Arc Flash Events

An arc flash is one of the most dangerous electrical hazards to all employees working within an electrical hazard zone. Unfortunately, they’re also quite common. Five to ten arc flash events occur in the United States on a daily basis, with 30,000 arcs flashes occurring annually. Between their common occurrence and extreme danger levels, arc flashes account for nearly 80 percent of all accidents, incidents and fatalities among even highly trained industry employees — resulting in over 7,000 burn injuries annually, 2,000 of which require hospitalization.

Fortunately, the occurrence of arc flashes and electrical accidents in general has steadily gone down over the past few decades. This is primarily due to improvements in electrical education, more stringent preventative measures and better quality equipment. Today, it’s imperative for every person working in the industrial sector to be aware of the dangers of arc flashes and how they can happen, so they can better prepare for an arc flash event.

What Is an Arc Flash Event?

Essentially, an arc flash is an event where an electric current leaves its path to travel through the air. The stray arc usually passes from one conductor to another or to the ground, taking the path of least resistance. This could mean the current passes through an unintended piece of equipment or even a person, resulting in electrocution. The most problematic side effect of these events, however, is arc flash energy.

Most people have seen an arc flash before, in the form of an incandescent light bulb burning out. When the filament in a bulb breaks, the electricity running through the filament continues running through the air, creating an arc that appears as a blue flash of light. While events like these are very small, other events can be substantially larger, depending on the amount of current. Some industrial settings use huge amounts of current, releasing lethal amounts of energy when an arc flash occurs.

Some events can cause the surrounding air to reach temperatures of up to 35000 degrees Fahrenheit

As an arc flash passes through the air, this huge amount of energy ionizes the surrounding air, causing molecules in the air to energize and produce heat. Some events can cause the surrounding air to reach temperatures of up to 35,000 degrees Fahrenheit, which is actually hotter than the surface of the sun. Those temperatures can set fire to clothing, burn skin, liquefy metals and ignite nearby combustible materials within a second, even from a distance. At exposure under ten feet, such temperatures cause fatal burns and instantly vaporize many materials.

Arc flashes also produce other harmful environmental changes, including the following:

  • Pressure Wave: As the temperature increases around the flash arc event, the molecules in the air and surrounding materials react by heating up and expanding in volume. This change in volume creates a massive wave of pressure, often producing more than 2,000 pounds per square foot. This pressure can be enough to throw objects and people across a room, resulting in equipment damage and injury. It’s even enough to collapse lungs and break bones. Additionally, the pressure can throw melted materials, like molten metal, around the area up to a distance of 10 feet, causing additional damage and injury to people and equipment.

  • Sound Blasts: The sudden pressure change produced by an arc flash can also result in a sound blast, which can be enough to break glass and damage workers’ ear drums, resulting in hearing loss.

  • Bursts of Light: The explosion from an arc flash produces light as well as heat. This light is extremely bright, and it is enough to cause temporary blindness by itself.

What Causes an Arc Flash Event?

The cause of an arc flash is usually a short circuit of some kind, also called a fault condition. The cause of such a short can be one of many things. Just a few examples include:

  • Human Error: Many people develop lazy workarounds and habits when they’ve worked a job for a while, bypassing safety standards and procedures for those few seconds of saved time. Still other people get distracted while they work, resulting in forgetfulness or clumsiness. Such habits and mistakes include anything from misplacing or dropping a tool to skipping a maintenance step. When working with electrical devices, such mistakes can be enough to trigger an arc flash or other electrical emergency.

  • Neglected Maintenance Processes: Too much dust and debris building up on equipment can cause some serious functional problems. The same can be said for corrosion and condensation on electronic components. Failing to maintain electronic equipment in industrial settings can lead to any of these problems, each of which can result in a fault.

  • Improper Electrical Design: Improper installation is another common problem leading to arc flashes. Such installation issues could be a problem in the design or an old or improperly rated piece of equipment These system design problems increase the chances of a fault occurring, potentially resulting in an arc flash.

The resulting arc flash can vary in size and energy based on numerous variables, like amperage, voltage, the size of the arc gap and the space in which the flash takes place. However, you’ll notice that each one of these arc flash causes is largely avoidable. This is why OSHA and other worker safety programs focus so much on quality electrical hazard training.

What Are the Different Kinds of Arc Flash Events?

Four types of arc flash events are arc in a box, open air arc, ejected arc, tracking arc

Arc flash events have multiple causes and can occur in a wide variety of settings, so it makes sense that arc flashes come in different forms. In fact, there are four specific kinds of arc flash events recognized by professionals in the field. These arc flash types are:

  • Arc in a Box: Also called a confined flash, this type of arc flash is one that comes from a distribution or motor control box. Instead of being open on all sides, the flash is contained on all sides except the front opening. This causes all the energy to escape through the opening of the box. Most arc flash calculations use the arc in a box as a standard model, since control boxes tend to be common sites of arc flash events.

  • Open Air Arc: The name of this arc type is self-explanatory — an open air arc, or a free arc, is an arc flash that occurs in the open air, exposed on all sides. This is the other most common type of arc flash event, most commonly seen at faulty power lines and cables.

  • Ejected Arc: An ejected arc occurs when the plasma created by an arc flash ejects from the flash site, hitting a nearby worker or piece of equipment. This type of arc can cause serious burns and damage.

  • Tracking Arc: This type of arc is most common at high voltages, or when someone comes in contact with the arc. It involves the arc current conducting on skin or through clothing, causing serious electrical burns.

