Transcript ElectricalSafetyx

Electrical Safety & LOTO
Awareness Training
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Overview
• We all use equipment and deal with
electricity, and must be intimately
involved in this process
• All parts of the
electrical puzzle
must fit together
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Statistics
• Over 6,000 work-related deaths occur
each year in workplaces employing 11
workers or more
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• Six percent of the fatalities, or around
347 deaths, were the direct result of
electrocutions at work
These fatalities could have been easily
avoided.
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How Electricity Works
• Operating an electric switch is like turning on
a water faucet.
• Water = the source pumped through pipes;
the force to make it flow is pressure, provided
by a pump
• For electricity = the source current, travels
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through electric conductors by pressure,
measured in volts, provided by a generator
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Resistance
Resistance to the flow of electricity is
measured in ohms and varies
widely. It is determined by 3 factors:
• The nature of the substance itself
• The length and cross-sectional area
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(size) of the substance
• The temperature of the substance
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Insulators/Conductors
• Metals offer very little resistance –
called conductors
• Other substances - bakelite, porcelain,
pottery, and dry wood, offer high
resistance – prevent the flow of current
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- called insulators
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Insulators/Conductors
• Pure water is a poor conductor, but
small amounts of impurities, such
as salt and acid (both of which are
contained in perspiration), make it
a ready conductor
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• When water is present either in the
environment or on the skin, anyone
working with electricity should
exercise even more caution than
they normally would
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How Shock Occurs
The severity of the shock received is affected by three
primary factors:
• The amount of current flowing through the body
(measured in amperes)
• The path of the current through the body
• The length of time the body is in the circuit
Other factors that may affect the severity of shock
are the:
• Frequency of the current;
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Phase of the heart cycle when
shock occurs
• General health of the person
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Shock & the Human Body
• The effects of electric shock depend upon the
type of circuit, its voltage, resistance, current,
pathway through the body, and duration of the
contact
• Effects can range from a barely perceptible
tingle to immediate cardiac arrest
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• There are no absolute limits or even known
values that show the exact injury from any
given current
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Shock & the Human Body
• The so-called low voltages can
be extremely dangerous
• Degree of injury is proportional
to the length of time the body
is in the circuit
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LOW VOLTAGE DOES
NOT IMPLY LOW HAZARD!
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Shock & the Human Body
•
A severe shock can cause:
1. internal hemorrhages
2. destruction of tissues, nerves, and
muscles
•
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•
Shock is often only the beginning
in a chain of events
The final injury may well be from a
fall, cuts, burns, or broken bones
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Shock & the Human Body
Current/Reaction:
• 1 Milliampere / Perception level. Just a faint
tingle
• 5 Milliamperes / Slight shock felt; not painful but
disturbing - average individual can let go.
However, strong involuntary reactions to shocks
in this range can lead to injuries
• 6-25 Milliamperes (women) / Painful shock,
muscular control is lost
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• 9-30 Milliamperes (men) / This is called the
freezing current or “let-go" range
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Shock & the Human Body
Current/Reaction:
• 50-150 Milliamperes / Extreme pain, respiratory
arrest, severe muscular contractions*
Individual cannot let go. Death is possible
• 1,000-4,300 Milliamperes Ventricular fibrillation.
(The rhythmic pumping action of the heart
ceases.) Muscular contraction and nerve
damage occur. Death is most likely
• 10,000-Milliamperes Cardiac arrest, severe
burns and probable death
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Burns & Other Injuries
The most common shock-related
injury is a burn. Burns suffered in
electrical accidents may be of three
types:
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• Electrical
• Arc
• Thermal contact
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Burns & Other Injuries
• Electrical burns are the result of the
electric current flowing through tissues or
bone
• Tissue damage is caused by the heat
generated by the current flow through the
body
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• Electrical burns are one of the most
serious injuries you can receive and
should be given immediate attention
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Burns & Other Injuries
• Arc or flash burns, on the other hand, are
the result of high temperatures near the
body and are produced by an electric arc
or explosion
• They should also be
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attended to promptly
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Burns & Other Injuries
• Thermal contact burns are those normally
experienced when the skin comes in contact
with hot surfaces of overheated electric
conductors, conduits, or other energized
equipment
• Additionally, clothing may be ignited in an
electrical accident and a thermal burn will result
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• All three types of burns may be produced
simultaneously
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Preventing Electrical Hazards
•
Electrical accidents - three possible factors:
1. unsafe equipment and/or installation
2. workplaces unsafe by environment
3. unsafe work practices
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There are various ways of protecting people
from the hazards caused by electricity
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•
These include: insulation; guarding;
grounding; electrical protective devices; and
safe work practices
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Prevention of Electrical Hazards
These include:
• Insulation
• Guarding
• Grounding
• Electrical protective
devices
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• Safe work practices
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Insulation
• One way to safeguard individuals
from electrically energized wires
and parts is through insulation
• An insulator is any material
with high resistance to
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electric current
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Guarding
Live parts of electric equipment
operating at 50 volts or more must be
guarded against accidental contact. This
is accomplished by:
• Location
• Permanent partitions
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• Elevation of 8 feet (2.44 meters) or more
above the floor
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Guarding
• Mark entrances to rooms and other
guarded locations containing exposed
live parts with warning signs
• Indoor electric wiring of more than
600 volts, must be controlled by a lock
• In addition, equipment must be marked
with appropriate caution signs
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Grounding
• Two kinds of required grounds
• One of these is called the "service or system
ground“
• One wire-called "the neutral conductor" or
"grounded conductor" is grounded at the
generator or transformer and again at
the service entrance of the building
• This type of ground is primarily
designed to protect machines, tools,
and insulation against damage
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Circuit Protection Devices
EXTREMELY IMPORTANT
• Never remove a grounding device from any
electrical source, tool, or equipment
• Never remove the ground prong from an
electrical cord or device of any kind
• Never by-pass grounding or circuit breaker
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• If you find any of the above have occurred, repair
and/or report immediately
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Circuit Protection Devices
• Circuit protection devices are designed to
automatically limit or shut off the flow of
electricity in the event of a ground-fault,
overload, or short circuit in the wiring system
• Fuses, circuit breakers, and ground-fault
circuit interrupters are three well-known
examples
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Circuit Protection Devices
• Fuses and circuit breakers are intended
primarily for the protection of conductors and
equipment
• They prevent over-heating of wires and
components that might otherwise create
hazards for operators
• They also open the circuit under certain
hazardous ground-fault conditions
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Safe Work Practices
Employees and others working with electric
equipment need to use safe work practices.
