Transcript Electrical Safety - the Mining Quiz List

Electrical SafetyRelated Work
Practices
In and around the mines
AND
The home
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Jon Montgomery, EFS
[email protected]
 Albany, NY
 518-489-0780
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WHAT IS ELECTRICITY??
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?
 Electricity is a form of energy
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High Voltage (>650 volts)
Low Voltage (650 volts or less)
Alternating Current
Direct Current
Static Electricity
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ELECTRICAL ACCIDENTS
 Electrocutions rank fourth in work related
fatalities with about half of these at 600
volts or less.
 There are an average of over 3,600
disabling electrical related injuries
annually.
 There are an average of 4,000 non-
disabling electrical injuries annually.
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Let’s talk about personal protection and the home
40,000 residential fires annually which are caused by
problems with electrical wiring systems, claiming more
than 350 lives
Additionally, electric cords and plugs were involved in
about 7,100 fires resulting in 120 deaths or about 32%
of all deaths associated with residential electrical
system fires, occurring each year.
Lamps and light fixtures were involved in about 8,900 fires
and 60 deaths
About 3,600 people are treated for injuries associated with
extension cords.
Switches and outlets are involved in 4,700 fires and deaths
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Reported Mining Electrical Accidents
(INCLUDES FATALITIES)
1990 thru 2000
 Coal-Underground
752
137
 Coal-Surface
 Metal/non-metal-Underground
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 Metal/non-metal-Surface
 Prep Plants
 Other
Total
655
244
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1921
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Fatal Electrical Accidents
1990 thru 2000
But more important is the cost in lives……
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Coal-Underground
Coal-Surface
Metal/non-metal-Underground
Metal/non-metal-Surface
Prep Plants
Other
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7
29
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Total
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Causes of Electrical Injuries
 Touching live parts.
Short circuit
Accidental ground
Overload
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Electrical Hazards
 Exposed conductors
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Frayed and worn insulation
Exposed bus bars and connections
 Overloaded circuits
 Modified circuits
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Removed grounding plug
Jury-rigged connections
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Effects on the Body
 Burns
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Flash burns (from electrical arcs)
Electrical burns (entry & exit wounds)
 Electrical Shock
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Damage to internal organs and body
systems
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Effects on the Body
 Approximately 50 volts is needed to
overcome skin resistance
Resistance is higher on dry skin
Resistance is lower on wet skin
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ENTRY WOUND
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EXIT WOUND
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Electrical Shock
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A person receives an electrical shock whenever any
part of his/her body becomes part of the electrical
circuit through which a sufficient current flows to cause
discomfort or worse.
 Current flow slightly above this threshold is sufficient
to cause discomfort:
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May cause involuntary contraction of the muscles.
Stop the heart.
Stop breathing.
Cause burns.
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Electrical Shock
 The amount of current that flows through the
victim’s body will depend on:
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The voltage of the circuit with which he/she is in
contact.
The insulating qualities of the place in which
he/she is located at the instant.
The resistance of skin or clothing or both.
 The area of contact with the live conductor.
 The pressure of contact with the live conductor.
 The area of contact with the live conductor
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four major components of an
electrical system
sources
conductors
loads
switches
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SOURCES
provide electricity
 batteries
 transformers
 generators
 water system equivalent - water tank
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CONDUCTORS
carry electricity
 wires
 cables
 bus bars
 water equivalent - pipes
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LOADS
use electricity
 motors
 pumps
 fans
 hand tools
 lights
 heaters
 water equivalent -water wheel
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SWITCHES
control electricity
 floats
 push buttons
 disconnects
 duplex outlets / plugs
 water equivalent - valves
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Water system comparison
•Voltage = pressure
•Current = flow
•Resistance = system resistance to flow
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Ohms Law
voltage
resistance
amps
• Since voltage is constant,
current flow depends on resistance
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30 CFR 56/57. 12028
 56/57.12028 Testing grounding systems.
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Continuity and resistance of grounding
systems shall be tested immediately after
installation, repair, and modification; and
annually thereafter. A record of the resistance
measured during the most recent tests shall
be made available on a request by the
Secretary or his duly authorized
representative.
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Equipment grounding systems
 high resistance = low current
 low resistance = high current
 current flow is what trips fuses/breakers
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Be sure:
 all grounds ohms values are as low as
possible
 all wiring connections are clean & tight
 all conduit connections are clean & tight
 all plugs have ground prong in place
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Methods of Contact
 Step potential
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Difference in voltages (potential for current
flow) between person’s feet
 Touch potential
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Difference in voltages between points of
contact (usually hands and/or feet)
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HOW DO WE PROTECT
OURSELVES????
