Transcript Slide No. 6 Common Electrical Hazards In Industries What is

Common Electrical Hazards In Industries
Slide No. 1
Common Electrical Hazards In Industries
Common Electrical Hazards In
Industries
Presented By
Engr. Azfar A.Kaim Khani
Slide No. 2
Common Electrical Hazards In Industries
Electrical Terminology
•Power
Amount of energy used each second, measured in
watts
•Current
The movement of electrical charge
• Resistance
Opposition to current flow
• voltage
Measure of electrical force
• Risk
Chance that injury or death will occur
• Shocking current
Electrical current that passes through a part of the body
Slide No. 3
Common Electrical Hazards In Industries
Electrical Terminology Continued…
• Over-current protection device
Device that prevents too much current in a circuit
• Qualified person
Someone who has received mandated training on the
hazards and on the
construction and operation of
equipment involved in a task
• Insulators
Substances, such as wood, rubber and glass that have
high resistance to electricity
• Grounding
A conductive connection to the earth which acts as a
protective measure
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Common Electrical Hazards In Industries
Electrical Terminology Continued…
• Short Circuit
Low-resistance path between a live wire and the
ground, or between wires at different voltages
(called a fault if the current is unintended)
• tag-out
Applying a tag that alerts workers that circuits and
equipment have been locked out
• trip
Automatic opening (turning off) of a circuit by a
GFCI or circuit breaker
Slide No. 5
Common Electrical Hazards In Industries
What is Electricity & how does it works
Power in Electrical Circuit is:
P=VxI
Voltage [driving force] causes current to flow
Current [flow of Electrons]
Circuit / loop is necessary for current to flow
Slide No. 6
Common Electrical Hazards In Industries
Circuit / loop is necessary for
current to flow
Slide No. 7
Common Electrical Hazards In Industries
Electrical Injuries
There are four main types of electrical injuries:
• Direct:
Electrocution or death due to electrical shock
Electrical shock
Burns
• Indirect - Falls
Slide No. 8
Common Electrical Hazards In Industries
Hazard - Overhead Power Lines
usually not insulated
• Examples of equipment that
can contact power lines:
– Crane
– Ladder
– Scaffold
– Scissors lift
– Raised dump truck bed
Slide No. 9
Common Electrical Hazards In Industries
Control - Overhead Power Lines
• Stay at least 10 feet away
• Post warning signs
• Assume that lines are
energized
• Use wood or fiberglass
ladders, not metal
• Power line workers need
special training & PPE
Slide No. 10
Common Electrical Hazards In Industries
Injury to a person may be in the
form of:
•
•
•
•
Electric Shock
Burns
Fire
Eye Injuries
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Common Electrical Hazards In Industries
Electrical Shock
• Received when current passes
through the body
• Severity of the shock depends
on:
– Path of current through the
body
– Amount of current flowing
through the body
– Length of time the body is in
the circuit
Slide No. 12
Common Electrical Hazards In Industries
Dangers of Electrical Shock
• Currents above 10 mA* can
paralyze or “freeze” muscles.
• Currents more than 75 mA can
cause a rapid, ineffective heartbeat,
death will occur in a few minutes
unless a defibrillator is used
• 75 mA is not much current – a small
power drill uses 30 times as much
Defibrillator in use
* mA = milliamp ere = 1/1,000 of an ampere
Slide No. 13
Common Electrical Hazards In Industries
Electrical Burns
• Most common shockrelated, nonfatal injury
• Occurs when you touch live
electrical wiring or
equipment that is
improperly used or
maintained
• Typically occurs on the
hands.
• Very serious injury that
needs immediate attention
Slide No. 14
Common Electrical Hazards In Industries
Falls
• Electric shock can also
cause indirect injuries
• Workers
in
elevated
locations who experience a
shock may fall, resulting in
serious injury or death
Slide No. 15
Common Electrical Hazards In Industries
How is an electrical shock received?
• When two wires have different potential differences
(voltages), current will flow if they are connected
together.
– In most household wiring, the black wires are at zero
volts because they are neutral.
– The red wires are at 220 volts ( For Single Phase
relative to ground).
– If some one come into contact with an energized
(live) red wire, and also in contact with the black
neutral wire, current will pass through the body and
WILL RECEIVE AN ELECTRIC SHOCK
Slide No. 16
Common Electrical Hazards In Industries
FIRE
• There has been a series of fire
incidents in many multistory
buildings
and
industries
in
Pakistan.
Results
of
these
incidents at some of the places
have been devastating, destroying
whole building or industry. The
most common cause of fire
analyzed
for
these
horrible
incidents is short circuiting.
Slide No. 17
Common Electrical Hazards In Industries
Electric Short Circuit
Low-resistance path between a live wire and the
ground, or between wires at different voltages)
In a short circuit, current passes
through the shorting material without
passing through a load in the circuit,
and the wire becomes overheated.