The first two of these electric arc types are the best understood of the four, and they tend to be the ones taken into consideration in safety standards and calculations for protective equipment. Unfortunately, arcs tend to be much more unpredictable in the real world, and an open air arc can quickly turn into an ejected or tracking arc when the current runs 480V or higher. Because calculations only take open air and confined flashes into consideration, many arc hazard assessments and protective equipment designs are under-rated for the potential risks posed by ejected or tracking arcs.

What Is an Arc Flash’s Range of Intensity?

The intensity of a blast is typically measured in incident energy, expressed in calories per centimeter squared, or cal/cm2. This is the energy measured on a surface at a certain working distance from the origin of an arc flash. This incident energy depends on several variables, including the current of the short circuit and the duration of the arc. Incident energy tends to increase as the fault current and blast duration increases. Incident energy also increases the closer the subject is to the source of the blast.

Second degree burns occur when bare skin is exposed to incident energy around 1.2 cal/cm2

Work zones will usually set an outer boundary for all hazardous equipment, also known as the protection boundary. This boundary is the furthest set boundary from a piece of energized equipment, set at the point at which an employee exposed to an arc flash event would sustain no more than a second degree burn. For reference, second degree burns occur when bare skin is exposed to incident energy around 1.2 cal/cm2.

On the other end of the spectrum is the prohibited boundary. At this distance and closer, the employee might as well be touching the source of the arc flash. While most potential arc flash sources have the potential to produce 2.1 cal/cm2 of incident energy, less than one percent of these potential sources can release as much as 205 cal/ cm2. For reference, third degree burns occur at 8 cal/cm2, and PPE 4 only protects against incident energy of up to 40. These amounts of energy are lethal for any worker within this prohibited boundary, and even some working beyond it.

The potential intensity of an arc flash within a particular work zone is usually determined during a flash assessment using a series of calculations. In turn, personnel use these calculations to set the boundary lines for employees working and observing the hazardous zone.

What Is the Arc Flash Hierarchy of Hazard Control?

To minimize the potential danger or arc flashes in work environments, most companies recognize a system more commonly known as the hierarchy of hazard control. This hierarchy is a system of safety measures charted by the National Institute for Occupational Safety and Health and Centers for Disease Control and Prevention. Also known as the hierarchy of controls for risk management, it lists control measures from most effective to least effective. These controls are:

  1. Elimination: This step involves eliminating the hazard. This is an ideal situation, though it is impractical in the case of arc flashes. Eliminating arc flashes means eliminating electrical systems from the workplace.

  3. Substitution: This option involves substituting the hazard for a safer alternative. For example, in the case of arc flash prevention, this would involve switching out equipment with newer models equipped with more safety measures, reducing the potential for an arc flash event. The only problem with this control method is cost — it’s expensive for companies to switch out their equipment for the newest models.

  5. Engineering Controls: Engineering controls include physically changing the work process to minimize hazards. This tends to be the most favorable of control measures, as it removes hazards at the source without needing to eliminate or replace primary equipment. One example of an engineering control would be an advanced breaker system that monitors and quickly shuts off a circuit as soon as a fault occurs.

  7. Administrative Controls: This measure involves personnel training and regulation. Most commonly, companies use administrative controls like training to improve employee knowledge about hazards and prevention methods. Some companies also limit the amount of time employees can be exposed to a hazard, reducing their chances of being present during an arc flash event. This places the majority of hazard control and safety management on employees, rather than the company itself.

  9. Personal Protective Equipment: This measure involves the use of personal protective equipment, or PPE by employees working around a hazard. This is the last line of defense against a hazard for employees, and the usage of such equipment is the responsibility of the employee, rather than the employer.

Ideally, a company should employ all five controls. By eliminating any unnecessary equipment and replacing older equipment with newer models, employers can reduce the number of hazards their employees face. They can further mitigate any remaining hazards by installing engineering controls and requiring proper training and PPE for all employees working in the environment. In combination, all of these controls can effectively minimize the potential dangers employees encounter during a given workday.

Where Can You Learn More About Arc Flash Events?

These arc flash facts only scratch the surface. From regulations to equipment specifications, the amount of knowledge available on arc flashes and other electrical hazards is massive, and it’s constantly changing as new regulations and discoveries come to light. However, employees working in electrically hazard environments have to know this information — it’s crucial to encourage them to keep up safety procedures and processes as well as help protect themselves and their coworkers from the massive destruction arc flashes can cause. That’s where Technical Skills Development Services can help.

At Technical Skills Developmenbt we specialize inhelping companies of all types meet the latest in OSHA training requirements

At Technical Skills Development, safety training has been our focus for nearly 15 years. We specialize in helping companies of all types meet the latest in OSHA training requirements, and we use OSHA, NFPA 70E and other risk management standards to design our training programs. With our on-site eight-hour training sessions and customized programs, you can rest easy knowing your team of both qualified and unqualified workers is learning everything they need to know about arc flashes and how to prevent them.

Learn how Technical Skills Development can help you meet OSHA standards and contact us today for a free quote.

Qualified vs. Unqualified Electrical Workers

When it comes to workplace safety, federal and state regulations and programs are put in place to protect businesses, workers and the public from a wide variety of hazards. Some professions offer more hazards and dangers than others, but all rely on hiring workers who have the proper training and qualifications imperative to maintaining a safe and productive work environment.

Some of the most important professions that requires strict adherence to a variety of state and federal regulations are skilled electricians and electrical workers. Working with electricity and electrical equipment can be a dangerous hazard for an unqualified worker, and could result in injury or death. Electricity is a powerful force that has the ability to power our homes and equipment, but can lead to fires and injury if not managed correctly.

