Electrical Safety. Facilitator Guide

Transcription

1 Electrical Safety Facilitator Guide

2 Contents Overview Tips For Conducting An Effective Training Session Successful Safety Programs Program Objective What is Electricity? How Does Electricity Work? Electrical Hazards Personal Protective Equipment Safe Work Practices Fundamentals of Grounding Determining Energized Parts Determining Nominal Voltage Lockout & Tockout Procedures Equipment Start-Up & Operation Summary Quiz SUMMIT TRAINING SOURCE INC.All rights reserved. No part of this book may be reproduced in any form or by any means without written permission from Summit Training Source Inc. If you wish to purchase additional copies, please call our office at

3 Overview Summit Training Source s Electrical Safety training series is designed to comply with OSHA s Electrical Safety-Related Work Practices Standard. The standard addresses non-electrician employees who are exposed to potential electrical hazards in the performance of their job. Electricity is the No. 1 cause of work place fires. According to National Safety Council statistics, an average of 805 people have been electrocuted annually over the past three years.thousands more suffer disabling injuries due to accidental contact with electricity. In a government study, the No. 1 cause of work related electrocutions was contact with overhead lines. Because of this, the standard calls for specific safe clearance distances from overhead lines. The standard distinguishes between qualified and non-qualified employees. All employees who face a risk of electrical shock that is not reduced to a safe level by electrical installation requirements must be trained on the hazards associated with electricity and the safety related work practices that pertain to their respective assignments. In addition, qualified employees - those permitted to work on or near exposed energized parts - must be trained on the skills and techniques to distinguish energized parts from other parts of electrical equipment, the skills and techniques to determine nominal voltage, and the appropriate clearance distances for the respective voltages. The Facilitator s Guide and videotapes provide you with the material necessary to conduct an interesting and informative safety meeting on Electrical Safety. Tips for Conducting an Effective Training Session Preview the programs to become familiar with the content of the videotapes. Review the print material. Prepare a short introduction to introduce the program to the group you are training. Check the room where the training will be held to make sure there are enough chairs and space for everyone. Make sure the appropriate video equipment, writing instruments, and other supplies are available. Check for scheduling conflicts. Prepare discussion topics specific to the group attending the training session. Include examples of unsafe actions or hazards associated with their job function. When asking questions, wait for a response before moving to another topic. Use the person s name when responding to them. Learning is enhanced by participated. Be receptive to responses and questions. Invite people to participate. Speak in a normal tone. maintain eye contact with the group. Successful Safety Programs Companies with outstanding safety records have two main things in common: A positive attitude towards safety A strong commitment from management Safety starts at the top. It must be incorporated in every decision management makes. Successful companies realize the benefits associated with safe production and make it a part of every function. They view safety as a positive tool necessary for efficient operations. No tasks are performed that cannot be executed in a safe and proper manner. When management makes safety a priority, their subordinates make it a priority. Safety becomes a part of every task performed. Safety is a self-perpetuating mechanism. When management makes a strong commitment to safety, the workers own safety awareness is increased. When employee safety awareness is increased and supported by management, a reduction in unsafe behavior and conditions are often the results. Reducing unsafe behavior and unsafe conditions is essential to creating an accident-free environment. Companies who possess a positive safety attitude and a strong commitment from management have found their efforts rewarded with increases in production, quality and morale, and a reduction in accidents and their associated causes. Program Objective The objective of this program is to eliminate electrical-related accidents and injuries in your facility by: Improving your workers awareness and respect of what electricity is and its potential hazards Reviewing skills and techniques to perform safe work practices Stimulating participation and discussion on electrical safety-related work activities that the worker will retain and use both on and off the job. 4 5