Slide No. 18
Common Electrical Hazards In Industries
Reasons For Short Circuit
• There may be a number of reasons for electric
short circuit; however, wiring with defects such as
insulation failure, overloaded conductors and
poor connections are found to play major role in
this. Other fires are attributed to equipment such
as electric motors, heaters, lighting and cooking
appliances.
•
The heat generated by loose connection can be
sufficient to ignite flammable material, liquid or
gas and hence may cause catastrophic fires and
explosions.
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Common Electrical Hazards In Industries
Overload Conductor
• If too many devices are
plugged into a circuit, the
current will heat the wires
to a very high temperature,
which may cause a fire
• If the wire insulation melts,
it can cause a fire in the
area where the overload
exists, even inside a wall
Slide No. 20
Common Electrical Hazards In Industries
Electrical Hazards and How to
Control Them
• Electrical accidents are
caused by a combination of
three factors:
– Unsafe equipment and/or
installation,
– Workplaces made unsafe by
the environment, and
– Unsafe work practices.
Slide No. 21
Common Electrical Hazards In Industries
Hazard – Exposed Electrical Parts
Cover removed from wiring or breaker box
Slide No. 22
Common Electrical Hazards In Industries
Control – Isolate Electrical Parts
• Use guards or
barriers
• Replace covers
Guard live parts of electric
equipment operating at 50 volts or
more against accidental contact
Slide No. 23
Common Electrical Hazards In Industries
Control – Isolate Electrical Parts Cabinets, Boxes & Fittings
Conductors going into them must be protected, and unused
openings must be closed
Slide No. 24
Common Electrical Hazards In Industries
Control – Close Openings
• Junction boxes, pull
boxes and fittings must
have approved covers
• Unused openings in
cabinets, boxes and
fittings must be closed
Photo shows violations
of these two requirements
Slide No. 25
Common Electrical Hazards In Industries
Grounding Hazards
Some of the most common violations
• Metal parts of an electrical wiring system that we touch
(switch plates, ceiling light fixtures, conduit, etc.) should
be at zero volts relative to ground
• Housings of motors, appliances or tools that are
plugged into improperly grounded circuits may become
energized
• If some one come into contact with an improperly
grounded electrical device, CAN BE SHOCKED
Slide No. 26
Common Electrical Hazards In Industries
Safety Management System
• Since every process in an industry involves electricity,
it is therefore not possible to prevent employees from
electrical related incidents without implementing a
proper safety management system.
Job Hazard Analysis
• A job hazard analysis, also called a job safety
analysis is an organized approach that involves the
worker and supervisor observing a task, breaking it
down into steps. Each step is then analyzed for
safety and operational needs.
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Common Electrical Hazards In Industries
DEFFINITIONS
• NEAR MISS:
A Near miss describes incident where
no property was damaged and no personal Injury
sustained, but when a given a slight shift in time or
position, damage and / or injury easily could have
occurred.
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Common Electrical Hazards In Industries
DEFFINITIONS
• INCIDENT:An incident is an unplanned, un desired
event that adversely affects the completion of a task
• ACCIDENT:National Safety Council defines an
Accident as an undesired event that results in
personal injury or property damage
Incident/Accident Analysis
• All non-injury incidents and injury accidents, even
a minor electrical shock should be analyzed.
Incidents analysis allows identifying and
controlling hazards before they cause an injury.
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Common Electrical Hazards In Industries
Safe Working Practices
• Personnel involved in electrical work have
often to deal with live working situations. It
is therefore necessary to set such rules,
which govern overall working activities.
Only competent persons (who possess
certificate,sufficient technical knowledge,
experience and skill) should be given any
task.
Slide No. 30
Common Electrical Hazards In Industries
Proper Grounding of Equipments
• Grounding is connecting an electrical system to the
earth with a wire. Excess or stray current travels
through this wire to a grounding device (commonly
called a “ground”) deep in the earth. Grounding
prevents unwanted voltage on electrical components.
Grounding creates a path for currents produced by
unintended voltages on exposed parts. These
currents follow the grounding path, rather than
passing through the body of someone who touches
the energized equipment.
Slide No. 31
Common Electrical Hazards In Industries
Equipment needs to be grounded
under any of these circumstances:
• The equipment is within 8 feet vertically and 5
feet horizontally of the floor or walking surface.
• The equipment is within 8 feet vertically and 5
feet horizontally of grounded metal objects you
could touch.
• The equipment is located in a wet or damp area
and is not isolated.
• The equipment is connected to a power supply by
cord and plug and is not double-insulated.
Slide No. 32
Common Electrical Hazards In Industries
Electrical Protective Devices
• These devices shut off electricity flow
automatically in the event of an overload or
ground-fault in the circuit
• Include fuses, circuit breakers, and groundfault circuit-interrupters (GFCI’s). Fuses and
circuit breakers are over current devices
– When there is too much current:
• Fuses melt
• Circuit breakers trip/ open
Slide No. 33
Common Electrical Hazards In Industries
The NEC requires that GFCI’s be
used in these high-risk situations:
• Electricity is used near water.