For many companies, following all of the regulations can be a complicated undertaking, and even confusing at times. There are many essential guidelines to follow, which include proper equipment, clothing, insulation and tools, along with training and assessing potential hazards. One of the best methods to ensure your business and your workers are all on the same page is to create a comprehensive electrical safety program that can address these hazards.

A safety program will not only protect your business from expensive lawsuits and fines, but will also help you ensure the safety of your employees. The first step in achieving an analysis of all potential hazards is to do a self audit, as well as understanding whether or not your workers are properly trained and qualified to meet the requirements. What determines qualifications in electrical workers will be explored more in depth later on. Understanding the regulations first is key to knowing what kind of training and qualifications a worker will need.

What Are the Regulations and Who Enforces Them?

As mentioned above, there are both federal and state regulations, and in some cases local regulations, that need to be followed when operating your business and hiring workers. Qualified and unqualified electrical workers are determined by several different requirements. The regulations are guidelines to help ensure the workers designated for specific tasks have the needed skills and training to perform the job in a safe manner and address all of the potential electrical hazards they may encounter.

For the federal regulations, most companies will need to assess the Code of Federal Regulations under Part 1910 of Title 29. This section of the Code of Federal Regulations addresses all electrical utilities and industrial applications. For those working in construction, Part 1926 of the same title section may also apply.

In addition to the guidelines set in the CFR documentation, companies must also take a look at the National Fire Protection Association, or NFPA, as well as the National Electrical Code, or NEC. Each document outlines several workplace safety standards that are federally enforced. For any other applications, such as electrical utilities, assessing the guidelines covered by the Institute of Electrical and Electronic Engineers as well as the National Electrical Safety Code may be required.

These federal guidelines, while very important, are not the final step in ensuring that all safety regulations and requirements are being followed. State-funded agencies the Occupational Safety and Health Administration, or OSHA, are imperative to maintaining the enforcement of these federal guidelines and application of these safety standards.

Responsibilities of OSHA - enforce workplace standards, identify electrical hazards, assess risk, assess how to select or train workers

If you are unsure if your business meets the requirements and standards set forth by the federal guidelines, consulting with an official from a state inspection office, or OSHA, is an excellent way of identifying any potential problems, which in the long term could be detrimental to the operation of your business. State agencies and OSHA will recommend the best way to address any potential issues and provide you with the documentation needed to get your business, and in some cases your workers, in compliance with all of these regulations.

OSHA’s primary responsibility is to enforce these workplace standards to indentify electrical hazards, assess risks and also, most importantly, how to select or train workers who are qualified to handle the job. OSHA offers a long list of training guidelines to help your workers meet the many requirements. This can include in-class training or on-the-job training to help workers use the proper clothing, equipment and safety procedures and to understand other complex topics such as arc flash protection and assessing hazard risks.

Workplace Regulations and Worker Qualifications

Qualified workers are considered by Article 100 of the National Fire Protection Association 70E as an individual who possess both the skills and knowledge for proper construction and operation of electrical equipment as well as having received the needed safety training to recognize and avoid the potential hazards involved.

In this sense, the guideline is very broad and open-ended, but for good reason. Every specific task will differ from worker to worker and from business to business. However, it is important that the worker is trained on how to perform the job properly and also has the training necessary to recognize and avoid the dangers present.

For electricians, hazards may be different for those tasked with operating electrical equipment. Because of the wide variety of job designations, you can classify your workers into three different categories for determining if your workforce is qualified.

Qualified electrical workers meet all of the training requirements set by the NFPA 70E and OSHA, and can be considered authorized to perform the job correctly. On the other end, you could have a qualified employee who is more specialized, and only qualified to perform a specific task under the training requirements.

Unqualified electrical workers are individuals who have not received the proper safety training or safety guidelines to recognize and avoid hazards. However, they still may have all the skills needed to perform the job correctly, but need proper training to meet the regulatory requirements.

If a circuit or equipment has 50 volts or higher, it needs to be guarded, closed off and protected from everyone who is not a qualified electrical worker

Electrical regulations in the work environment are often specific based on voltages. If a circuit or equipment has 50 volts or higher, it needs to be guarded, closed off and protected from everyone who is not a qualified electrical worker. NFPA 70E demands all unqualified workers are required to be at least four feet from any exposed circuit or equipment ranging from 50 to 750 volts. In some cases, if a qualified electrical worker is present, an unqualified worker may be present under proper supervision.

In addition, electrical testing must always be conducted by qualified professionals and not by unqualified electrical workers who do not have the same level of training. Depending on the duties of the worker, some regulations also demand the individual has a working knowledge of electrical circuits and specific equipment. However, a qualified worker may be considered unqualified for a different task if they don’t have the proper training.

It is important to remember that just because a worker is considered qualified for one task, they may not be qualified for other electrical tasks. In some cases, training may not be enough to meet the standards. Sometimes, local licenses and certificates indicating advanced knowledge of electrical work may be needed to perform certain tasks. In certain jobs, workers’ unions may require specific training in addition to the NFPA and OSHA standards.

Technical Skills Development Services training programs are custom-designed to adhere to OSHA law and NFPA 70E guidelines, while addressing your company’s individual needs. Below we’ll take a brief look at these employee designations to better understand the difference between qualified and unqualified workers.

Qualified Electrical Workers

The most technically skilled and trained employees handling electrical components and equipment are considered your most qualified. They are the workers who have the experience and skills needed to handle highly energized electrical equipment as well as have the required knowledge set by NFPA 70E and OSHA.

Qualified personnel are familiar with all of the proper procedures and precautionary techniques for working with electricity and electrical equipment. They understand the proper protective equipment, arc flash insulation and shielding, and methods that unqualified workers need to learn. These workers are the ones capable of working with electrical conductors and circuits at 50 volts or higher.

