Electrical Hazards Awareness Briefing

1
Electrical Hazards Awareness Briefing

• Basic Electrical Safety Hazard Awareness for
• Non-Electrical Personnel
• Module 1

2
Purpose

• 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

3
Introduction

• 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 shock
• Burns
• Falls

4
Electrical 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

5
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

6
Dangers 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

Defibrillator in use
mA milliampere 1/1,000 of an ampere
7
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 ground
• The 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

8
How is an electrical shock received?(contd)

• 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 ground
• If you contact both wires of a 240-volt cable,
  YOU WILL RECEIVE A SHOCK and possibly be
  electrocuted

9
Low Voltage Does Not Mean Low Hazard

• 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

10
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

11
Recognize the Hazards
Have 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
12
Recognize the Hazards
What 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
13
Recognize 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
14
Recognize the HazardTripping and Abrasion
Hazards
Not OK
OK

• Dont 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

15
Recognize the Hazards
Remove from service damaged or frayed
cords Report electrical equipment damage to your
supervisor

• 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.

Stay clear of bare, exposed wiring and REPORT IT!
16
Recognize the Hazard Cabinets, 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

17
Recognize the Hazards
Never daisy chain multi-outlet strips (plugging
into each other)
18
Recognize 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.

19
Recognize 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.
20
Recognize the HazardGrounding 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

21
Recognize 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
22
Recognize 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

23
Recognize 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
24
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

25
Ground-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
  EI to troubleshoot if GFCI continues to trip.

26
Prohibited Uses of Flexible CordsExamples
Substitute for fixed wiring
Run through walls, ceilings, floors, doors, or
windows
Concealed behind or attached to building surfaces
27
Safe PracticesCord 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

28
Safe PracticesCord 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 wont stay placed snugly or fits
  loosely in a receptacle, dont use it call local
  EI to replace it

29
Safe PracticesResetting Breakers

• When circuit breakers and fuses trip, dont 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

30
Safe PracticesConductive Apparel

• Dont wear loose conductive apparel, (such as
  rings, watch bands, bracelets, necklaces, etc.)
  when plugging in electrical cords

Charm contacted plug
Burn from arc
Charm contacted plug here
31
Safe PracticesWall 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

32
Safe PracticesEquipment 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.

33
Safe PracticesQualifications

• 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)

34
Electrical 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

35
Electrical 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

36
Electrical EmergenciesDowned 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

37
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

38
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

39
For 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