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.

NFPA’s 70E Standard for Electrical Safety Is Changing with the Times, and You Should Too

The U.S. Bureau of Labor Statistics reports there were 2,000 fatal and more than 24,000 non-fatal work-related electrical injuries between 2005 and 2015, including those sustained from an arc flash. That’s about one fatality a day out of 11 total work related deaths per day, according to The National Safety Council. Arcing caused by an electrical fault is not to be taken lightly — it can produce temperatures of more than 10,000 F (5,500 C), which is hotter than the surface of the sun. It can cause an explosion with enough force to fling a worker’s body across the room.

Glossary of Arc Flash Terms

Arc flash terminology can be a foreign language. We’ve compiled this glossary of arc flash terms to help you understand the arc flash testing process. We’ve also defined key equations and summarized important regulations.

Arc Flash. Also known as an arc blast, an arc flash is an explosive release of energy caused by a current passing between two points. Arc flashes usually result from dust, damage, improper installation or accidental contact with electrical systems.