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EFCOG Electrical Improvement Project
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Electrical Hazards Awareness Electrical Hazards Awareness BriefingBriefing
Basic Electrical Safety Hazard Awareness for Non-Electrical Personnel
Module 1
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PurposePurpose• The purpose – worker safety
Raising your awareness of electrical hazards Instructing you on how to recognize electrical hazards Providing ways to eliminate, remove and prevent
electrical hazards in the workplace Emphasizing the extreme importance of observing all
electrical safety requirements and practices Instructing you on what to do during an electrical
accident
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IntroductionIntroduction
• An average of one worker is electrocuted on the job every day
• An average of one person is electrocuted in the home every 36 hours
• Electrical incidents are far more likely to be fatal than other types
• There are four main types of electrical injuries:Electrocution (death due to electrical shock)Electrical shockBurnsFalls
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Electrical TerminologyElectrical Terminology
• Current – the movement of electrical charge• Resistance – opposition to current flow• Voltage – a measure of electrical force• Conductors – substances, such as metals, that
have little resistance to electricity• Insulators – substances, such as wood, rubber,
glass, and bakelite, that have high resistance to electricity
• Grounding – a conductive connection to the earth which acts as a protective measure
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Electrical ShockElectrical Shock
• Received when current passes through the body
• Severity of the shock depends on:Path of current through the bodyAmount of current flowing
through the bodyLength of time the body is in the
circuit
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Dangers of Electrical ShockDangers of Electrical Shock
• Currents greater than 75 mA* can cause ventricular fibrillation (rapid, ineffective heartbeat)
• Will cause death in a few minutes unless a defibrillator is used
• 75 mA is not much current – a small power drill uses 30 times as much
* mA = milliampere = 1/1,000 of an ampere
Defibrillator in use
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How is an electrical shock received?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
110 volts relative to groundThe white wires are at zero volts because they
are connected to ground• If you come into contact with an energized (live)
black wire, and you are also in contact with the white grounded wire, current will pass through your body and YOU WILL RECEIVE A SHOCK
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How is an electrical shock received?How is an electrical shock received?(cont’d)(cont’d)
• If you are in contact with an energized wire or any energized electrical component, and also with any grounded object, YOU WILL RECEIVE A SHOCK
• You can even receive a shock when you are not in contact with a groundIf you contact both wires of a 240-volt cable,
YOU WILL RECEIVE A SHOCK and possibly be electrocuted
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Low Voltage Does Not Mean Low Low Voltage Does Not Mean Low HazardHazard
• A small amount of electrical current can cause injury, even death The current from a 7.5-watt, 120-volt lamp, passing
across the chest, is enough to cause fatal electrocution
• Deaths from 120 volts represent about 12 percent of all electrocutions
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Electrical Burns Electrical Burns
• Most common shock-related, nonfatal injury
• Occurs when you touch electrical wiring or equipment that is improperly used or maintained
• Typically occurs on the hands
• Very serious injury that needs immediate attention
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Recognize the HazardsRecognize the HazardsHave you seen areas like these?
Both are NEC violations and present a safety hazard, based on inaccessible circuit control devices
Do not block the working space around electrical equipment (600 volts, nominal, or less). This space provides and maintains sufficient access and working space to permit ready and safe operation and maintenance of such equipment
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Recognize the HazardsRecognize the HazardsWhat do you do if you see these situations?
Call a timeout and inform your supervisor
Do not remove or open receptacle covers, switch plates, or covers of electrical equipment unless qualified and authorized
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Recognize the HazardRecognize the Hazard
• Assume all exposed wiring is energized until proven otherwise. STOP, protect the area and contact supervision if you encounter this situation
Potentially energized
exposed wire with status
unknown
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Recognize the HazardRecognize the HazardTripping and Abrasion HazardsTripping and Abrasion Hazards
• Don’t cause tripping hazards or create pinch points for cords
• If you must run a cord temporarily across the floor, protect your co-workers by covering the cord appropriately
Not OK OK
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Recognize the HazardsRecognize the HazardsRemove from service damaged or frayed cordsReport electrical equipment damage to your supervisor
Stay clear of bare, exposed wiring and REPORT IT!