LOCK OUTTAG OUT!!
LOCKOUT/TAGOUT
Types of Devices
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LOCKOUT/TAGOUT
Types of Energy
Mechanical
Hydraulic
Pneumatic
Chemical
Thermal
Other
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LOCKOUT/TAGOUT
Preparation for Shutdown
Know the types and amounts of energy
that power it.
Know the hazards of that energy.
Know how the energy can be controlled.
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VERIFY-VERIFY-VERIFY!!!!
(ONLY IF YOU ARE QUALIFIED)
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HOW ELSE CAN WE
PROTECT
OURSELVES???
BY USING GFCI’S
How does the GFCI work
GFCIs constantly monitor electricity
flowing in a circuit.
If the electricity flowing into the circuit
differs by even a slight amount from
that returning, the GFCI will quickly
shut off the current flowing through that
circuit.
The advantage of using GFCIs is that
they can detect even small variations in
the amount of leakage current, even
amounts too small to activate a fuse or
circuit breaker.
GFCIs work quickly, so they can help
protect consumers from severe electric
shocks and electrocution.
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Some things a GFCI does not protect you from.
A GFCI does not protect a person who comes in contact with two
hot wires or any hot wire and the neutral wire.
A GFCI does not protect a person from feeling and reacting to shock
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ALWAYS REMBER!
Never work on a Energized Circuit. Unless you are trained to.
Always Lock and Tag
Never depend on another person to take the power off a circuit that you are going to
work on. Its your Life! This should even apply to home.
Just remember that Half of what you have is hers.
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Qualified Employees
 “One knowledgeable in the construction and
operation of the electric power generation,
transmission, and distribution equipment
involved, along with the associated hazards.”
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Qualified employees must have training to be
considered qualified.
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Qualified Employees
 Qualification extends to individual tasks
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Employees can be qualified in one task, but
not in another.
Examples:
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Racking breakers in & out
Changing fuses
Substation switching
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Unqualified Employees
 Unqualified employees and mobile
mechanical equipment must maintain a safe
distance from energized circuits
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Overhead power lines
Unguarded, exposed, energized conductors
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10 feet up to 50,000 volts
Additional 4 inches for every 10,000 volts over 50
kV
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Methods of Protection
 Insulation
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Verify insulation is intact
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Pay particular attention to flexible cords, such as
extension cords and tool power cords
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Methods of Protection
 Guarding
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Live parts operating at 50 volts or more must
be guarded
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Locate in a room or vault accessible only by
qualified persons
Permanent partitions or walls
 Metal-clad switchgear required if over 600 volts
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Distance
 8 feet (or more) above the floor
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Warning Signs
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Methods of Protection
 Grounding
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Service ground
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Neutral conductor is grounded
Equipment ground
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Frame or casing of tool or equipment is wired
directly to ground.
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Methods of Protection
 Circuit Protection Devices
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Fuses and Circuit Breakers
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Designed for equipment protection
Open circuit on high current
GFCI
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Ground Fault Circuit Interrupter
Designed for personnel protection
Opens quickly (1/40 second) on any ground fault
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Methods of Protection
 Safe Work Practices
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De-energize
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Lockout/Tagout energy sources
Use electric tools that are in good repair
Do not perform work you are not qualified for
Use appropriate protective equipment
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FR clothing, non-conductive hard hats, rubber
mats, line hose, hot sticks, rubber gloves, safety
glasses, face shields, etc.
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Methods of Protection
 Overhead Lines
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Only qualified employees can work on or near
All others maintain 10-foot rule, or
Owner/operator must de-energize and ground
lines prior to work
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Safe Work Practices
 DO
 Inspect cords for
damage
 De-energize and
L.O.T.O.
 Keep cords off
walkways
 Wear PPE
 Perform work only if
qualified
 Use a GFCI
 DON’T
 Overload plugs
 Upsize fuses, or use
substitutes
 Lay cords in water
 Use defective
equipment
 Assume household
current is safe
 Use conductive
ladders
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IF SOMEONE CONTACTS AN
ENERGIZED CONDUCTOR ---WHAT SHOULD ONE DO ??
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BLOOD TESTS TO WARN OF
FIBRILLATION TO OCCUR
 TROPONIN
 CPK ISOENZYME
 (CREATINE KINASE)
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PLEASE
REMEMBER---
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SAFETY FIRST!!!!
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THANK YOU ALL FOR
LISTENING!!!
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