To understand whether your workers meet these qualifications, you should ensure they understand the skills and techniques for distinguishing exposed electrical conductors, energized circuits and circuit parts from equipment. They should also be well aware of the hazards present and how to avoid them. Qualified electrical workers are able to use multimeters to troubleshoot electrical problems within a device, understand approved voltage reading devices to check for safe working conditions, as well as a wide range of tasks making them capable of being exposed to energized components and devices.

Qualified Electrical Workers That Are Task-Specific

Some workers may not meet all of the requirements or have all of the technical knowledge needed to be considered qualified for some of the more hazardous tasks. In this case, a worker may still be qualified, but only for task-specific operations.

Some workers may not meet all of the requirements or have all of the technical knowledge needed to be considered qualified for a more hazardous task

Task-specific qualified electrical workers are simply a subgroup of employees who do not have the specific training, procedure knowledge or protection knowledge of their more advanced colleagues. Task-specific workers are not exposed to energized electrical parts, which mitigates their overall risk. They do still have to be aware of many of the hazards, such as arc flashes and arc blasts. For example, a worker who needs to turn on the power for a specific type of equipment still needs training on the proper use and safety measures to operate it safely.

Task-specific workers may need to operate a wide variety of machines, and in some cases, conduct maintenance and repair processes. Qualified workers can perform these tasks by following the training and procedures required for maintaining safe working practices. This includes understanding the proper use of personal protective equipment.

Unqualified Electrical Workers

For everyone else working at your company, they will fall into the unqualified electrical worker category. This can include everyone from office administration to contracted employees. These employees are not technically skilled, trained or equipped to handle any of the tasks associated with electricity or electrical equipment mentioned above. It is imperative that the business follows all safety guidelines to prevent employees from being exposed to energized components or circuits, and that they are not permitted to operate electrical equipment that could result in arc flashes and arc blasts.

How Do I Ensure My Workers Are Qualified?

Determining qualifications is extremely dependent on the regulations and the overall work you need performed at your business. Many companies may wonder how they will meet these complex regulatory standards and ensure their workforce is capable and competent and able to assess risks properly.

For your business, the number one goal is to have the most skilled and well-trained workforce possible to meet these standards. Company managers should review their employee qualifications before and after hiring if the job duties change. By working with OSHA and other agencies, you can better implement an electrical workplace safety program and help your workers find the training needed to do the job.

Documentation of all of these requirements is essential before determining what kind of knowledge and training your workers will need. When conducting your audit and consultation with OSHA, take note of who your most qualified workers are and if you can afford to offer extra on-the-job training or outsourced training options to better your employees.

Each employee should have a clear record of their own qualifications and be able to verify they are capable and competent for performing the needed duties of the job. While some of your employees may have had proper training in the past, it’s also beneficial to consider training refreshers if new equipment or job duties are going to be required of workers who may need an update.

Training Options to Make Sure Workers Are Qualified

Training your employees may seem like a daunting task, but there is a wide variety of options that can help on every level. From in-classroom sessions to on-the-job experience, workers are versatile and are able to learn if shown the right path.

While NFPA 70E and OSHA all offer some level of training documentation, and clearly define their requirements, business demands vary, and these are often too broad and open-ended to be effective for everyone. They are beneficial to understanding the basics, but developing a more comprehensive training program to suit your specific needs is more advantageous in the long run.

Customized training programs will allow workers to identify the hazards associated with tasks they will encounter

With an individualized training program designed specifically to meet your business requirements, you can ensure that your employees are getting the critical knowledge to perform the job efficiently and safely. Customized training programs will allow workers to identify the hazards associated with the tasks they will encounter. It’s important to understand what skills and knowledge your employees will need and help fill in any additional gaps.

Any qualified electrical worker should have at least two to five days of training a year to help maintain their skill level. Even experienced workers who get out of practice may need a refresher to keep their skills up-to-date. Planning a comprehensive training program can greatly reduce or eliminate the costs of lawsuits, regulatory fines and workplace injuries.

Ensuring your qualified and unqualified workers have been trained properly can be the difference between meeting OSHA regulations and breaking the law. Technical Skills Development Services specializes in designing and delivering hazard-specific training that complies with OSHA law. Please contact us today to learn more.

What Are the NFPA 70E HRC Hazard Risk Categories of OSHA?

Electricity is one of the most pervasive and helpful natural forces harnessed for use in our daily lives. However, by its very nature, it poses significant hazards to the human body. If not tended to properly and safely, electricity can cause severe injuries and fatalities. This risk is especially present for the hardworking men and women who maintain electrical infrastructure, machinery, and processes in a variety of today’s modern industries. Electrical engineers, electricians, technicians, operators, and maintenance workers may all be subjected to potential dangers when working in certain environments. It is imperative that they remain qualified and are well educated to help recognize any hazards, and avoid them.

To help business owners recognize these possible hazards and create a safe work environment for their employees, both federal and state regulatory systems have been put in place to help mitigate risk. Founded in 1970, the Occupational Safety and Health Administration, or OSHA, has been critical in the enforcement and education of safe and healthy work practices.

The Occupational Safety and Health Administration, along with several other federal, state, and local regulatory agencies are responsible for setting the common guidelines employers must follow. Failure to meet these regulatory guidelines can result in heavy fines, and it can create a potentially unsafe environment for your employees.

There are several federal codes that are designed to meet safety standards for electrical utilities and other industry applications that demand the use of high voltages. These standards include those found in the Code of Federal Regulations, the National Fire Protection Association, or NFPA, as well as the National Electric Code. OSHA is responsible for inspecting businesses and enforcing these strict standards to help ensure worker safety is universal across the nation.

