Fact: One person is electrocuted every day in the workplace.
Fact: More people in the 25- to 44-year-old age group are electrocuted in the workplace than any other age group.
The above statistics are sobering, surprising, and worrisome. Every employer wants to protect their employees in the work environment, but it is often a matter of “how can we make the workplace safer” rather than “do I really need to make it safer.” Employers will do what they can to ensure workers are safe, and they want to know what can be done to make that happen.
This article covers seven habits that will make the workplace safe for electrical work. The article is far too short to be specific, but it covers the topic in general based on the authors’ training and accident investigation experience. It helps set the direction and closes with several specific steps an employer can take to make the workplace electrically safer. Statistics show that if these seven electrical safety habits are followed, electrical incidents are greatly reduced if not eliminated.
Habit 1 – Always Verify Absence of Voltage and Use Insulating Gloves and Tools
This habit is listed first because it is crucial. No one should even consider touching any circuit part or conductor unless they have verified that it has no voltage on it. Follow the routine “test before touch” using the “live-dead-live” rule. First, apply a voltage tester to a known live circuit and verify that the tester reads voltage. Then test the circuit part or conductor that will be worked on. To make certain the tester is still functioning, again apply the tester to the original known live circuit and verify it is still functioning.
The second part of this habit is to always use insulating gloves. This does not mean leather gloves, but rubber insulating gloves that are the proper voltage class and have been tested (testing must occur after six months of use or one year if the gloves are stored properly). A corollary to this habit is using insulating tools when tools may make accidental contact with circuit parts or conductors that may be energized.
Habit 2 – Establish Boundaries for Worker Safety from Shock and Arc Flash Hazards
Employers should use the available national consensus standards published by the National Fire Protection Association (NFPA). They publish two standards particularly addressing electrical hazards.
The first standard is NFPA 70, the National Electrical Code (NEC). This standard addresses the design, installation, and inspection of electrical equipment and systems. The second standard is NFPA 70E, the Standard for Electrical Safety in the Workplace. For example, to find the working space required around electrical equipment, employers can check the NEC. To find the shock and arc flash protection boundaries, check the 70E standard. The NEC requires equipment be labeled for arc flash and shock hazards.
Shock protection boundaries are determined by the voltages encountered while arc flash protection boundaries are determined by the amount of energy available to the electrical equipment and the time the arc flash will take to clear. The arc flash boundary is the distance where unprotected skin may experience the onset of second degree burns during an arc flash incident. At or below 600 volts, if the power distribution meets certain criteria, employers can use four feet for the arc flash protection boundary.
Habit 3 – Always Wear Arc-rated Daily Wear and a Face Shield
References to arc-rated clothing may be in terms of flame resistant clothing, but not all flame resistant clothing is arc rated. When verifying that flame resistant clothing is arc-rated, check for a calorie per cubic centimeter squared (cal/cm2) rating, a hazard/risk category rating, and a reference to ASTM International F1506 standard. If it doesn’t have any or at least one of these statements on the clothing tag, it may not be arc rated. All arc-rated clothing is flame resistant but not all flame resistant clothing is arc rated.
Common cotton clothing and clothing made of poly-blends is not arc rated or flame resistant. Chances of surviving body burns are dramatically increased using arc-rated clothing. Studies of electrical arc flash incidents have shown that the worse incidents were caused by clothing catching fire. Other studies confirm that it is less costly to dress employees in arc-rated clothing than paying for their recovery medical costs. Wearing cotton undergarments is acceptable in many cases but arc-rated undergarments are available. Undergarments or any garments worn under arc-rated clothing that are a poly-blend or made of synthetic melting materials are expressly prohibited in NFPA 70E and in Occupational Safety and Health Administration (OSHA) Standards, 29 Code of Federal Regulations, Part 1910.269, Electric Power Generation, Transmission, and Distribution.
Habit 4 – Always Use a GFCI with Cord- and Plug-connected Tools and Extension Cords
This habit is expressly stated in OSHA standards and became law in 2008 for all maintenance and construction work (Part 1910.304(b)(3)(ii)). Even more, since the human body is so sensitive to electrical current flowing through it, it is recommended that all persons handling cord- and plug-connected tools use leather gloves.