These include:
• Deenergizing electric equipment before inspecting
or making repairs
• Using electric tools that are in good repair; using
good judgment when working near
energized lines
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Using appropriate protective equipment
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Lock-out/Tag-out
Electrical Policy:
• Electrical panels must be manned at all times
while open and or being worked on
• With the exception of when work is being
performed on or in electrical panels, and the
electrical panels are manned, all electrical
panels must be closed at all times
• Prior to any work being performed on an
electrical panel, the power to the panel must be
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turned off, and checked to make sure the power
is off
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Lock-out/Tag-out
• When a problem with a breaker occurs in an electrical
panel, make sure the breaker is in the off position
• Place electrical tape (no other tape is allowed), over the
breaker - do not allow the breaker to be turned on
without removal of the tape
• Close the panel box
• Lock the panel cover if that feature is available
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• Place a sign on the panel door noting the problem, the
breaker number, and clearly indicate that the panel box
is not to be opened by anyone but authorized and
qualified repair personnel
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Lock-out/Tag-out
• Be sure the sign is attached to the cover so it cannot fall off
• It must be physically removed. Attach the electrical lock-out
tag to the panel cover in addition to the sign
• Unless you are the qualified district electrician, this lock-out
must not be removed or tampered with
• Lock any additional doors to the equipment, i.e. vault room,
and place sign on the door indicating “No Admittance –
Electrical Work in progress – Danger”
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Lock-out/Tag-out
• In any electrical panel or breaker problem, report the
problem to the site administrator, the custodial staff on all
shifts, and the maintenance department
• In the case of a non-emergency, a standard on-line work
order can be used to notify the maintenance department
• In the case of an emergency or urgent problem, call the
maintenance department director for assistance and
notification
• In all cases, follow-up with an on-line work order and
document the problem with dates, times, and names
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Lock-out/Tag-out
• For faulty electrical with powered equipment, disconnect
the power to the unit completely by turning off the
breaker, and disconnecting the power cord if possible
• Place a sign in the same manner as the panel
box above
• Also state the problem with the unit if know and
any hazards such as potential electrical shock. Install
the lock-out tag on the power ‘on’ switch and tape the
switch in the off position with electrical tape
• Inform essential personnel and staff that use the
equipment
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Lock-out/Tag-out
• The lock-out tag must include certain
information. This includes the name of
the person installing the tag
• This tag can only be removed
by the person originally
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installing it or a qualified
electrician
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Lock-out/Tag-out
The removed tag must be returned to the
office and saved in a file that contains an
explanation of:
• The electrical problem
• How the problem was handled
• Who found the problem
• Who installed the lock-out tag
• Who reported the problem
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• Who repaired the problem
• Who removed the lock-out tag
• This is best served in an on-going report on
the problem. Documentation is everything
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Lock-out/Tag-out
What Documentation Does:
• Gives you a great resource to follow-up
• Provides compliance with regulations
• Instills a sense of completion to a problem
• Provides exacting steps that need to be done
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as long as the file is open
• Provides information for future reference
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Lock-out/Tag-out
What Timely Reporting Does:
• Puts the people who need to fix the problem
on notice.
• Provides you with the right information when
asked
• Follows the proper regulations and guidelines
• Offers
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the repair people the opportunity to get
to the problem quicker
• Allows the problem to be taken care of faster
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Lock-out/Tag-out
• The same procedure for electrical
panels must be followed for all
mechanical equipment, and machinery
• Lock-out/Tag-out procedures include:
– Air handlers
– Floor cleaning machines
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– Vehicles, fork lifts, and all other equipment
that is either motorized, pinches, grabs, lifts,
– Or equipment that moves or operates by a
power source or under it’s own power
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Care of Cords & Equipment
• Electric panels must be kept clear of any
obstructions at all times
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• Storage is not allowed in electrical vault or
service panel rooms. Find another place for
storage of materials, products, etc
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Summary
• Electricity can be helpful and also dangerous, if not
respected
• Safety procedures must be followed in order to protect
everyone when dealing with electrical
• Lock-out/Tag-out procedures for electrical must be
followed to help ensure safety and regulatory compliance
• Lock-out/Tag-out includes other equipment besides
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electrical and must have the same reporting and
documentation
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