To make sure the standards are comprehensive and address many of the numerous potential hazards, many of OSHA’s guidelines draw on other codes and regulations set forth by other agencies, including the National Fire Protection Association. NFPA hazard risk categories are often used to assess dangers for electrical workers as well as other employees who may be exposed to the hazards presented.

Electricity can cause electric shocks, burns, fires, and even explosions in some cases, making it both a hazard to human health as well as a fire hazard. In 2007, nearly over 200 employees died as a result of exposure to an electric current. Many others have been severely injured as a result.

In 2007 over 200 employees died from exposure to an electrical current

This includes injuries sustained from electrical fires and explosions. The human body operates on electricity, but it also serves as a conductor, making it potentially lethal if a person comes in contact with an electrical current. Even a current with levels as low as three milliamperes can cause injuries and involuntary muscle reactions from an electric shock.

In some cases, burns may be a result of the improper personal protective equipment or clothing. For fire risks resulting from electricity, the National Fire Protection Association has created a hazard risk category, or HRC, to help employers better recognize potential dangers for their employees. The NFPA’s HRC guidelines also fall in line with the Occupational Safety and Health Administration’s enforcement measures. In this guide, we will take a brief look at the different category levels and what hazards they are designed to protect against.

Having well trained and educated employees who are qualified to recognize and avoid these risks is also imperative to maintaining health and safety at your business. Please take a look at the NFPA 70E Hazard Risk Categories to get a better understanding of what you and your employees should look out for.

What Is National Fire Protection Association 70E?

The National Electric Code and Occupation Safety and Health Administration draw from the National Fire Protection Association for many of their workplace electrical safety standards. The NFPA created 70E, which is the nationally recognized standard for electrical safety used across the United States. It is a document comprising many guidelines and practices and was first adopted in 1976. Since then, the standards have been revised and amended several times to accommodate advances in electrical safety and technology.

NFPA 70E is, and has been, the basis for all enforced electrical worker safety standards on a federal level for many years. Understanding its guidelines is essential to both businesses and employees because it is used across the board for numerous industries, professions, and training programs.

What Are NFPA Hazard Risk Categories

Categories for the NFPA 70E requirements are assigned a designated level ranging from zero to four, which is the highest level risk. Each category for the standards assigns different levels of personal protective equipment for the worker and the proper requirements for working on any type of energized equipment.

Anyone who is going to be working with electricity must be informed, educated, and trained of the NFPA 70 E categories as they are also used by OSHA and the National Electric Code. This includes proper labeling and warnings that need to be placed on panels, controls, and other spaces designed to notify employees that hazards are present. OSHA acts as the enforcement agency and can issue citations and even heavy fines for employers who do not meet the standards. The NFPA 70E was adopted by OSHA, and if you are in compliance, you will meet the acceptable standards required by the administration.

The category levels of hazard risk are based on the calories — or units of heat — per square centimeter in a workspace. A calorie is defined as the amount of energy that’s needed to raise the temperature of a single water gram one degree Celsius at one atmospheric pressure. A second-degree burn can occur from 1.2 calories per square centimeter per second.

Your body uses food, which is broken down to supply your organs with the energy needed to move and function. The number of calories per centimeters squared are used to designate the potential hazard category and the level of personal protective equipment, or PPE, a worker must have available. Improper PPE measures can result in second- and third-degree burns, depending on the hazard risk level. Each category uses a minimum arc rating of personal protective equipment based on calories per centimeters squared.

NFPA 70E Hazard Risk Categories, or HRC, PPE requirements

Here’s a breakdown of the HRC categories and the PPE requirements for each:

HRC Categories - HRC0, HRC1, HRC2, HRC3, HRC4

    • HRC 0 – With a minimum arc rating of personal protective equipment at zero, regular undergarments made from cotton, long-sleeved shirts, pants, hearing protection, safety goggles, and insulated gloves are the needed personal protective equipment required for this category. Only one layer is required to meet the standards.


    • HRC 1 – Again only one layer of protection is needed with an arc rating of PPE ranging to four calories per square centimeter. Cotton undergarments can be worn, but appropriately arc-rated shirts with long sleeves are also needed, as are pants, hard hats, face shielding, hearing protection, leather shoes, insulated gloves with protection, and flame-resistant coveralls.


    • HRC 2 – As arc rating of PPE rises to eight calories per square centimeter, one to two layers of PPE will be needed to meet the standards. At category 2, additional flame-resistant equipment in needed. Cotton undergarments can still be worn, but 12 calorie arc-rated flash hoods, hard hats, and face shields are needed along with coveralls, jackets, and bibs for safe working. In addition, protective gloves with insulation are needed.


    • HRC 3 – At 25 calories per square centimeter for an arc rating, the PPE requirements for previous categories, such as safety goggles, leathers shoes, and insulated gloves are necessary. However, additional PPE components are needed as well, such as short-sleeve natural fiber shirts along with flame-resistant clothing. Three to four layers of PPE is also necessary for HRC 3. It is imperative that workers have 25 calorie arc-rated hoods, coveralls, jackets and bibs, as well as 50″ coats with leggings, which are all required to meet OSHA’s standards.


  • HRC 4 – This is the highest risk category on the list, with calories per square centimeter at 40 for its arc rating of PPE. As with the above mentioned categories, leather shoes, insulated gloves, and safety goggles are all needed. In addition, all arc-rated hoods, coveralls, jackets, and bibs must be 40 cal arc rated. Four layers of PPE is required for working in these high risk levels. An arc flash suit must be rated properly to meet this requirement as it poses the most severe and highest risk to a worker.

What Are Some of the Basic Electrical Hazards?