• Visually inspect electrical equipment before each use for damage and/or external defects such as loose, missing or deformed parts, pinched or crushed outer jackets or insulation. This type of external damage may indicate internal damage to the equipment.
• Electrical cords that are worn or damaged must be replaced without delay.
• Before cleaning electrical equipment, turn it off and unplug it.
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Recognize the Hazard Recognize the Hazard Cabinets, Boxes, and FittingsCabinets, Boxes, and Fittings
• Junction boxes, pull boxes and fittings must have approved covers in place
• Unused openings in cabinets, boxes and fittings must be closed (no missing knockouts)
• Photo shows violations of these two requirements
• Report this situation to management
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Recognize the HazardsRecognize the Hazards
Never daisy chain multi-outlet strips (plugging into each other)
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Recognize the HazardRecognize the Hazard
• Observe all barricades, postings, and warning signs regarding dangerous voltages
• Do not enter or approach electrical work areas unless specifically authorized and qualified.
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Recognize the HazardsRecognize the Hazards
Not permitted and should be taken out of service!
Electrical boxes with knockouts are designed to be installed in or on walls, not used as multi-outlet extension cords.
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Recognize the HazardRecognize the HazardGrounding PathGrounding 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
• Do not make alterations to polarized blades or ground pin to make plug fit into non-polarized or non-grounded outlet
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Recognize the HazardsRecognize the Hazards• Electrical hazards may exist
overhead indoors Crane power rails are an
example
• Electrical hazards may also exist overhead outdoors Most lines are bare and
higher voltage than the “normal” insulated wiring
Contact is not required to initiate an arc or cause shock and burn injuries
Maintain safe approach distances when working near energized overhead lines
Stay at least 10 feet away from overhead lines
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Recognize the HazardRecognize the Hazard
• Electrical equipment and wiring must not be exposed to physical damage
• Picture shown here is physical damage to conduit
• Stay away from damaged equipment and report equipment damage to supervision
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Recognize the HazardRecognize the Hazard
• Treat it as it is designed to be treated
• Pull the plug, not the cord
Handle portable electrical equipment carefully, in accordance with manufacturers instructions, and in a manner that will not cause damage
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Clues that Electrical Hazards May Exist
• Tripped circuit breakers or blown fuses• Hot to the touch on tools, wires, cords, connections, or junction
boxes• Dim and flickering lights• Sizzles and buzzes-unusual sounds from electrical system• Odor of hot insulation• Mild tingle from contact with case or equipment• GFCI that shuts off a circuit• Worn or frayed insulation around wire or connection• Burn marks or discoloration on receptacle plates or plug prongs
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Ground-Fault Circuit InterrupterGround-Fault Circuit Interrupter
• Always use a GFCI receptacle or circuit for cord connected tools and equipment used outdoors or near water
• This device protects you from electrocution• The GFCI detects a difference in current between
the black and white circuit wires (This could happen when electrical equipment is not working correctly, causing current “leakage” – known as a ground fault.)
• Perform the test function on the GFCI to determine if it is functioning properly by pushing the button to verify it shuts off
• Repeated resetting not allowed. Contact local E&I to troubleshoot if GFCI continues to trip.
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Prohibited Uses of Flexible CordsProhibited Uses of Flexible CordsExamplesExamples
Substitute for fixed wiring
Run through walls, ceilings, floors, doors, or windows
Concealed behind or attached to building surfaces
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Safe PracticesSafe PracticesCord ControlCord Control
• Do not fasten electrical cords to surfaces with staples, nails, wire, or any other method that might damage the cord
• Extension cords Place them in appropriate locations Understand they are for temporary use only
• Tool cords Keep track of them, to assure they do not become
damaged• Do not plug or unplug electrical cords with wet hands or
while standing in water
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Safe PracticesSafe PracticesCord Control Cont.Cord Control Cont.
