It has been more than 100 years since Thomas Edison commissioned the first electrical generating station in New York City. One might expect that we would know everything there is to know about electrical safety by now, yet our knowledge continues to grow.
Back in the very early days of electrical power systems, the basic electrical safety rule was “Don’t touch energized conductors.” That’s still good advice. However, electrical workers did not always follow this rule.
According to the 1942 edition of the “American Electrician’s Handbook,” a common method used to test for the presence of voltage was “by touching the conductors with the fingers.” The handbook then went on to explain that “this method is safe where the voltage does not exceed 250.” Apparently, not everyone could use this method because the book then described how “some men can endure the electric shock that results without discomfort, whereas others cannot.”
Back then, the arc flash hazard also was considered just another unavoidable job risk. It was understood that, if a worker made inadvertent contact between conductors, an electrical explosion may result that could injure or kill the worker.
Obviously, we have learned a few things since then.
Fast forward: Today’s electrical safety practices have come a long way and are based on nationally accepted and recognized standards, such as the Occupational Safety and Health Administration’s regulations, the National Fire Protection Association’s 70E and American National Standards Institute’s C2 National Electrical Safety Code.
Only qualified people, please!
To minimize the possibility of accidents from electrical hazards, only qualified people are permitted to perform work on or near energized electrical equipment. This “on or near” is referred to as the limited-approach boundary, which NFPA 70E defines as the distance from exposed energized conductors where a shock hazard exists.
NFPA 70E defines a qualified person as “One who has the skills and knowledge related to the construction and operation of the electrical equipment and installations and has received safety training to recognize and avoid the hazards involved” (emphasis added).
10 key components of an electrical safety training program
Setting up a proper safety training program may seem daunting. Where do you start? Although there are many different components that can make up an electrical safety training program, the following are the 10 most important ones.
Identify the hazards
Electrical safety begins by being able to recognize and avoid possible hazards. Once identified, the hazards can be eliminated, reduced or avoided. Part of the electrical safety training program is to learn what each hazard is and what effect it could have on the worker.
The first and most obvious hazard is electric shock and electrocution. When contact is made with energized conductors, current can pass through the body. Depending on the amount of current and path it takes through the body, a person could experience anything from a minor tingling sensation to severe pain, respiratory paralysis or ventricular fibrillation.
The arc flash hazard can result in the release of a tremendous amount of thermal energy that can cause substantial burn injury and even death. An arc flash also can produce other hazards, such as blast pressure, ultraviolet light, shrapnel and potentially toxic vapors. Each of these hazards must be identified and addressed as part of safe work practices training.
Shock hazard analysis
As part of the process for identifying the hazards, NFPA 70E requires that a shock hazard analysis must be performed. This requires determining the voltage to which a person may be exposed, defining the boundary requirements and selecting the proper personal protective equipment necessary to minimize the possibility of electric shock.
The boundaries include the limited-, restricted- and prohibited--approach boundaries. A necessary part of the training includes developing an understanding of what each of these are used for and knowing what protection and actions are required for work within each boundary.
Arc flash hazard analysis
To identify and protect the worker from the arc flash hazard, NFPA 70E requires performing an arc flash hazard analysis. The first step requires determining the arc flash boundary at the equipment location. This boundary is defined as the distance from a prospective arc flash source where the incident energy drops to 1.2 calories per centimeter squared (cal/cm2). The value of 1.2 cal/cm2 is the energy that can result in the onset of a second-degree burn, which is generally considered the standard for protection.
When an arc flash occurs, the incident energy decreases rapidly with distance from the arc. Standing closer than the arc flash boundary can significantly increase the incident energy exposure if an arc flash occurs.
The second part of the analysis is to select appropriate arc rated protective clothing and personal protective equipment. This protection is worn when working within the arc flash boundary and an arc flash hazard exists.
There are several methods that can be used for selecting the appropriate protection. An arc flash hazard calculation study can be performed to calculate the prospective incident energy. Calculations are typically based on IEEE 1584—IEEE Guide for Performing Arc-Flash Hazard Calculations, with the results used for selecting the appropriate protective clothing and equipment.
