1. Electrical Safety INSTRUCTOR’S NOTES:
This presentation is designed to assist trainers conducting OSHA 10-hour General Industry outreach training for youth workers. Since youth workers are the target audience, this presentation may cover hazard identification, avoidance, and control – not standards. No attempt has been made to treat the topic exhaustively. It is essential that trainers tailor their presentations to the needs and understanding of their audience.
This presentation is not a substitute for any of the provisions of the Occupational Safety and Health Act of 1970 or for any standards issued by the U.S. Department of Labor. Mention of trade names, commercial products, or organizations does not imply endorsement by the U.S. Department of Labor.

2. Electrical Safety
Electricity is an important part of our modern world and sometimes it is easy to forget just how dangerous it can be.
Given the correct circumstances, electricity can cause serious injuries or even death. 
INSTRUCTOR’S NOTES:

3. Electrical Safety
Electrocution is the cause of 12% of all workplace deaths among young workers.
Electrocution is the third leading cause of work-related deaths among 16 and 17-year-olds.
INSTRUCTOR’S NOTES:

4. Electrical Injuries The most common types of electrical injuries are:
Electrical shock
Electrocution (death due to electrical shock)
Burns
Falls
INSTRUCTOR’S NOTES:
There are four main types of electrical injuries are electrical shock, electrocution (death due to electrical shock), falls and burns.
Shock occurs when the body becomes part of the path through which electrons flow. The resulting effect on the body can be either direct or indirect. With a direct shock, injury or death occurs. Currents less than 30 milliamps can cause death. The indirect effect of an electrical shock might be from a fall from a ladder or other elevated work surface, or from being knocked or pulled into operating machinery.
Burns can result from touching electrical wiring or equipment that is improperly used or maintained (usually burn injuries occur to the hands). However, burns can also result from electrical explosions or fires. An electrical explosion occurs when electricity provides a source of ignition for an explosive mixture in the atmosphere, usually caused by overheated conductors or equipment or sparking at switch contacts. An electrical fire is often caused by defective or misused electrical equipment, improperly spliced wiring and overheated circuits.

5. Electrical Shock
Touching a live wire and an electrical ground will cause a shock.
INSTRUCTOR’S NOTES:
You will receive an electrical shock if a part of your body completes an electrical circuit by touching a live wire and an electrical ground.
A severe shock can cause much more damage to the body than is visible. A person may suffer internal bleeding and destruction of tissues, nerves, and muscles. Sometimes the hidden injuries caused by electrical shock result in a delayed death. Shock is often only the beginning of a chain of events. Even if the electrical current is too small to cause injury, your reaction to the shock may cause you to fall, resulting in bruises, broken bones, or even death.
If an electrocution occurs:
DO NOT touch the victim or the conductor
Shut off the current at the control box
If shutoff is not immediately available, use non-conducting material to free the victim
Call for help
If necessary and you know how, begin CPR
In dealing with electricity, never exceed your expertise

6. Electrical Shock
Touching two live wires of different voltages will cause electrical shock.
INSTRUCTOR’S NOTES:
Your body can connect the wires if you touch both of them at the same time. Current will pass through your body and you will be shocked.
You can even receive a shock when you are not in contact with an electrical ground. If you come into contact with both live wires of a 240-volt cable, you will be shocked. You can also receive a shock from electrical components that are not grounded properly. Even contact with another person who is receiving an electrical shock may cause you to be shocked.