Now that you have a better understanding of the different hazard risk category levels set forth by NFPA 70E guidelines used by OSHA, you can take a look at some of the common hazards and why they demand certain levels of personal protective equipment.

Arc flashes, or arc blasts, are a form of electrical explosions that can occur. They are often a result of an electrical short. Arc flashes can occur almost anywhere, and they expose workers to high and severe risks during routine practices like maintenance. For example, arc flashes can vaporize metal conductors and explode with plasma bursts and molten metal. Most arc flashes are not this severe, but some explosions can be lethal, causing both fire and injuries to workers and nearby personnel. Arc ratings on PPE are designed based on the probability of both second- and third-degree burns. These pieces of equipment are usually assessed by their total arc thermal performance level, or the amount of heat a flame resistant material can be subjected to until a burn occurs.

Under the NFPA 70E documentation, incident energy is used to describe these types of arc flash hazards. It is the amount, or level, of incident energy determined by calories per centimeter squared. This includes the amount of heat that an electrical arc creates. As mentioned earlier, only 1.2 calories per centimeter squared is enough to induce second-degree burns. Any arc flash levels exceeding 40 calories can be fatal. Fortunately, clothing and equipment capable of withstanding up to 100 calories per centimeter squared is available. However, while it is capable of handling the heat, it is not designed to withstand the force and pressures generated from a blast.

Another hazard to consider is lower fault currents. Fault current levels can determine the arc flash hazard present on a piece of equipment. Engineers can measure fault current levels on distribution systems and devices. Lower fault current levels and longer circuits can increase the severity of incident energy levels.

These are just a few of the hazards to consider when looking at HRC levels. Other standards set by agencies like OSHA and the NFPA require the proper warning labels to be placed on hazard areas and work spaces for employees. It is important that employees are educated about proper procedures, what hazards are present, what type of personal protective equipment is needed, and how to avoid the dangers around them while working.

How to Better Understand NFPA 70E to Meet the OSHA Requirements

When it comes to the many and varied federal, state, and local regulations that need to be met, business owners and managers might feel overwhelmed. There are a wide variety of options available for both you and your employees to better understand how to comply with OSHA’s guidelines. The occupational safety and health administration has numerous online resources available.

The occupational safety and health administration has numerous resources available online

In addition, OSHA often directly supplies employers with training materials, guideline documentation, and reports for particular areas that are not in compliance. However, not meeting OSHA requirements, even if you were unaware, can still result in heavy fines. After a citation is issued, if the problem is ignored, even heavier fines might be levied against your business as it could be seen as willful.

For some employers, setting up an internal training program, ongoing education and inspections might be a better way to maintain worker safety and ensure compliance with OSHA standards. In some cases, employers may not have the resources or man power to invest in maintaining a program of that scale. Supplying employees with protective equipment is not enough to maintain worker safety. Workers must also be knowledgeable, skilled, and aware of the hazards they face on the job.

Employees can benefit from training programs designed specifically to meet the jobs demands, how to identify hazards, and how to avoid them. Customized training programs can help fill in the gaps from the overarching guidelines and requirements supplied to employers by OSHA.

Qualified electrical workers are the only ones permitted to work in high-risk areas under NFPA 70E and OSHA regulations. They must be able to supply documentation indicating they meet the requirements of the job and can handle working in high-risk category situations. At Technical Skills Development Services, we offer employers a way to customize their training and design hazard-specific training designed to meet all of OSHA’s requirements.

Contact us today for more detailed and comprehensive information on our services

Please contact us today for more detailed and comprehensive information on our services. We can ensure your business and workers are trained to meet all of the legal requirements OSHA sets forth.

How to Run an Arc Flash Study and Electrical Hazard Assessment

Arc flashes pose a serious danger to workers in industry. These loud flashes of energy ionize and heat the surrounding air, up to 35,000 degrees Fahrenheit. The CDC reports that five to 10 arc flash explosions occur across the United States every day, and tend to be more common in facilities with denser power structures and higher potential energy.

The resulting heat and pressure wave from an arc flash can injure surrounding employees significantly, causing bruises, burns and even death in some cases.

Generally, an arc flash will occur when a piece of equipment fails due to dust, damage, corrosion or contact with another energized part. Though some of these causes are unavoidable, most of them can be mitigated with examination and implementation of preventative measures. This is why arc flash studies are so crucial to employee safety in arc flash-prone workplaces.

An arc flash will occur when a piece of equipment fails due to dust, damage, corrosion or contact with another energized part

What Is an Arc Flash Study?

An arc flash study, also referred to as an arc flash hazard analysis or an arc flash assessment, is an evaluation of a workplace facility on-site, usually conducted with or by a trained expert in electrical hazard assessment. This study looks at the facility’s electrical system for any potential electrical hazards posing a risk to your employees. These risks include poorly designed electrical pathways and connections, faulty connections and equipment or inappropriate equipment for the application.

A trained expert in arc flash studies and regulations looks for such vulnerabilities, suggests alterations for any fixable problems and then assesses the overall potential for an arc flash to occur.

The study usually takes a day, depending on the size of the facility and the availability of documentation describing the electrical framework of the facility. At the end of the study, the arc flash study expert provides their assessment to the owner, detailing the level of risk and the precautions OSHA requires the owner to take. These precautions include the purchase of protective equipment, employee training and facility equipment upgrades.

Why Does OSHA Require Arc Flash Studies?

The Occupational Safety and Health Act, more commonly called OSHA, came into being on December 29, 1970, as a way to ensure safety and healthy working conditions for men and women across industries throughout the United States.

