Electrical Safety - Safety Training for the Non-Qualified

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University of Oklahoma

Summary Statement

Presentation provides an introduction to electricity, including definitions, basic concepts and how to avoid electrocutions.

Language of Electricity

  • Electricity: Negatively Charged Particles Moving Over A Conductor
  • Current: Movement Of Electrons Along A Conductor
  • Ground Or Grounding: The Draining Or Passage Of Electricity Into The Earth
  • Alternating Current: Current That Alternates Direction Through a Conductor
  • Direct Current: Current That Flows In The Same Direction Through A Conductor
  • Static Electricity: Electrical Charge Resulting From Friction Between Two Objects Or From Objects Striking
  • Shock: Condition When The Body Becomes A Part Of A Circuit
  • Polarity: The Flow Of Electrons In The Proper Direction(From the Source To The Device Or Negative To The Positive Through A Device)

How Does Electricity Work?

  • Like Charges Attract; Unlike Charges Repel
  • Electricity: Negatively Charged Particles (Electrons) Moving Over A Conductor
  • Conductor: A Material With A Relatively Low Resistance To The Flow Of Electrons
  • Insulator: Material That Has A High Resistance To The Flow Of Electrons

How Is The Seriousness Of An Electrical Shock Determined?

  • The Voltage (Pressure) On Circuit
  • Skin Resistance And Internal Resistance
  • Amount Of Current Flowing Through The Body, A Function Of Volts And Amps
  • Path The Current Takes
  • Body’s Reaction To The Shock
  • Length Of Time Electricity Is Applied

What Causes Shocks?

  • Touching Both Wires Of An Electrical Circuit
  • Touching One Energized Wire And A Ground Conductor
  • Touching The Case Of A Faulted Or “Short” Circuited Appliance Or Machine

Effects Of Electrical Shock

  • Volts Divided By Resistance in Ohms = Current In Amps
  • 120 Volts Divided By 100,000 Ohms = 0.0012 Amps Or 1.2 Milliamps
  • 1.2 Milliamps Is Perception Threshold
  • 10-20 Milliamps Is Painful; Let-Go Threshold; Can Kill In Time
  • 100 Milliamps Can Kill In A Second; Can’t Let Go
  • 200 Milliamps Kills; Causes Heart Fibrillation; Burns Human Flesh

Measuring Electricity

  • Volts: A Measurement Of Electrical Pressure
  • Watts: A Unit Of Electrical Power
  • Amperes: A Measurement Of The Volume Of Electrical Current
  • Ohms: Measure Of The Resistance To The Flow Of Electrons

Electrical Safety Devices

  • Insulation
  • Ground Fault Circuit Interrupters (GFCIs)
  • Double-Insulated Devices
  • Grounding (Circuit And Equipment)
  • Guarding
  • Fuses And Circuit Breakers
  • Personal Protective Equipment

Safe Work Practices

  • Know Where The Hazards Are
  • Properly Maintain Equipment
  • No Exposed Parts Or Energized Surfaces
  • Use Barriers And Devices Where Appropriate
  • No Conductors To Walk On Or Trip On
  • No Jewelry, Or Other Metal Objects Around Electricity
  • Never Use Plugs Or Receptacles That Can Alter Polarity
  • Properly Plug All Connecting Plug-Ins
  • Install And Use Protective Devices
  • Stay Away From All Unguarded Conductors
  • Never Overload A Circuit Or A Conductor

Working Safe With Cords

  • Inspect Cords Before Each Use
  • Be Sure Plug And Receptacle Have Proper Mating Configuration
  • To Unplug, Never Pull On The Cord, Pull On The Plug
  • Don’t Use Nails, Staples, Screws, Etc., To Attach Or Fasten A Cord Or Plug
  • Two Conductor Cords Are Illegal
  • Damaged Cords Should Never Be Used
  • Ensure Enough Slack To Prevent Strain On Plug Or Receptacle
  • A Plug-Receptacle Should Have At Least 8 Ounces Of Contact Tension
  • Cords Should Be Kept Clean And Free Of Kinks And Insulation Breaks
  • Cords Crossing Vehicular Or Personnel Passageways Should Be Protected, Sign Posted, And Used Temporarily Or In An Emergency
  • Cords Should Be Of Continuous Length And Without Splices

If Electrocution Occurs

  • DO NOT Touch The Victim Or The Conductor
  • Shut Off The Current At The Control Box
  • If Shutoff Not Immediately Available, Use Non-Conducting Material To Free Victim
  • Call For Help
  • If Necessary And You Know How, Begin CPR
  • In Dealing With Electricity, Never Exceed Your Expertise

Control Of Circuits

  • Only Switches And Breakers Designed To Do So May Be Used To Control Current
  • Only Approved Equipment May Be Used In Wet Or Damp areas. Always Use GFCI
  • Never Energize Equipment When Shields Or Guards have Been Removed
  • Always Honor LockOut/TagOut Situations

Best Advice

Treat Electricity With The Respect It Demands, And It Will Serve You Efficiently And Effectively