7. LOW VOLTAGE DOES NOT MEAN LOW HAZARD
Electrical Shock
The severity of the shock depends on:
Path of the current through your body
Amount of current flowing through your body
Length of time your body is in contact with the circuit
INSTRUCTOR’S NOTES:
The severity of injury from electrical shock depends on the amount of electrical current and the length of time the current passes through the body. For example, 1/10 of an ampere (amp) of electricity going through the body for just 2 seconds is enough to cause death. The amount of internal current a person can withstand and still be able to control the muscles of the arm and hand can be less than 10 milliamperes (milliamps or mA). Currents above 10 mA (1/100 of an amp) can paralyze or "freeze" muscles. When this "freezing" happens, a person is no longer able to release a tool, wire, or other object. In fact, the electrified object may be held even more tightly because the muscles are frozen, resulting in longer exposure to the shocking current. For this reason, hand-held tools that give a shock can be very dangerous. If you can't let go of the tool, current continues through your body for a longer time, which can lead to respiratory paralysis (the muscles that control breathing cannot move). You stop breathing for a period of time. People have stopped breathing when shocked with currents from voltages as low as 49 volts. Usually, it takes about 30 mA of current to cause respiratory paralysis.
A small current that passes through the trunk of the body (heart and lungs) is capable of causing severe injury or electrocution. Low voltages can be extremely dangerous because, all other factors being equal, the degree of injury increases the longer the body is in contact with the circuit. LOW VOLTAGE DOES NOT MEAN LOW HAZARD
LOW VOLTAGE DOES NOT MEAN LOW HAZARD

8. Burns
Burns are the most common injury caused by electricity. The three types of burns are:
Electrical burns
Arc burns
Thermal contact burns
Electrical burns can occur when you come into direct contact with electricity.
INSTRUCTOR’S NOTES:
The most common shock-related, nonfatal injury is a burn. Burns caused by electricity may be of three types: electrical burns, arc burns, and thermal contact burns.
Electrical burns can result when a person touches electrical wiring or equipment that is used or maintained improperly. Typically, such burns occur on the hands. Electrical burns are one of the most serious injuries you can receive. They need to be given immediate attention.

9. Burns
An arc occurs when there is a gap between conductors and current travels through the air.
Electrical burns
Arc burns
Thermal contact burns
INSTRUCTOR’S NOTES:
Arc-blasts occur when powerful, high-amperage currents arc through the air. Arcing is the luminous electrical discharge that occurs when high voltages exist across a gap between conductors and current travels through the air. This situation is often caused by equipment failure due to abuse or fatigue. Temperatures as high as 35,000°F have been reached in arc-blasts.

10. Burns
Thermal contact burns can occur when electricity ignites combustible material.
Electrical burns
Arc burns
Thermal contact burns
INSTRUCTOR’S NOTES:
Thermal burns may result if an explosion occurs when electricity ignites an explosive mixture of material in the air. This ignition can result from the buildup of combustible vapors, gasses, or dusts. Ignition can also be caused by overheated conductors or equipment that ignite flammable material or by normal arcing at switch contacts or in circuit breakers. Clothing may catch fire and a thermal burn may result from the heat of the fire.

11. Falls Another common type of electrical injury is falling.
Workers who experience a shock on elevated work surfaces such as platforms, ladders or scaffolds can fall resulting in serious injury or death.

12. Electrical Hazards
To avoid injuries, you should be aware of electrical hazards. Some of the most common electrical hazards are:
Exposed electrical parts
Overloaded circuits
Defective insulation
Improper grounding
Damaged power tools
Overhead power lines
Wet conditions
INSTRUCTOR’S NOTES:
The first step toward protecting yourself is recognizing the many hazards you face on the job. To do this, you must know which situations can place you in danger. Knowing where to look helps you to recognize hazards.
Let’s take a closer look at each of these hazards.