Part of OSHA — specifically Section 5 — describes the responsibility of employers to remove any recognized hazards likely to cause death or serious physical harm to employees. In June of 1974, these regulations further expanded, requiring the employer to assess the workplace and properly address any potential hazards. Due to their incredible destructive power, OSHA classifies electrical arc flashes as such recognized hazards.

Every year, more than 7,000 burn injuries occur due to arc flashes, 2,000 of which require a hospital stay and 400 of which result in death. Some of those workers hospitalized may miss work for up to a year, and yet others are permanently disabled physically, mentally or psychologically by their injuries and experiences.

Every year more than 7000 injuries occur due to arc flashes

Though arc flashes are common, they are entirely preventable. This places arc flashes under the OSHA umbrella of potential hazards employers must assess and remove when possible.

OSHA and NFPA Requirements for Arc Flash Studies

While OSHA does not detail the requirements for arc flash hazard analyses specifically, the National Fire Protection Association, or NFPA, did so in their 1995 edition of NFPA 70E.

Section 2-3.3.3 details the requirements of flash hazard analyses, and even provides information needed to calculate the flash protection boundary. Specific requirements within NFPA 70E guidelines include the following:

    • Section 110.3 – Standard Electrical Safety: This section requires the employer to implement and document facility-wide electrical safety programs. These programs are protocols designed to direct employee actions to appropriately reflect and account for any electrical hazards present within the facility. Specifically, the section requires the employer to identify and quantify the risks of shock and arc flashes to employees before they begin work, so they can prepare and adjust accordingly.


    • Section 130.5 – Arc Flash Analysis: This section states the importance of an arc flash analysis to determine the arc flash boundary. This assessment is also crucial in determining the incident energy at working distance and the personal protective equipment, or PPE, staff working there should use to protect themselves.


    • Section 130.5 (C) – Labeling: This section requires employers to label all equipment within a work area that will likely be used or maintained while energized. The label details the risk of an arc flash or electrical hazard, the severity of that risk, the arc flash boundary to be observed and the required PPE level of working employees in the area, among other details. Any further content included in the labels may be included at the discretion of the employer.


  • Section 110.1 (A) – Employer Responsibilities: This requirement states that employers hosting contractors or third-party service personnel are responsible for notifying such personnel of any electrical hazards they may encounter while working within the facility. This makes the employer responsible for educating and properly equipping the contractors who work within the facility.

It also means a company using solely contract work must still undergo an arc flash assessment to guarantee the safety of contract employees.

While OSHA requires the mitigation of hazards in the workplace, these NAFP requirements detail the specific responsibilities of employers, the information to be gleaned from an arc flash study and how that information is to be used and acted upon within the workplace.

How Do You Run an Arc Flash Study?

How to Run an Arc Flash Study

In combination, OSHA and NAFP requirements result in a fairly standard arc flash assessment method. Conducted by an expert trained in arc flash analysis studies, OSHA guidelines and NAFP requirements, an arc flash study consists of the following basic steps: 

    1. Collect Documentation: The first step of the process involves gathering all existing drawings of the facility, such as floor plans and riser one-line diagrams. This helps the examiner through the rest of the process. If such documentation does not exist, this means the surveyor must conduct a field survey to create a new one-line. This may lengthen the amount of time needed for the analysis.


    1. Verify Documentation: Before going any further in the arc flash analysis process, the examiner must verify the drawings from the previous step. This verification requires an examination of each site and a comparison with each piece of documentation to determine the accuracy of the information there. If any information is missing or inaccurate, the examiner documents this missing information and develops a more accurate one-line depiction. The examiner will usually combine this step with the first if the examiner needs to conduct a field survey to create a one-line.


    1. Load Information: After completing the field survey and verifying any information collected, the examiner loads the collected information into specialized software, which runs the Short Circuit, Coordination and Arc Flash analyses. 


    1. Run a Short Circuit Study: Once loaded into the software, the analyst reviews the total fault currents and compares them to the duty ratings of the protective devices. If the duty rating of the protective device is greater than the fault current, the device can clear the fault properly. Otherwise, the device will fail and potentially cause an arc flash. Short Circuit studies help determine the energy available for an arc flash.


    1. Run a Coordination Study: After ensuring the viability of each protective device, the analyst examines the coordination of the system as a whole. In proper systems, protective devices will clear any faults without affecting the devices upstream, limiting the effect of the fault on the electrical network. Poorly coordinated systems, on the other hand, result in faults traveling back through the system to trip the building’s main service device, which can bring the whole facility down. Coordination studies also help in evaluating the possibility for an arc flash by helping to determine the amount of time it takes a protection device to clear a fault.


    1. Evaluate Data: These studies and analyses, in addition to an evaluation of the current equipment, provide a more complete idea of the condition of the facility. Based on this preliminary information, analysts can provide recommendations to lower arc flash risks. This data also plays an enormous role in the arc flash evaluation step.


  1. Arc Flash Evaluation: The available arc flash energy, as calculated in the short circuit study, determines the next steps taken by the analyst and facility owner. Using the arc flash energy, the analyst can determine the probable risk to employees, as well as the level of personal protection equipment (PPE) required of workers. This assessment also plays into the labeling and training requirements the employer must meet. In total, this arc flash study provides insights for employers to guarantee the safety of their personnel, helping them implement safe practices and minimize the negative effects in the event an arc flash does occur.

How Can a Company Protect Against Arc Flash?

