Electrical Safety Unqualified Worker
Session Objectives • You will be able to: • Understand the hazards of electricity • Identify and avoid common electrical hazards • Follow safe work practices around electrical equipment
How Does Electricity Work? • Flow of electrons, similar to flow of water through a pipe • Voltage = “Pressure” • Amperage = “Flow” • Resistance = “Restriction”
Electrical Hazards • Contact with overhead and buried power lines • Contact with damaged electrical equipment • Improper wiring • Overloading • Unsafe work practices
Electrical Injuries • Cardiac arrest and respiratory failure from electrical shock or electrocution • Muscle, nerve, and tissue destruction from current passing through the body • Burns from arc flash and arc blast • Thermal burns from contact with source • Secondary injuries
How Electrical Shock Occurs • “Shock”—electrical energy contacts your body • Contact two wires or components at different voltages • Contact an energized wire or component and a grounded object
Severity of Electrical Shock Severity depends on: • Amount of electrical current—higher is more dangerous • Duration—longer is more dangerous • Path through the body—through the heart is most dangerous
Injuries from Electrical Shock • Electrocution • Injuries: • Blood vessels, nerves, organs, and burns • Secondary injuries • Falls • Trauma
Arc Flash and Arc Blast • Arc Flash—electricity flows through the air • Temperatures as high as 35,000 degrees, vaporizing metal • Severe skin burns • Arc Blast—pressure wave from an arc flash • Severe injuries from blast • Facility and equipment damage Image Credit: OSHA
Electrical Burns • Burns are a common shock-related injury • Electricity generates heat in the body • 2nd and 3rd degree • Some severe burns appear minor on the outside • Thermal burns from hot surfaces and fires
Electrical Hazards—Any Questions? • Do you understand the hazards and injuries of electricity in the workplace?
Emergency Response and First Aid for Shock • If a person is shocked: • Do not touch the person during the shock event • Shut off electrical current • Call for help • Administer first aid and CPR; use AED
Stay Away from Power Lines • Overhead power lines • Stay at least 10 feet away • Keep equipment at least 10 feet away • Add 4 inches for every 10 kV over 50 kV • Buried power lines • Don’t dig until verified that buried lines and other utilities are not in the area
Report and Don’t Use Damaged Equipment • Stop using and report: • Broken or missing covers • Damaged tools • Damaged cords • Damaged equipment
Ensure Electrical Equipment Is Grounded • If no safe path to ground, exposed parts can become energized • Electric power-operated tools and equipment must be grounded or double-insulated • Path to ground must be continuous
Ground Fault Circuit Interrupter (GFCI) • GFCIs detect current between the two circuit wires • Trip at about 5 mAmp • Can get a shock before it trips • If it keeps tripping there is a problem • Need to be periodically tested
Follow Lockout/Tagout Procedures • Devices that prevent access to hazardous energy • Lockout ensures equipment isn’t accidentally restarted • Tagout used where lockout not feasible • Follow lockout/tagout program procedures
Follow Safe Work Practices • Only qualified persons may work on or near exposed electrical equipment and wiring • Don’t wear conductive apparel • Work area must be illuminated • Don’t allow conductive liquids near electrical work or equipment • Do not defeat electrical interlocks • Use nonconductive ladders
Use Portable Electrical Equipment Safely • Inspect for damage • Check cord and ground • Use safely • Don’t lift by cord • Dry hands when plugging and unplugging • GFCI in wet locations
Circuit Protective Devices • Circuit breakers and fuses are designed to trip if overloaded • Don’t reset unless authorized to do so • Contact a qualified person to investigate
Stay Away from Electrical Work Areas • Electrical work areas need to be isolated • Alerting Techniques • Safety Signs and Tags • Barricades • Attendants
Follow the Electrical Safety Program • Written procedure includes: • Responsibilities • Procedures • Safe work practices • Personal protective equipment • Only qualified personnel may work on or near exposed energized equipment!
Safety Practices—Any Questions? • Do you understand: • First aid? • Electrical equipment? • Electrical circuits? • Lockout/tagout? • Safe work practices? • The electrical safety program?
Key Things to Remember • Exposure to electricity can cause electrocution, shock, electric and thermal burns, arc flash and arc blast burns, and secondary injuries • Watch carefully for electrical hazards • Follow safe work practices, including emergency response procedures • Follow the electrical safety program • Seek assistance from a qualified person