13. Exposed Electrical Parts
Exposed electrical parts can include:
Breaker boxes without a cover
Electrical terminals in motors, appliances, and electronic equipment
INSTRUCTOR’S NOTES:
Electrical hazards exist when wires or other electrical parts are exposed. Wires and parts can be exposed if a cover is removed from a wiring or breaker box. The overhead wires coming into a home may be exposed. Electrical terminals in motors, appliances, and electronic equipment may be exposed. Older equipment may have exposed electrical parts. If you contact exposed live electrical parts in any way, you will be shocked. You need to recognize that an exposed electrical component is a hazard.
(g) 600 Volts, nominal, or less.
(2) Guarding of live parts.
(i) Except as required or permitted elsewhere in this subpart, live parts of electric equipment operating at 50 volts or more shall be guarded against accidental contact by approved cabinets or other forms of approved enclosures, or by any of the following means:
[A] By location in a room, vault, or similar enclosure that is accessible only to qualified persons.
[B] By suitable permanent, substantial partitions or screens so arranged that only qualified persons will have access to the space within reach of the live parts. Any openings in such partitions or screens shall be so sized and located that persons are not likely to come into accidental contact with the live parts or to bring conducting objects into contact with them.
[C] By location on a suitable balcony, gallery, or platform so elevated and arranged as to exclude unqualified persons.
[D] By elevation of 8 feet or more above the floor or other working surface.
(ii) In locations where electric equipment would be exposed to physical damage, enclosures or guards shall be so arranged and of such strength as to prevent such damage.
(iii) Entrances to rooms and other guarded locations containing exposed live parts shall be marked with conspicuous warning signs forbidding unqualified persons to enter.
(g)(2)(iii)

14. Overloaded Circuits
Overloading a circuit increases the potential for fires to occur. Overload hazards exist if:
Too many devices are plugged into a circuit
The wire insulation melts
An improper overcurrent protection device is used
No overcurrent protection device is used
INSTRUCTOR’S NOTES:
Overloads in an electrical system are hazardous because they can produce heat or arcing. Wires and other components in an electrical system or circuit have a maximum amount of current they can carry safely. If too many devices are plugged into a circuit, the electrical current will heat the wires to a very high temperature which may cause a fire. If any one tool uses too much current, the wires will heat up.
If the wire insulation melts, arcing may occur and cause a fire in the area where the overload exists, even inside a wall. If the circuit breakers or fuses are too big (high current rating) for the wires they are supposed to protect, an overload in the circuit will not be detected and the current will not be shut off. A circuit with improper overcurrent protection devices – or one with no overcurrent protection devices at all – is a hazard.

15. Overloaded Circuits Overcurrent protection devices include:
Circuit breakers
Fuses
Ground fault circuit interrupters (GFCI)
A circuit breaker automatically “trips” and shuts off the current in a circuit if it becomes overloaded.
INSTRUCTOR’S NOTES:
In order to prevent too much current in a circuit, a circuit breaker or fuse is placed in the circuit. If there is too much current in the circuit, the breaker "trips" and opens like a switch. If an overloaded circuit is equipped with a fuse, an internal part of the fuse melts, opening the circuit. Both breakers and fuses do the same thing: open the circuit to shut off the electrical current.
Circuit breaker - an overcurrent protection device that automatically shuts off the current in a circuit if an overload occurs.

16. Overloaded Circuits
A fuse contains an internal part that melts and shuts off the current if there is an overload.
Circuit breakers
Fuses
Ground fault circuit interrupters
INSTRUCTOR’S NOTES:
Fuse - an overcurrent protection device that has an internal part that melts and shuts off the current in a circuit if there is an overload.

17. Overloaded Circuits
A ground fault circuit interrupter (GFCI) detects current leaking from a circuit to ground and shuts the current off.
Circuit breakers
Fuses
Ground fault circuit interrupters
Receptacle type
INSTRUCTOR’S NOTES:
GFCI - ground fault circuit interrupter - a device that detects current leakage from a circuit to ground and shuts the current off.
GFCI's help protect you from electrical shock by continuously monitoring the circuit. However, a GFCI does not protect a person from line-to-line hazards such as touching two "hot" wires (240 volts) at the same time or touching a "hot" and neutral wire at the same time. Also be aware that instantaneous currents can be high when a GFCI is tripped. A shock may still be felt. Your reaction to the shock could cause injury, perhaps from falling.
Test GFCI's regularly by pressing the "test" button. If the circuit does not turn off, the GFCI is faulty and must be replaced.
GFCI’s compare the amount of current going into electric equipment with the amount of current returning along the circuit. If the difference exceeds 5 milliamperes (the amount of current that delivers a slight shock), the GFCI automatically shuts off the power in as little as 1/40 of a second.