Steps to Improve Worker Safety

OSHA and NAFP requirements state that employers must take several steps to improve the safety of their employees. This involves both physical protection and general awareness, including the following measures:

    • Worker Training: Over two thirds of all arc flash incidents occur due to employee error, rather than equipment failure or some other cause. Most employees avoid these issues, provided they receive proper training. As part of NAFP 70E regulations, any personnel working within a hazardous work area must be properly trained and informed as to the hazards present within the area. Third-party training specialists versed in OSHA and NAFP regulations tend to be the best providers of such training. In any case, the training must involve basic information, such as the hazards of arc flashes, how to avoid them and the importance of safety precautions like PPE. This simple training session can save lives. 


    • Warning Signs: Both NAFP 70E and the 2002 edition of the National Electrical Code (NEC) require employers to attach labels to any industrial control panels, panel boards and switchboards that may require interaction while energized. These labels detail the potential arc flash hazard involved in using the equipment, in addition to some basic information about the safety level required within the area while energized. This includes the potential energy of an arc flash in the area, the working boundary around equipment and all PPE requirements. More information may be included in this label according to the employers’ preference, but the minimum information required is listed in NAFP 70E.

    • Protective Equipment: OSHA issued regulations regarding safe electrical work practices in 1990, which included a section on the use of personal protection. OSHA 1910.335(a)(1)(i) requires employees working in areas of potential hazard to be equipped with protective equipment appropriate for the parts of the body exposed and the work performed. Specifically, this equipment is referred to as personal protective equipment, or PPE. This PPE is further described in 1910.335(a)(v) as equipment including protective eye or facial wear in environments where there is danger of injury to the eyes or face, and in 1910.335(a)(2)(ii) as protective shields, barriers and insulating materials worn over body parts exposed while working with energized parts. The requirements for this protective clothing were further specified by NFPA 70E in 2000.   Different levels of protection are now required under the regulation, according to the potential risk within each work environment. It also requires the appropriate level of PPE to be detailed in warning labels throughout the facility.

    While these precautions are standard, many employers take further precautions to guarantee the safety of their employees. This includes regular training reviews, stringent protocols and providing more extensive and robust PPE than is required.

    Where Can You Learn More?

    Arc flash assessment is a key part of preventing arc flashes from harming your business and your employees, but these assessments are only half the battle. Employees are the first line of defense against any electrical hazards, so ensuring they know how to prevent hazards is crucial. Not only are training and awareness key parts of any arc flash prevention program, but they’re also required by OSHA and NFPA standards.

    With so much resting on the proper training of your employees, it’s essential to make sure they’re trained by a specialist in the field. If you’re looking to get trained, or to train an employee, on arc flash and electrical hazard safety, Technical Skills Development Services can help.

    Technical Skills Development Services bases our complete training program on the most current OSHA, NFPA 70E and risk management standards, ensuring that your staff receives the most recent information available in the most efficient format. Our teachers come to your facility with a fully realized program, designed to teach your employees how to better handle and analyze electrical equipment and assess it for potential danger.

    Personal protective equipment is a key part of the program, including how to identify and properly use protective equipment. By the end of the program, your employees will know how to effectively prevent an electrical hazard, improving their own safety as well as the safety of their coworkers.

    To learn more about Technical Skills Development Services and how we can help your company with electrical hazard training, contact us today.

OSHA Statistics About Arc Flashes

Arc flashes are some of the most deadly electrical incidents within industry. While arc flashes are entirely preventable when appropriate preventative measures are in place, an average of 30,000 arc flash incidents still occur every year. A 2007 estimate placed the occurrence of these arc flashes at 5 to 10 events per day within the United States alone. Almost all of these events result in injuries to employees, some of which can be deadly.

Wind Turbine Usage Around the World

Across the globe, countries are focusing more than ever on sustainable, domestic energy solutions. For many of them, wind turbines are the solution.

The wind power industry has experienced an unprecedented growth in recent years, with 2015 proving to be the most successful year yet. In 2015 alone, the global wind industry received $109 billion in investments, making it one of the fastest growing industrial markets in the world. This money went toward creating 1,100,000 global jobs, installing 12,107 GW of offshore wind power and producing 3.7 percent of total global electricity.

Wind Turbine Terminology

Modern innovations and improvements in wind turbines have made wind one of the most viable renewable energy options currently in use. According to the American Wind Energy Association, “every state in the United States has either an operational wind energy project, a wind-related manufacturing facility, or both.” There are nearly 49,000 wind turbines spread across 40 states, as well as Guam and Puerto Rico, representing over 74,000 megawatts (MW). As far as the manufacturing of wind turbines, there are over 500 facilities across 43 states.

A Guide to the Most Dangerous Jobs in America

The truth is, some jobs are more dangerous than others. There are certain things that make the lives of every American easier that require highly trained workers to do something especially hard.

Consider these statistics from the Bureau of Labor Statistics: in 2014 there were 4,821 workplace fatalities. Additionally, both the private construction and the mining and oil and gas extraction industries saw sharp increases in fatalities over previous years.

OSHA Compliance Training Guide

According to the Bureau of Labor Statistics, 4,679 workers were killed on the job in America in 2014, which equates to 90 workers being killed every week, and 13 work-related deaths occurring every single day. More than 20 percent of these deaths, or 874 of them, occurred in the construction industry. Approximately 58 percent of these construction-related deaths were caused by one of the following four occurrences:

The Best Safety Glasses and Equipment for Arc Flash Protection and PPE

According to data compiled by the Centers for Disease Control and Prevention, 5 to 10 arc flash explosions occur in electric equipment across the United States each day. Facilities with dense power structures and high levels of potential energy tend to have prime conditions for arc flash events, including substations, data centers, and similar environments. An arc flash releases a significant amount of electrical energy and occurs because of equipment failure contamination, dust, dropped tools and corrosion equipment failure, inadvertent contact with energized parts, dropped tools and several other causes.