Habit 5 – When Feasible, Create an Electrically Safe Work Condition
NFPA’s 70E is very specific on this topic. Article 120.1 on page 19 of the standard describes the process in detail, which has been summarized below using the acronym ISOLATE:
I – Identify all energy sources and check drawings
S – Shut down sources feeding equipment
O – Open disconnect switch or circuit breaker
L – LO/TO, which means apply lockout/tagout devices
A – Assure contacts are open, visually when possible
T – Test/Verify all phase and neutral zero/test tester
E – Employ safety grounds for high voltage where necessary
These steps are clear and necessary to establish an electrically safe work condition, yet keep in mind three issues when considering this process.
1. The process of creating an electrically safe work condition is dangerous. Approaching circuit parts or conductors that may be energized is inherently unsafe. Electrical hazards are not visible to the naked eye.
2. Wearing the proper personal protective equipment (PPE) does not create an electrically safe work condition. In fact, PPE is not even mentioned in the seven steps listed above. The process assumes the person establishing an electrically safe work condition is wearing the appropriate PPE until the process is complete.
3. The evaluation of every electrical incident will ultimately find that one of more of the steps listed above was not completed. Electrical incidents are preventable. Establishing an electrically safe condition eliminates shock and arc flash hazards.
Habit 6 – Identify Higher Hazard Levels and Adopt Proper PPE or Engineering Controls to Mitigate Those Hazards
The most common “greater hazard” is arc flash. NFPA 70E has several articles that require a shock and arc flash hazard analysis be performed (Article 110.8 and 130.3). Typically, the employer retains a firm that performs the analysis, gathering data and using computer software to analyze the hazards. NFPA 70E provides for two exceptions to performing calculations. The first is an arc flash hazard analysis does not need to be performed for circuits that are 240 volts or lower and the transformers supplying those circuits are less than 125 kilovolt ampere.
The second exception is when the employer chooses to use the tables contained in 70E. If so chosen, the electrical power distribution systems need to meet certain criteria as listed in the 70E standard footnotes.
After the analysis by any of the above methods, the employer shall label the electrical equipment giving warnings regarding the hazards. The NEC and NFPA 70 require all electrical equipment be labeled with a warning stating that an electrical arc flash hazard exists and recommends using the NFPA 70E process. NFPA 70E requires that the label include the arc flash exposure be stated in cal/cm2, or the hazard/risk category of clothing stated in 0-4, or both.
Label requirements in 2011 are expected to increase with a little more detail.
Habit 7 – Measure, Audit, and Continuously Improve Electrical Safety Processes
Obviously, implementing electrical safety habits will not be successful unless someone follows up and makes certain proper and safe activities happen. NFPA 70E requires annual auditing of electrical safety practices in the workplace by management or someone delegated by management. Optimizing the hierarchy of your controls will ensure an effective electrical safety program.
• Eliminate the hazard by de-energizing, then locking and tagging out the circuit parts or conductors. Then visualize and verify that, indeed, the circuit parts and conductors are de-energized.
• Use engineering controls and design out and remove the exposure to the hazard.
• Use administrative controls and perform labeling, training, safe work practices, and work plans, and establish a live electrical work permit program.
• Provide and use PPE.
Below is a list of steps that establish a basis and encourage implementing the seven electrical habits listed above.
1. Attend NFPA 70E training.
2. Provide 70E training for employees.
3. Update single-line drawings.
4. Conduct a hazard analysis study.
5. Label equipment.
6. Select the appropriate PPE.
7. Develop an electrical safety program.
8. Audit for compliance.
9. Review program annually.
10. Determine a hazard mitigation strategy.
Practicing the seven electrical safety habits will go a long way in making a workplace safer.
About the Authors: Al Havens has more than 40 years of electrical safety experience, 26 of which as senior electrical engineer for U.S. Gypsum. He currently provides instruction in the application and use of the NFPA 70E standard in both low- and high-voltage environments.
Hugh Hoagland is among the world’s foremost experts on electrical arc testing and safety. He has helped develop most of the arc-resistant rainwear used in the world today as well as creating the first face shield to protect against electric arcs. Hoagland sits on several electrical industry committees, is a featured speaker at safety conferences and events, and provides training and consulting.
Tech Topics – October 2010 RENDER | back