Electrical Safety Unqualified Worker
Session Objectives Understand the hazards of electricity Identify and avoid common electrical hazards Follow safe work practices around electrical equipment
How Does Electricity Work? Voltage can be compared to pressure or force. The higher the voltage, the more likely it is to cause injury, just like the difference in force between high and low water pressure.
How Does Electricity Work? Amperage can be compared to flow. Higher amperage means a higher volume of electricity, in much the same way as a largediameter pipe will allow a greater flow of water than a smalldiameter pipe.
How Does Electricity Work? Finally, resistance can be compared to restrictions in a water pipe. When electricity has resistance, this generates heat, which can result in fires or damaged equipment.
Electrical Hazards Contact with power lines Contact with damaged electrical equipment Improper wiring Can short circuit Overloading Unsafe work practices
Electrical Injuries Cardiac arrest and respiratory failure Thermal burns Muscle, nerve, and tissue destruction Burns Secondary injuries
How Electrical Shock Occurs Contact with: Electrical energy Two current-conducting wires at different voltages An energized wire and a grounded object
Severity of Electrical Shock Amount of electrical current higher is more dangerous Duration longer is more dangerous Path through the body through the heart is most dangerous
Effects of Electrical Current on the Body This slide shows the effects of different flows of electrical currents or amperage on the body when the current flows for one second. Note that the designation mamp means milli-amp, or one one-thousandth of an amp. You ll see that a small fraction of one amp of electricity is enough to cause a painful shock, respiratory arrest, and even death. At more than one amp, cardiac arrest and death is likely.
Effects of Electrical Current on the Body 0.5-3 mamp Faint, tingling sensation 6-30 mamp Painful shock, severe muscle contractions, no muscle control 50-150 mamp Extremely painful shock, respiratory arrest, severe muscle contractions, death may occur 1-4 Amp Ventricular fibrillation, nerve damage, death is likely 10 Amp Cardiac arrest, severe burns, death is probable
Injuries from Electrical Shock Electrocution Powerful enough to cause death Injuries Nerves and body organs Secondary injuries Falls, striking, etc.
Arc Flash and Arc Blast Arc Flash electricity flows through the air Can travel so stay out of the path of a potential arc flash Can be caused by: Circuit disconnectors open and close Tools Equipment fails Image Credit: OSHA Arc Blast pressure wave from an arc flash
Electrical Burns Burns are a common shock-related injury Electricity generates heat in the body 2nd & 3 rd degree burns Damage to skin and organs Thermal burns through contact with hot surfaces Clothes or equipment can catch on fire
How to Avoid Electrical Hazards
Stay Away from 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 Don t dig near buried lines
Report and Don t Use Damaged Equipment Broken or missing covers Damaged tools Damaged cords Damaged equipment
Ensure Electrical Equipment Is Grounded Exposed parts can become energized Always ground electric tools and equipment Path to ground must be continuous
Circuit Protective Devices Circuit breakers trip if overloaded Don t reset unless authorized Contact a qualified person to investigate
Ground Fault Circuit Interrupter (GFCI) 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 tested periodically
Follow Lockout/Tagout Procedures Devices that prevent access to hazardous energy Lockout ensures equipment isn t accidentally restarted Tagout is used where lockout is not feasible
Follow Lockout/Tagout Procedures Employees of Mangan Inc. and Mangan Biopharm do not initiate Lockout / Tagout If group locks are necessary to complete the work, the Mangan employee must be trained by Mangan as follows: OSHA Lockout / Tagout training Hands on training Contact your safety representative before engaging in any Lockout / Tagout activities.
Follow Safe Work Practices Work on electrical equipment only if qualified Wear safety equipment Illuminate work area Use nonconductive ladders
Follow Safe Work Practices (cont.) Don t wear conductive apparel Don t use conductive liquids Do not defeat electrical interlocks
Use Portable Electrical Equipment Safely Inspect for damage Check cord and ground Don t lift by cord Dry hands when plugging and unplugging GFCI in wet locations
Stay Away from Electrical Work Areas Electrical work areas need to be isolated Alerting techniques Safety Signs and Tags Barricades Attendants
Stay Away from Electrical Work Areas Only employees designated as Qualified are authorized to work Within the Prohibited Approach Boundary. As an Un-qualified worker, stay outside of the Flash Protection Boundary.
Follow the Electrical Safety Program Written procedure includes: Job Safety Analysis Assigning responsibilities Ensuring safe work practices Personal protective equipment Only qualified personnel may work on or near exposed energized equipment! Within the prohibited approach boundary
Safety Practices Any Questions? Contact safetytraining@manganinc.com
Key Things to Remember Exposure to electricity can be dangerous Watch for electrical hazards Follow safe work practices Follow the electrical safety program Seek assistance from a qualified person