18. Defective Insulation
To protect you, electrical wires are insulated by a plastic or rubber covering. Insulation prevents conductors from coming in contact with each other and with people.
Make sure the insulation of tools and cords you are using is not damaged.
INSTRUCTOR’S NOTES:
Insulation that is defective or inadequate is an electrical hazard. Usually, a plastic or rubber covering insulates wires. Insulation prevents conductors from coming in contact with each other or with people.
Extension cords may have damaged insulation. Sometimes the insulation inside an electrical tool or appliance is damaged. When insulation is damaged, exposed metal parts may become energized if a live wire inside touches them. Electric hand tools that are old, damaged, or misused may have damaged insulation inside. If you touch damaged power tools or other equipment, you will receive a shock. You are more likely to receive a shock if the tool is not grounded or double-insulated. (Double-insulated tools have two insulation barriers and no exposed metal parts.) You need to recognize that defective insulation is a hazard.

19. Grounding
When an electrical system is properly grounded, there is a path that allows the current to travel to the earth (the ground).
When any electrical system is
not properly grounded, a hazard
exists.
INSTRUCTOR’S NOTES:
When an electrical system is not grounded properly, a hazard exists. The most common OSHA electrical violation is improper grounding of equipment and circuitry. The metal parts of an electrical wiring system that we touch (switch plates, ceiling light fixtures, conduit, etc.) should be grounded and at 0 volts. If the system is not grounded properly, these parts may become energized. Metal parts of motors, appliances, or electronics that are plugged into improperly grounded circuits may be energized. When a circuit is not grounded properly, a hazard exists because unwanted voltage cannot be safely eliminated. If there is no safe path to ground for fault currents, exposed metal parts in damaged appliances can become energized.
Extension cords may not provide a continuous path to ground because of a broken ground wire or plug. If you contact a defective electrical device that is not grounded (or grounded improperly), you will be shocked. You need to recognize that an improperly grounded electrical system is a hazard.
(f) Grounding. Paragraphs (f)(1) through (f)(7) of this section contain grounding requirements for systems, circuits, and equipment.
(4) Grounding path. The path to ground from circuits, equipment, and enclosures shall be permanent and continuous.

20. Power Tools
Power tools that are damaged or not properly maintained can cause you to be seriously injured.
If you touch a metallic part of a power tool that is energized because of damaged insulation or improper grounding, you could be shocked.
INSTRUCTOR’S NOTES:
Hand-held electric tools present a potential danger because they make continuous good contact with the hand(s).
Metallic parts of electric tools and machines can become energized if there is a break in the insulation of their wiring. A low-resistance wire between the metallic case of the tool/machine and the ground – an equipment grounding conductor – provides a path for the unwanted current to pass directly to the ground. This greatly reduces the amount of current passing through the body of the person in contact with the tool or machine. Properly installed, the grounding conductor provides protection from electric shock.

