers orblown fuses
Warm tools, wires, cords,connections, or junctionboxes
Damaged insulation aroundwire or connection
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Safety-Related Work Practices
To protect workers from electrical shock:
Use barriers and guards to preventpassage through areas of exposedenergized equipment
Pre-plan work, post hazard warningsand use protective measures
Keep working spaces and walkwaysclear of cords
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Safety-Related Work Practices
Use special insulated tools
when working on fuses with
energized terminals
Dont use bad cords and
cables
Dont fasten extension cords
with staples, hang from nails,
or suspend by wire.
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Preventing Electrical Hazards -
Planning
Plan your work with others
Plan to avoid falls
Plan to lock-out and tag-out equipment
Remove jewelry
Avoid wet conditions andoverhead power lines
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Avoid Wet Conditions
If you touch a live wire or otherelectrical component while standingin even a small puddle of water youllget a shock.
Damaged insulation, equipment, or
tools can expose you to liveelectrical parts.
Improperly grounded metal switchplates & ceiling lights are especiallyhazardous in wet conditions.
Wet clothing, high humidity, andperspiration increase your chancesof being electrocuted.
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Grounding
Grounding creates a low-
resistance path from a tool
to the earth to disperse
unwanted current.
When a short or lightning
occurs, energy flows to the
ground, protecting you
from electrical shock,
injury and death.
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Preventing Electrical Hazards
Proper foot protection(not tennis shoes)
Rubber insulatinggloves, hoods, sleeves,matting, and blankets
Hard hat (insulated
nonconductive notuniform hat)
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Summary
Electrical equipment must be:
Listed and labeled (good quality)
Free from hazards
Used in right wayIf you use electrical tools you must be:
Protected from electrical shock
Provided necessary safety equipment
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