4 Introduction What is Electricity? Electricity is our most valuable energy resource. Though we use it everyday, few people really understand what electricity is and how it works. Even more important, most people do not have a respect or complete understanding of its potential hazards. Electricity is an energy source created by the imbalance of electrons and protons in the atom. It is the combination of a force called voltage and the movement of invisible particles known as current. Electricity is the number one cause of fires in the work place. More than 800 people are electrocuted each year. Thousands more suffer disabling injuries from accidental contact with electricity. More than half of these accidents involve the same common low voltage you use in your home. Because of these alarming statistics, federal regulations have been established to train you on the hazards of electricity and safe work practices you can use when working with or near electricity. All materials contain electrons and protons. This paper, for instance, has electrons and protons in it. But there is no electricity in it because the number of electrons equals the number of protons. Power Generating Facility In this training program you will learn... Voltage Increased The fundamentals of electricity Its associated hazards Safe work practices to ensure your safety and that of your co-workers. The information you learn will have valuable applications both on and off the job. With a knowledge of how electricity works and a respect for the potential hazards, you can prevent electrical accidents from occurring in your facility. Voltage Reduced Most of the electricity we use in our homes and at work is generated in a power station. At the power station, fuel such as coal or oil is used to heat water and turn it into steam. The steam pushes a wheel called a turbine at high speeds. The turbine moves a generator which makes electricity. The electricity is carried away from the power plant along thick wires called cables. To send the electricity over long distances, the voltage is increased by transformers. (Voltage is the pressure or force that pushes the electricity.) When the electricity reaches towns or cities, the voltage is reduced by another transformer for our use. 6 SUMMIT TRAINING SOURCE INC. SUMMIT TRAINING SOURCE INC. 7

5 How Electricity Works Electrical energy provides light, powers, equipment, and transmits sounds by either generating heat or creating a magnetic force. A common analogy used to describe the basic principles of electricity is water. Electricity travels through a system of wires much like water travels through a pipe. A unique difference between the two is if the water pipe breaks, the water will continue to flow, spilling out of the end of the pipe; if the wire is broken, the electricity will not flow out of the wire. But it will still continue to flow to the broken end of the wire. Wires provide a path for electric current to travel through just as pipes provide a path for water. Metals, such as copper and aluminum, are used to manufacture electrical wires because they are good conductors of electricity. That is, they are good channels for transmitting an electric charge. Most non-metals, such as rubber and plastics, are poor conductors of electricity. They are often referred to as insulators. Insulators are resistant to electricity and help to keep electric current on its path. Name three examples of conductors of electricity Electricity needs a complete circuit to flow. A circuit is a path that returns to its power source or point of origin. A broken wire, loose connector, or a switch in the off position is not a complete circuit and will prevent the flow of electrical current. 3. POSSIBLE ANSWERS: aluminum, water, steel, copper, mercury, human body Name three examples of poor conductors of electricity POSSIBLE ANSWERS: plastic, rubber, glass, wood, ceramic 8 9

6 Electrical Hazards There are three basic types of electrical hazards: Fire Shock Burns Factors that affect the seriousness of the injury include: The type of circuit and its voltage Resistance and amperage The path the current takes through the body The length of contact with the energized source Fires Electricity is the number one cause of fires in the work place. Three ingredients are necessary for a fire to exist: Oxygen Fuel Heat HEAT Electricity is the number one cause of fires in the workplace. OXYGEN FUEL Contact with overhead power lines is the No. 1 cause of electric shock in industry and the main cause of electrocutions. Four other common causes of electrical shock in the work place include: Failure to lockout electrical systems for maintenance and repairs Failure to ground Defective equipment and lines Wet electrical equipment Electricity generates heat. Engineering controls, such as fuses, circuit breakers, ground fault circuit interrupters and insulators, are designed to prevent electricity from becoming the heat source for fires. What safe work practices can be used to prevent electrically related fires? Inspect tools, equipment, cords Good housekeeping (remove potential fuel source(s) Perform maintenance on equipment Do not overload circuits and outlets Do not operate equipment over capacity Proper tool selection Below are the effects of contact with common 60 hertz AC current. 1 milliamp (ma) Usually harmless, but the slight tingling or involuntary movement to the shock could cause you to lose your balance and be injured in a fall ma May result in a loss of muscle control. This may cause you to not be able to let go of the source of shock and could potentially increase the degree of injury ma Strong enough to cause death amps Can cause internal organ damage and internal and external burns. Cardiac arrest and respiratory failure may occur. Electric Shock Electrical shock occurs when the body comes in contact with the flow of electricity. You do not have to have direct contact with an exposed live wire for this to happen. If a conductive material such as the boom of a truck or mobile crane comes in contact with an overhead power line and you touch the vehicle while on the ground, you could be shocked. Accidental contact with electricity can cause a variety of health consequences varying from minor tingling to internal organ damage, burns, and even death