21. Power Tools To protect you from shock, burns and electrocution, tools
must:
Have a three-wire cord with ground and be plugged into a grounded receptacle.
Be double insulated.
Be powered by a low-voltage isolation transformer.
INSTRUCTOR’S NOTES:
Wiring design and protection
(f)(5)(v)(C)(3)
(f) Grounding. Paragraphs (f)(1) through (f)(7) of this section contain grounding requirements for systems, circuits, and equipment.
(5) Supports, enclosures, and equipment to be grounded
(v) Equipment connected by cord and plug. Under any of the conditions described in paragraphs (f)(5)(v)(A) through (f)(5)(v)(C) of this section, exposed non-current-carrying metal parts of cord - and plug-connected equipment which may become energized shall be grounded.
[A] If in hazardous (classified) locations (see § ).
[B] If operated at over 150 volts to ground, except for guarded motors and metal frames of electrically heated appliances if the appliance frames are permanently and effectively insulated from ground.
[C] If the equipment is of the following types:
[1] Refrigerators, freezers, and air conditioners
[2] Clothes-washing, clothes-drying and dishwashing machines, sump pumps, and electrical aquarium equipment
[3] Hand-held motor-operated tools
[4] Motor-operated appliances of the following types: hedge clippers, lawn mowers, snow blowers, and wet scrubbers
[5] Cord- and plug-connected appliances used in damp or wet locations or by employees standing on the ground or on metal floors or working inside of metal tanks or boilers
[6] Portable and mobile X-ray and associated equipment
[7] Tools likely to be used in wet and conductive locations and
[8] Portable hand lamps. Tools likely to be used in wet and conductive locations need not be grounded if supplied through an isolating transformer with an ungrounded secondary of not over 50 volts. Listed or labeled portable tools and appliances protected by an approved system of double insulation, or its equivalent, need not be grounded. If such a system is employed, the equipment shall be distinctively marked to indicate that the tool or appliance utilizes an approved system of double insulation.
(vi) Nonelectrical equipment. The metal parts of the following nonelectrical equipment shall be grounded: frames and tracks of electrically operated cranes; frames of nonelectrically driven elevator cars to which electric conductors are attached; hand operated metal shifting ropes or cables of electric elevators, and metal partitions, grill work, and similar metal enclosures around equipment of over 750 volts between conductors.
Hazards of portable electric tools:
Currents as small as 10 mA can paralyze, or “freeze” muscles
- Person cannot release tool
- Tool is held even more tightly, resulting in longer exposure to shocking current
Power drills use 30 times as much current as what will kill.
Double-insulated equipment must be distinctly marked to indicate that the equipment utilizes an approved system of double insulation.

22. Overhead Power Lines
Overhead power lines are not usually insulated, and cause more than half of all electrocutions.
INSTRUCTOR’S NOTES:
Most people do not realize that overhead power lines are usually not insulated. More than half of all electrocutions are caused by direct worker contact with energized power lines. Power line workers must be especially aware of the dangers of overhead lines. In the past, 80% of all lineman deaths were caused by contacting a live wire with a bare hand. Due to such incidents, all linemen now wear special rubber gloves that protect them up to 34,500 volts. Today, most electrocutions involving overhead power lines are caused by failure to maintain proper work distances.
(c)(3).
(c) Working on or near exposed energized parts.
(3) Overhead lines. If work is to be performed near overhead lines, the lines shall be deenergized and grounded, or other protective measures shall be provided before work is started. If the lines are to be deenergized, arrangements shall be made with the person or organization that operates or controls the electric circuits involved to deenergize and ground them. If protective measures, such as guarding, isolating, or insulating, are provided, these precautions shall prevent employees from contacting such lines directly with any part of their body or indirectly through conductive materials, tools, or equipment.
Note: The work practices used by qualified persons installing insulating devices on overhead power transmission or distribution lines are covered by § of this Part, not by §§ through of this Part. Under paragraph (c)(2) of this section, unqualified persons are prohibited from performing this type of work.
(i) Unqualified persons.
[A] When an unqualified person is working in an elevated position near overhead lines, the location shall be such that the person and the longest conductive object he or she may contact cannot come closer to any unguarded, energized overhead line than the following distances:
[1] For voltages to ground 50kV or below - 10 feet (305 cm)
[2] 10 feet (305 cm) plus 4 inches (10 cm) for every 10kV over 50kV.
[B] When an unqualified person is working on the ground in the vicinity of overhead lines, the person may not bring any conductive object closer to unguarded, energized overhead lines than the distances given in paragraph (c)(3)(i)(A) of this section.
Note: For voltages normally encountered with overhead power line, objects which do not have an insulating rating for the voltage involved are considered to be conductive.
(ii) Qualified persons. When a qualified person is working in the vicinity of overhead lines, whether in an elevated position or on the ground, the person may not approach or take any conductive object without an approved insulating handle closer to exposed energized parts than shown in Table S-5 unless:
[A] The person is insulated from the energized part (gloves, with sleeves if necessary, rated for the voltage involved are considered to be insulation of the person from the energized part on which work is performed) or
[B] The energized part is insulated both from all other conductive objects at a different potential and from the person or
[C] The person is insulated from all conductive objects at a potential different from that of the energized part.