As an alternative to calculations, NFPA 70E contains tables that specify the required category of protection based on the task being performed and the electrical equipment involved. Care must be taken when using the tables since there are limitations of maximum short circuit current and protective device clearing time. Training would cover all these topics.
Electrically safe working condition
Energized electrical work should always be a last resort. Electrical systems should be placed into an electrically safe working condition. There are only a few exceptions to this requirement, such as testing, troubleshooting or infeasibility.
This process requires performing actions, such as determining all electrical sources that supply the equipment. Once identified, disconnects for each source are opened, and lockout/tagout methods must be used. Proper protection must be used throughout this process, and only when the circuit is verified to have an absence of voltage by using an appropriate voltage detector and test methods is it considered to be electrically safe. Workers must learn how to establish an electrically safe working condition.
Workers that could be exposed directly or indirectly to sources of electrical energy must be trained on how to perform lockout/tagout operations. Lockout/tagout requirements are defined by OSHA and NFPA 70E and are an integral part of establishing an electrically safe working condition.
Energized electrical work permit
If energized electrical work is to be performed and an electrically safe working condition cannot be established (it’s infeasible or doing so would create a greater hazard), an energized electrical work permit is required. There are a few exceptions to the permit, such as testing, troubleshooting and voltage measurement. This written permit must have the approval and signature of a designated person. The training program should illustrate how and when to complete this important document.
Understanding arc flash warning labels
Arc flash warning labels can contain valuable information for use by the qualified electrical worker. Training should include how to interpret and correctly use the information on the label. NFPA 70E requires the minimum arc rating of protective clothing or the calculated incident energy to be listed on the label. In addition, the voltage, date of the study and arc flash boundary also must be included. The limited, restricted and prohibited approach boundaries, working distance and other information is frequently added as well.
Safe work practices
Safety-related work practices and procedures must be an integral part of the safety training program. These practices are necessary to provide protection from the electrical hazards associated with specific jobs or tasks. A person can be trained and qualified for some tasks but not others and, therefore, may not be qualified for all assignments.
Worst-case scenario training
Even with proper training and the use of safe work practices, accidents still happen. It takes very little current traveling though a person’s chest to stop their breathing or throw them into ventricular fibrillation. In situations like this, immediate action is required if there is to be any chance of survival.
People that are responsible for emergency actions are required to be trained to perform cardiopulmonary resuscitation and release and rescue methods. As of the 2012 edition of NFPA 70E, training is also required for the use of an automatic external defibrillator (AED).
Repeat the process
Electrical safety has evolved since the 1942 “American Electrician’s Handbook” was published. In fact, because electrical safety practices continue to improve, we know more about electrical safety now than we did just a few years ago. New types of equipment and technology are emerging all the time. Beginning with the 2012 edition, NFPA 70E requires retraining at a maximum interval of every three years.
Your permanent record
“This will go on your permanent record.” Many of us have heard that line before. Usually, it is meant as a threat for undesirable behavior, but successful completion and demonstrated competence of electrical safety training also must go into an employee’s file. Keeping these records is important since it provides a historical record of the worker’s training. It also can be invaluable during an accident investigation. When I have been called as an expert witness in injury cases, one of the first questions asked is “was the employee qualified?” Having this record can help establish that fact.
As part of the recordkeeping process, the 2012 edition of NFPA 70E will require that the content of the training be documented. This way the content can be reviewed and compared to the goals and objectives of the company’s safety program.
If you or your staff have not been through electrical safety training in the past three years, today would be a good day to begin making plans to do so.
PHILLIPS, founder of www.brainfiller.com and www.ArcFlashForum.com, is an internationally known educator on electrical power systems and author of “Complete Guide to Arc Flash Hazard Calculation Studies.” His experience includes industrial, commercial and utility systems, and he is a member of the IEEE 1584 Arc Flash Working Group. Reach him at firstname.lastname@example.org.