7 Electrical Hazards (continued) Personal Protective Equipment The following chart shows the approach distances for qualified persons. Table S Approach Distances For Qualified Employees Alternating Current Voltage range (phase to phase) Minimum approach distance 300V and less avoid contact Over 300V, not over 750V...1 ft.(30.5 cm) Over 750V, not over 2kV...1 ft.6 in.(46 cm) Over 2kV, not over 15kV ft.(61 cm) Over 15kV, not over 37kV ft.(91 cm) Over 37kV, not over 87.5kV ft.6 in.(107 cm) Over 87.5kV, not over 121kV ft.(122 cm) Over 121kV, not over 140kV ft.6 in.(137 cm) Burns There are three basic types of burns suffered in electrical accidents: electrical burns, arc burns, and thermal contact burns. Electrical burns happen when electric current flows through the body. These burns are slow to heal. Arc burns are produced by electric arcs or by explosions close to the body. They can be fatal at distances up to 5 feet and can cause serious burns up to 10 feet. Finally, thermal contact burns can happen when the skin contacts hot surfaces such as overheated electric conductors, conduits, or other energized equipment. Since the body is a conductor of electricity, the proper selection and use of nonconductive personal protective equipment is very important when working with or near electricity. Which of the following personal protective equipment is required at your facility? LEATHER GAUNTLET GLOVES OVER RUBBER INSULATED GLOVES -- rubber is a non-conductive material. The leather protects the rubber from tears and other damage. HARD HATS -- Non-metal hard hats should be worn whenever there is the potential of a bump hazard or your head coming in accidental contact with an energized source. EYE PROTECTION -- Safety glasses should be worn at all times in the work environment. Side shields are strongly recommended. Filtered eye protection must be worn when working with electrical arcs such as welding. RUBBER OR NON-CONDUCTIVE CLOTHING -- Metal belt buckles, buttons, and certain synthetic fibers will conduct electricity. Natural fibers such as cotton should be worn. Additional protection, such as rubber sleeves, should be worn when working near exposed energized parts. RUBBER-SOLED SHOES OR BOOTS WARNING! Metal jewelry such as watches, rings, key chains and earrings should never be worn when working around exposed energized parts. The metal objects could cause serious burns to the skin if accidental contact is made with an energized electrical source. While wearing the proper personal protective equipment is an important and necessary preventive measure, it does not make you immune from electrical hazards. That's why safe work practices are essential to ensure your safety

8 Safe Work Practices The most effective way to avoid accidental contact with electricity is to de-energize the system you are working on or maintain a safe distance from energized parts. Overhead Power Lines Federal regulations require you to keep minimum distances from unguarded, energized, overhead power lines. The distance requirements are based on the nominal voltage. When Using Electrically Powered Tools Inspect the tool before use. Check the cord for signs of defect. Use permanent wiring whenever possible. Avoid using electrical tools in wet conditions. Use only spark proof tools in highly combustible areas. Unqualified persons working near overhead power lines, either on the ground or in an elevated position, must keep a minimum 10-foot clearance from overhead power lines of 50kV or less. This distance includes any conductive object the person may contact. For voltages to ground over 50 kv, the distance increases 4 inches for every 10kV over 50kV. So if a power line is 60kV, you would need to keep a distance of 10 ft. 4 in. The clearance distance for vehicles and mechanical equipment is also a minimum of 10 feet. Other safe work practices you can follow include: When Using Extension Cords Make sure the cord is rated for the load it will carry. Inspect the cord for signs of defects such as fraying. Ground fault interrupts should be used when possible. Never drape the cord over metal ductwork or piping. Never alter a cord to perform a task. Never remove the grounding prong to fit the plug into a two-pronged receptacle. When Working with or Around Electrical Equipment Make sure all guards are properly in place. Make sure all electrical equipment and systems are grounded. Keep the equipment lubricated and well maintained. Never bypass built-in safety features. Practice good housekeeping procedures. Report any malfunctions immediately. Other Safe Work Practices Using non-conductive ladders around electrical equipment. Never exceed the capacity by overloading circuits. Never reach blindly into an electrical cabinet. Use illumination when needed. Secure doors or openings that could bump you into an energized part. Be aware of all energized electrical parts in your area. Use the proper tools. Always make sure your hands are dry when plugging and unplugging energized plugs and receptacles. Know and use lockout and tagout procedures. Respect the potential electric hazards