23. Wet Conditions
Wet conditions are hazardous because you can become an easy path for electrical current.
There are many circumstances that create wet conditions:
Standing in water
Wet clothing
High humidity
Perspiration
INSTRUCTOR’S NOTES:
Working in wet conditions is hazardous because you may become an easy path for electrical current. If you touch a live wire or other electrical component-and you are well-grounded because you are standing in even a small puddle of water, you will receive a shock.
Damaged insulation, equipment, or tools can expose you to live electrical parts. A damaged tool may not be grounded properly, so the housing of the tool may be energized, causing you to receive a shock. Improperly grounded metal switch plates and ceiling lights are especially hazardous in wet conditions. If you touch a live electrical component with an uninsulated hand tool, you are more likely to receive a shock when standing in water.
But remember, you don't have to be standing in water to be electrocuted. Wet clothing, high humidity, and perspiration also increase your chances of being electrocuted. You need to recognize that all wet conditions are hazards.

24. Safe Work Practices You can StartSafe and StaySafe by using
the following safe work practices:
Inspect cords before each use
Never overload a circuit
Stay away from all unguarded conductors
To unplug, pull on the plug, not the cord
Don’t wear jewelry or use other metal objects around electrical equipment
INSTRUCTOR’S NOTES:
OSHA’s electrical safety-related work practice requirements are contained in 29 CFR
Electrical accidents are largely preventable through safe work practices. As the instructor you may, at your discretion, include the following 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
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
Be Sure Plug And Receptacle Have Proper Mating Configuration
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

25. Safe Work Practices: Training
Training concerning electricity is very important. Training for employees working with electrical equipment must include how to:
De-energize the equipment
Use lockout and tag procedures
Use insulating protective equipment
Maintain a safe distance from energized parts
Use appropriate PPE
INSTRUCTOR’S NOTES;
OSHA’s electrical safety-related work practice requirements are contained in 29 CFR
All employees should be trained to be thoroughly familiar with the safety procedures for their particular jobs. Moreover, good judgment and common sense are integral to preventing electrical accidents. When working on electrical equipment, for example, some basic procedures to follow are:
• de-energize the equipment,
• use lockout and tag procedures to ensure that the equipment remains de-energized,
• use insulating protective equipment
• maintain a safe distance from energized parts

26. Safe Work Practices: Lockout/Tagout
When performing lockout/tagout on circuits, trained employees will do the following:
Turn off the power supply
Put a lock on all power sources to the circuit
Apply a tag
Test the circuit
INSTRUCTOR’S NOTES:
Emphasize to students the need for training before doing any work.
Lock-out/tag-out is an essential safety procedure that protects workers from injury while working on or near electrical circuits and equipment. Lock-out involves applying a physical lock to the power source(s) of circuits and equipment after they have been shut off and de-energized. The source is then tagged out with an easy-to-read tag that alerts other workers in the area that a lock has been applied.
Also, lock-out/tag-out prevents the unexpected release of hazardous gasses, fluids, or solid matter in areas where workers are present.
Deenergizing Electrical Equipment
The accidental or unexpected sudden starting of electrical equipment can cause severe injury or death. Before ANY inspections or repairs are made, the current must be turned off at the switch box and the switch padlocked in the OFF position. At the same time, the switch or controls of the machine or other equipment being locked out of service must be securely tagged to show which equipment or circuits are being worked on.
For more information on the Lockout/Tagout (LOTO) standard, , see the Lockout/Tagout Interactive Training Program at the osha web site, and find this reference under “OSHA Advisors”.

27. Summary
It is very important to StartSafe and StaySafe around electricity. In order to do so:
Know the hazards
Plan your work and plan for safety
Avoid wet working conditions and other dangers
Avoid overhead power lines
Use proper wiring and connectors
Use and maintain tools properly
Wear the correct PPE for the job