• The user of electrical equipment is
grounded (by touching grounded material).
• Circuits are providing power to portable
tools or outdoor receptacles.
• Temporary wiring or extension cords are
used.
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Common Electrical Hazards In Industries
Grounding Path
• The path to ground from
circuits,
equipment,
and
enclosures
must
be
permanent and continuous
• Violation shown here is an
extension cord with a missing
grounding prong
Slide No. 35
Common Electrical Hazards In Industries
Hand-Held Electric Tools
• Hand-held electric tools pose a
potential danger because they make
continuous good contact with the hand
• To protect you from shock, burns, and
electrocution, tools must:
– Have a three-wire cord with ground
and be plugged into a grounded
receptacle, or
– Be double insulated.
Slide No. 36
Common Electrical Hazards In Industries
Guarding of Live Parts
• Must guard live parts of electric
equipment operating at 50 volts or
more against accidental contact by:
– Approved cabinets/enclosures, or
– Location or permanent partitions
making them accessible only to
qualified persons, or
– Elevation of 8 ft. or more above the
floor or working surface
• Mark entrances to guarded locations
with conspicuous warning signs
Slide No. 37
Common Electrical Hazards In Industries
Guarding of Live Parts (cont’d)
• Must enclose or guard
electric equipment in
locations where it would
be exposed to physical
damage
• Violation shown here is
physical damage to
conduit
Slide No. 38
Common Electrical Hazards In Industries
Use of Flexible Cords
• More vulnerable than fixed wiring
• Do not use if one of the recognized
wiring methods can be used
instead
• Flexible cords can be damaged by:
– Aging
– Door or window edges
– Staples or fastenings
– Abrasion from adjacent
materials
– Activities in the area
• Improper use of flexible cords can
cause shocks, burns or fire
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Common Electrical Hazards In Industries
Permissible Uses of Flexible Cords
Examples
Pendant, or
Fixture Wiring
Portable lamps,
tools or appliances
Stationary equipmentto facilitate interchange
Slide No. 40
Common Electrical Hazards In Industries
Prohibited Uses of Flexible Cords
Examples
Substitute for
fixed wiring
Run through walls,
ceilings, floors,
doors, or windows
Slide No. 41
Common Electrical Hazards In Industries
Tool Safety Tips
•
•
•
•
•
•
•
•
Use gloves and appropriate footwear
Store in dry place when not using
Don’t use in wet/damp conditions
Keep working areas well lit
Ensure not a tripping hazard
Don’t carry a tool by the cord
Don’t yank the cord to disconnect it
Keep cords away from heat, oil, & sharp
edges
• Disconnect when not in use and when
changing accessories such as blades & bits
• Remove damaged tools from use
Slide No. 42
Common Electrical Hazards In Industries
Clues that Electrical Hazards Exist
• Tripped circuit breakers or blown fuses
• Warm tools, wires, cords, connections,
or junction boxes
• GFCI that shuts off a circuit
• Worn or frayed insulation around wire or
connection
Slide No. 43
Common Electrical Hazards In Industries
Lockout and Tagging of Circuits
• Apply locks to power source after
de-energizing
• Tag deactivated controls
• Tag de-energized equipment and
circuits at all points where they
can be energized
• Tags must identify equipment or
circuits being worked on
Slide No. 44
Common Electrical Hazards In Industries
Safety-Related Work Practices
• Use special insulated tools
when working on fuses
with energized terminals
• Don’t use worn or frayed
cords and cables
• Don’t fasten extension
cords with staples, hang
from nails, or suspend by
wire.
Slide No. 45
Common Electrical Hazards In Industries
Preventing Electrical Hazards Planning
• Plan your work with others
• Plan to avoid falls
• Plan to lock-out and tagout equipment
• Remove jewelry/ rings
• Avoid wet conditions and
overhead power lines
Slide No. 46
Common Electrical Hazards In Industries
Avoid Wet Conditions
• If you touch a live wire or other
electrical component while standing in
even a small puddle of water you’ll get
a shock.
• Damaged insulation, equipment, or
tools can expose you to live electrical
parts.
• Improperly grounded metal switch
plates & ceiling lights are especially
hazardous in wet conditions.
• Wet clothing and high humidity
increase
chances
of
being
electrocuted.
Slide No. 47
Common Electrical Hazards In Industries
Preventing Electrical Hazards - PPE
• Proper foot protection
(not tennis shoes)
• Rubber
insulating
gloves, hoods, sleeves,
matting, and blankets
• Hard hat (insulated nonconductive)
• Face shield
Slide No. 48
Common Electrical Hazards In Industries
Training
Train employees working with electric
equipment in safe work practices, including:
• Deenergize electric equipment before
inspecting or repairing
• Using cords, cables, and electric tools that
are in good condition
• Lockout / Tagout recognition and procedures
• Use appropriate protective equipment
Slide No. 49
Common Electrical Hazards In Industries
Slide No. 50
Common Electrical Hazards In Industries
THANK YOU
Slide No. 51