9 Grounding Grounding is another protective measure to prevent accidental contact with electricity. It is normally considered a secondary form of protection. Grounding ensures there is a path of low resistance to ground if there is an electrical equipment failure. Determining Energized Parts To be designated as a qualified person, you must have the skills and techniques necessary to determine if a part is energized. This can be done by visual inspection. How Does Grounding Work? Grounding is done by connecting all the non-current carrying metal parts together and then connecting them to the ground. It is important that the grounding conductor is firmly attached. Is the circuit open or closed? Are there any visible indicators that the system is energized? Are there any audible indicators? If equipment fails, the electricity will take the path of least resistance. In equipment that is grounded, the current would take a path through the ground wire rather than through the person touching the failed equipment because the human body is more resistant to electricity than the ground wire. A probe indicator may also be used to determine if a part is energized. Touch the conductive end of the probe to the part in question. If the probe light illuminates, the part is energized. When inspecting your equipment, make sure it is properly grounded. Without proper grounding, a person could become the path to ground if he or she touches the equipment. A ground wire will not protect you if you come in contact with an exposed energized part. 16 SUMMIT TRAINING SOURCE INC. SUMMIT TRAINING SOURCE INC. 17

10 Determining Nominal Voltage Lockout & Tagout Procedures A qualified person must also have the skills and techniques necessary to determine the nominal voltage of exposed live parts. This can be done in two ways: mathematically or with a volt meter. The volt meter is the more practical and common way to determine the nominal voltage. To use the volt meter: Set the range switch to the proper setting. If the anticipated voltage falls between two settings, select the higher setting. If the voltage is not known, always start at the highest setting. Attach the ground terminal to either the ground wire or a grounded surface. Touch the probe to a conductive point on the part being measured. Check the reading to determine if any adjustments need to be made to the range setting. The nominal voltage may also be computed mathematically if you know the amperes and ohms. AMPERES X OHMS = VOLTAGE By de-energizing a system and then locking and tagging it out before beginning work, you can avoid accidental contact with energized parts. Proper lockout and tagout procedures include: Identify all sources of energy to the circuit or equipment and properly disconnecting them. Release stored electrical energy which might endanger personnel. Release or block all stored nonelectrical energy that could accidentally energize the system. Apply a lock and tag on each disconnecting means to prevent accidental release or startup. The tags used will warn against unauthorized operation of the disconnect means and removal of the tag. If a tag is used without a lock, use additional safety measures such as removing an isolating circuit element, blocking a controlling switch, or opening an extra disconnecting device. Verify that all energy sources have been isolated and the proper equipment is locked out

11 Lockout & Tagout Procedures (continued) A qualified person must verify that the equipment cannot be restarted after the energy has been disconnected, locked and tagged out. Test equipment must be used to verify that all parts of the circuit which employees will be exposed to are deenergized. Test equipment should be checked before and after each use if voltages over 600 volts are involved. NEVER attempt to bypass or energize a system with a lock and tag on it without first checking with the person the lock and tag belongs to and having that person properly remove the lock and tag. Equipment Startup and Operation To re-energize the equipment, a qualified person must verify that all tools, jumpers, grounds, and other devices have been removed and all guards have been properly reinstalled. All workers exposed to the hazards of re-energizing the equipment must be warned and maintain safe clearance distances. All control buttons must be in the neutral or off position. ONLY the person who placed the lock may remove it. If that person is not available to remove it, procedures outlined in your written plan must be followed for removing the lock. Once locks and tags are removed, a visual check is required to make sure employees are clear of the circuits and equipment. Electrical Safety Quiz Name Date 1. A person needs to have direct contact with an overhead power line to receive a shock great enough to cause death. A person can be touching a conductive material which contacts an overhead line, and then receive a shock 2. The human body will conduct electricity. 3. Unless qualified, all workers must maintain a minimum 10 foot clearance distance from all overhead lines. 4. The best way to avoid accidental contact with electricity is to either maintain safe clearance distances or de-energize the system. 5. Grounding is considered a primary means of protection. Grounding is considered a secondary means of protection. 6. A qualified person must verify all lockout and tagout procedures performed on electrical equipment. 7. Poor housekeeping is a contributing cause to many electrically related fires. 8. Rubber, plastic, and glass are poor conductors of electricity

12 9. The three primary hazards of electricity are fire, shock, and electro-radiation. The three primary hazards are fire, shock and burns. 10. The number one cause of electrocution in the work place is contact with overhead lines. 11. Using an electrical tool with wet hands, even from heavy perspiration, increases your risk of receiving an electrical shock. 12. An aluminum extension ladder can be used within 5 feet of overhead power lines as long as the person does not climb within 10 feet of power lines. All conductive material must maintain a 10-ft clearance distance. 13. Electricity needs a complete circuit to flow. The human body is capable of completing the circuit. 14. All employees who work near electrical equipment need to be familiar with their company s lockout and tagout procedures, even if they do not actually perform the tasks themselves. 15. All cords should be inspected before use. 22

13 The Peak of Excellence Horizon Drive SE, Grand Rapids, MI (616) (800)