• Do not use portable electrical equipment or extension cords in wet or damp locations without a ground fault circuit interrupter (GFCI) ahead of the plug connection
• GFCIs are also required for temporary power applications in wet or damp locations, including extension cords
• Remove loads from an appliance or extension cord before unplugging it
• If a plug won’t stay placed snugly or fits loosely in a receptacle, don’t use it; call local E&I to replace it
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Safe PracticesSafe PracticesResetting BreakersResetting Breakers
• When circuit breakers and fuses trip, don’t reset or replace them!
• Only qualified and authorized personnel are allowed to reset breakers and replace fuses
• Contact qualified personnel to determine the cause of trips
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Safe PracticesSafe PracticesConductive ApparelConductive Apparel
• Don’t wear loose conductive apparel, (such as rings, watch bands, bracelets, necklaces, etc.) when plugging in electrical cords
Burn from arc
Charm contacted plug
Charm contacted plug here
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Safe PracticesSafe PracticesWall PenetrationsWall Penetrations
• When penetrating walls to hang pictures, bulletin boards, signs, understand and follow site requirements to ensure that concealed electrical wiring, conduit or piping will not be contacted
• A non-obtrusive survey (e.g., Ground Penetrating Radar, proximity detection device) may be required, along with a review of applicable drawings, to ensure that the electrical system is not penetrated or contacted
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Safe PracticesSafe PracticesEquipment ApplicationsEquipment Applications
• Consumer electrical equipment or appliances should be tested and labeled by a recognized testing laboratory. (Look for the UL, CSA, ETL or MET Label)
• Always read and follow the manufacturers instructions carefully. Be sure that the equipment or tool is rated for the environment (wet, damp, etc.)
• Plug portable space heaters directly into outlet: Do not use extension cord. Use a circuit with as little else on it as possible since space heaters take a lot of power.
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Safe PracticesSafe PracticesQualificationsQualifications
• Do not remove/replace receptacle covers, switch plates, or covers of electrical equipment that may contain energized conductors without electrical qualifications and authorization
• Only qualified electrical workers may perform activities such as electrical probing, measuring and testing electrical energized components (such as performing an “absence of voltage” test)
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Electrical EmergenciesElectrical Emergencies
• Do you know what dangers could be encountered? Attempts to rescue an accident victim may pose as
great a hazard for the rescuer as it does for the victim
A victim of an electrical accident is often unable to move or release the electrical conductor, because of muscle clamping
Caution should be a primary consideration during any electrical accident or emergency
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Electrical EmergenciesElectrical Emergencies
• Do you know the proper actions to take if you see someone receiving a shock or locked onto an energized electrical line?
• Approaching the accident: Never rush into an accident situation-Assess your own safety Call 911 as soon as possible Unplug portable electrical equipment to remove power (1st choice) Open a disconnecting device or circuit breaker to de-energize fixed
electrical equipment Use a dry wood broom, leather belt, plastic rope, or something
similar that is non-conductive such as wood or plastic cane with hook on the end to free the person from the energy source
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Electrical EmergenciesElectrical EmergenciesDowned Power LinesDowned Power Lines
• Do you know the proper actions to take? • Approaching the accident:
Move away from downed power line Shuffle away with small steps keeping feet together If you see someone in direct contact with line, do not
touch person Call 911 as soon as possible Do not attempt to move downed power line Get the aid of trained electrical personnel if possible If you are in your car and it is it contact with the downed
line, stay in car. Honk horn for help and tell others to stay away from your vehicle
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What Now?What Now?
• Inspect your work areas Existing unsafe conditions
- Bare wires
- Open enclosures containing exposed wires
- Loose or missing covers or fasteners
- Use good electrical safe practices- No daisy-chaining
- No overloading outlets
- Pull on plug, not cord
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What Now?What Now?
• What do I do if I identify a hazardous condition? When unsafe electrical conditions are found, correct
them if possible, or take steps to warn other employees
Report unsafe electrical conditions verbally and/or in writing to supervision so corrective actions can be taken immediately
Barricade the area, if an immediate hazard exists Notify supervision for correction and documentation
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For More InformationFor More Information
• Contact: Your Site Electrical Safety Officer, or Your Safety Engineer
• WEB Sites See DOE Electrical Safety Campaign at
www.eh.doe.gov/paa/electrical See Electrical Safety Foundation International at
www.electrical-safety.org
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